Report of the
Herbaceous Ornamental Crop Germplasm Committee
September 1, 1995

1. Introduction

Herbaceous ornamentals are cultivated worldwide and comprise a vast number of genera, species, and hybrids. Most of the floricultural crops grown commercially are herbaceous rather than woody plants, with a few notable exceptions such as azalea (Rhododendron sp.), florists' hydrangea (Hydrangea macrophylla), rose (Rosa sp.), and several foliage plants. Thus, herbaceous ornamentals and floricultural crops can generally be considered synonymous terms.

The genetic resources of herbaceous ornamentals have not received as much attention as most other horticultural and agronomic crops, and this is probably due to three reasons: 1) ornamentals serve an aesthetic function and do not render food, clothing, or shelter; 2) herbaceous ornamentals comprise numerous taxa; and 3) its genetic resources are utilized by several different user groups. However, statistical data indicate that herbaceous ornamentals are a major agricultural commodity in the United States. According to the USDA's Economic Research Service, the greenhouse/nursery (G/N) sector is the sixth largest agricultural commodity group in the United States and accounted for 11 percent of all farm crop cash receipts in 1991 (Johnson, 1992). Grower cash receipts for greenhouse, nursery, and turfgrass products totaled $8.4 billion in 1991, exceeding receipts for all food grain crops by $1.6 billion and were 67 percent higher than the combined values of all sugar and tobacco crops. Floriculture products account for approximately 39 percent of G/N receipts whereas nursery and turf products account for approximately 61 percent of G/N receipts (Johnson, 1992). Thus, the economic value of floricultural crops is comparable to m any "essential " crops. However, the fraction of federally-funded research dollars spent for research on all G/N crops is a mere 0.02 percent (Johnson, 1992). It is also important to note that commercial growers of floricultural crops do not receive direct support from the federal government through production control programs, price supports, or import quotas.

G/N crops play a major role in the economies of several states. G/N crops are produced in all 50 states and rank in the five top commodity groups in 21 states (Johnson, 1992). It is the second largest commodity group in California and Florida. Greenhouse and nursery products are the second largest commodity in the New England region and accounted for 39 percent of total crop sales in 1991 (Staff of the New England Agricultural Statistics Service, 1993). Cash receipts for New England-grown greenhouse and nursery products totaled $391.2 million in 1991. By comparison, cash receipts for New England-grown potatoes and fruit (apples, blueberries, cranberries, etc.) totaled $115.3 million and $210.3 million, respectively, in 1991.

The wholesale value of floricultural crops reached $3.23 billion in 1994, a 5 percent increase above the 1993 level and a 7 percent increase above the 1992 level (Agricultural Statistics Board, 1995). These figures do not represent the total domestic output of floricultural crops, but only the output from growers in 36 surveyed states with gross sales in excess of $10,000 annually. The 1994 wholesale value for the four major floricultural commodity groups was as follows: 1) $559 million for cut flowers and greens (19% of total); 2) $654 million for
potted flowering plants (22% of total); 3) $487 million for foliage plants (16% of total); and 4) $1.28 billion for bedding and garden plants (43% of total) (Agricultural Statistics Board, 1995).

II. Present Germplasm Activities

Herbaceous ornamental genetic resources are utilized by several public and private institutions in the United States. Institutions that are directly involved in utilization of herbaceous ornamental germplasm include: 1) components of the USDA's Agricultural Research Service (ARS), such as the United States National Arboretum and the Florist and Nursery Crops Laboratory; 2) state agricultural experiment stations (AES) and departments within land-grant universities; 3) private-sector companies with breeding and cultivar development programs, or interest in pharmaceutical or industrial uses of plants; 4) public and private botanical gardens; and 5) special-interest plant societies such as the American Begonia Society and the American Plant Life Society.

Many public institutions have active programs in germplasm enhancement and/or cultivar development of herbaceous ornamentals, including the USDA Florist and Nursery Crops Laboratory, University of California, Colorado State University, University of Connecticut, Cornell University, University of Florida, University of Hawaii, University of Illinois, Iowa State University, University of Massachusetts, Michigan State University, University of Minnesota, University of Nebraska, The Ohio State University, The Pennsylvania State University, Purdue University, and University of Wisconsin (Cathey, 1987). Private companies in the United States with herbaceous ornamental breeding programs include Bodger Seeds Ltd. (Lompoc, CA), W. Atlee Burpee & Company (Warminster, PA), B.L. Cobia Inc. (Winter Garden, FL), Denholm Seed Company (Lompoc, CA), Paul Ecke Ranch (Encinitas, CA), Goldsmith Seeds (Gilroy, CA), Holtcamp Greenhouses Inc. (Nashville, TN), Mikkelsens Inc. (Ashtabula, OH), Oglesby Nursery Inc. (Hollywood, FL), PanAmerican Seed Company (W. Chicago, IL), Waller Flowerseed Company (Guadalupe, CA), and Yoder Brothers Inc. (Barberton, OH). Although many public and private institutions are involved in germplasm enhancement and cultivar development, the acquisition of herbaceous ornamental germplasm from centers of diversity or other world locations has been limited. In addition, minimal effort has been devoted to screening accessions for important horticultural traits and accurately describing herbaceous ornamental germplasm in National Plant Germplasm System (NPGS) collections.

III. Status of Crop Vulnerability

Crop vulnerability and genetic erosion of herbaceous ornamentals are major concerns for plant breeders and commercial growers. Whereas a large diversity of floricultural crops are grown commercially, many of these crops have been developed from a very narrow germplasm base. Most of the floricultural crops grown currently were developed during the mid to late 1800s and early 1900s by European breeders using, in many cases, a few specimens obtained from plant collectors, nurseries, or botanical gardens. In the past 40-50 years, ornamental plant breeders have used few wild or unimproved species as a germplasm source but, instead, have relied on genetic variation within segregating cultivars (Ewart, 1981). Domesticated materials (breeding lines, clones, and cultivars) will always remain an important germplasm source, but may not contain the genes necessary for pest resistance or improvement of other traits. Acquisition of new germplasm is critical to plant breeders and will be required for continued crop improvement. It is likely that the genetic diversity found in wild or unimproved germplasm will play an increasingly integral role in floricultural breeding programs, and breeders will turn to accessions or plant introductions for use in crop improvement programs.

As with other plants, floricultural crops are susceptible to attack from many pests, including insects, mites, nematodes, viruses, fungi, and bacteria. Commercial flower growers are constantly searching for environmentally-safe and cost-effective methods of pest control that are not damaging to the finished product or the customer (American Floral Endowment,. 1987). Many of these pest problems may be diminished or eliminated through plant breeding. Breeders are more likely to identify sources of pest resistance in a diverse germplasm collection that includes wild or weedy relatives than among an array of commercial cultivars. Hence, genetic diversity increases the probability that genes conferring resistance can be identified for germplasm enhancement or cultivar development programs.

One of the primary objectives of this Crop Germplasm Committee (CGC) is to assess the quality of the herbaceous ornamental germplasm in the NPGS and make recommendations for broadening and strengthening the germplasm base via additional exploration, acquisition, and evaluation. A recent survey of NPGS holdings of herbaceous ornamental germplasm held at Plant Introduction Stations and Clonal Germplasm Repositories reveals the following: 1) current NPGS holdings of potentially-useful species are, in most cases, represented by a single or a few accessions; 2) nearly all herbaceous ornamental germplasm consists of seed-propagated items and very few accessions are asexual propagules; 3) few accessions represent material collected from centers of diversity and/or origin; 4) many of the major floricultural crops are not represented by a single accession; and 5) some NPGS sites lack qualified personnel to assess germplasm for its potential as herbaceous ornamentals. Outside of the NPGS, there are few collections of herbaceous ornamental crops with 4 broad germplasm base. As a consequence, the vulnerability of many floricultural crops is considerable. There is an immediate need to correct the inadequacies of the herbaceous ornamental collections in the NPGS.

V. Current Status and Needs:

Priority Genera. Since herbaceous ornamentals comprise a vast number of genera and species, the CGC encourages the NPGS to focus on developing comprehensive collections for a few important genera rather than have incomplete collections for many genera. The CGC recommends that the following 24 genera be given the highest priority for collection by the NPGS:

The CGC unanimously recommends that the NPGS initially emphasize herbaceous ornamental germplasm collections that can be maintained as seed, but develop repositories for clonally-propagated herbaceous ornamentals as a long-term goal. In addition, the committee strongly recommends that a list of ARS-approved explorations be forwarded to the Herbaceous Ornamental CGC chair on a timely basis. This would permit the GC to make suggestions to trip participants regarding the collection of endemic herbaceous ornamental germplasm.

Germplasm collection. In most cases, botanical gardens or other existing plant collections are the primary sources of germplasm for new floricultural crops (Christensen and Friis, 1987; Klougart, 1987). However, plant exploration will be required for developing the NPGS collections and also for obtaining germplasm for "new" crops. The joint expedition by Longwood Gardens (Kennett Square, PA) and the USDA to New Guinea in 1970 demonstrates the importance and economic impact of "new" crops germplasm. This expedition resulted in the collection of several Impatiens species (Arisumi and Cathey, 1976), and this germplasm has been transformed into a major floricultural crop: the New Guinea

Impatiens. In the past 20 years, several USDA-sponsored expeditions have concentrated on the collection of woody ornamental germplasm (Cunningham, 1990), but the collection of herbaceous ornamental germplasm by USDA-sponsored expeditions has been very limited. There is a critical need to recollect the species that are the progenitors of the world's major floricultural crops and also to collect new species which may be tomorrow's "new" crops.

Specific recommendations for the collection, evaluation, enhancement, and preservation of germplasm are provided in the synopses for each priority genus (Section VI).

V. Literature Cited:

Agricultural Statistics Board. 1995. Floricultural Crops: 1994 Summary. USDA, National
Agricultural Statistics Service. 117 pp.

American Floral Endowment. 1987. Research Priorities for Floriculture. Report of the
National Research Priorities Summit. 19 pp.

Arisumi, T. and Cathey, H.M. 1976. The New Guinea impatiens. HortScience 11:2.

Cathey, H.M. 1987. Directory 3 of Research Skills for Floriculture. The Ohio State University, Columbus, Ohio.

Christensen, O.V. and Friis, K. 1987. Research and development of unknown new pot plants. Acta Horticulturae 205:33-37.

Cunningham, 1. 1990. Collecting landscape plants in eastern Asia. Diversity 6(3&4):22-23.
Ewart, L. 1981. Utilization of flower germplasm. HortScience 16:135-138.
Johnson, D.C. 1992. Recession impacts and economic outlook for the U.S. nursery, greenhouse, and turfgrass industries. In: Papers presented at the U.S. green industry session, 'Trends, Issues, and Policy Impacts for Greenhouse, Turf, and Nursery Agriculture", December 2, 1992.

Klougart, A. 1987. Exploration, adaptation, evaluation, amelioration. Acta Horticulturae 205:3-11.

Staff of the New England Agricultural Statistics Service. 1993. New England Cash Receipts.
USDA, National Agricultural Statistics Service, Concord, NH.

VI. Synopses for Priority Genera

AGERATUM (Asteraceae)

Introduction:

The genus Ageratum consists of approximately 43 species of annual or perennial herbs and shrubs, all native to Central and South America. One species, A. houstonianum Mill., is an important bedding plant with a domestic wholesale value of approximately $20 million. Capitula have tubular florets that are mostly in shades of blue, but can be pink or white. Inflorescences consist of five to fifteen capitula in (usually) loose clusters. The leaves are opposite, ovate to cordate, and sometimes downy. Plant height varies from 20cm to Im. The short material has a tendency to mutate in stem length with elongated internodes. The species is an annual herb and is indigenous to Mexico. The chromosome number is 2n 20.

Present Germplasm Activities:

Most of the breeding work with A. houstonianum has been performed by private industry. There are some vegetatively-propagated cultivars offered in the trade, but most of the cultivars are propagated from seed. The seed-propagated cultivars in the commercial trade are predominantly F1 hybrids. Hybrid seed is usually produced using self-incompatible clones as seed parents. A disadvantage with this system is that the selected parent lines usually have to be maintained vegetatively.

'Blue Blazer' was the first commercial F1 hybrid to be produced, and was bred by Goldsmith Seeds using two self-incompatible parents. This F1 hybrid exhibited significant improvements over open-pollinated cultivars, including better plant uniformity, vigor, and earlier bloom with dependable seed production. In 1966, Charles Weddle discovered malesterile plants within a population of 'Blue Carpet'. A selection from this material was used as the male sterile parent for the excellent cultivar 'Blue Danube'. 'Blue Mink' is an open-pollinated, tetraploid cultivar of A. houstonianum. 'Blue Horizon' is a new tall, cut flower cultivar which is a triploid F1 hybrid.

Status of Crop Vulnerability:

The status of indigenous populations is unknown because germplasm collecting has not been done recently. The genetic diversity within commercial cultivars of A. houstonianum is expected to be low. Selection of specific characteristics to meet commercial interests intensified the use of self-incompatibility. This has narrowed the germplasm base even further. It is very difficult to obtain highly homozygous inbreds by self-pollination. Most material is self-incompatible after 3 or 4 generations. The resulting selected material, vegetatively propagated, is very prone to loss due to viruses and other diseases.

Germplasm Needs:

A. Collection - Emphasis should be placed on collecting seed from indigenous populations of A. houstonianum and other Ageratum species. The preservation of commercial hybrids should be a low priority. Current NPGS holdings of Ageratum include five seed accessions (one A. conyzoides L. and four of A. houstonianum) that are held at NE-9 (the priority site for Ageratum).

B. Evaluation - Plant introductions should be evaluated for the following characters: plant height, habit, and vigor; foliage size, shape, and color; capitulum diameter; flower color; bloom duration and capacity for reflowering; fertility; and resistance to white fly, aphids, and spider mites

C. Enhancement - Germplasm enhancement activities should be subordinate to collection, evaluation, and preservation of germplasm.

D. Preservation - Ageratum houstonianum is cross-pollinated and has a sporophyticallycontrolled self-incompatibility system. Plant introductions thus require isolation during seed production in order to maintain purity, and several genotypes are needed for intercrossing within PIs.

Recommendations:

Priority of Actions - Germplasm of Ageratum species (including A. conyzoides and A. houstonianum) needs to be collected from several indigenous populations. The collected material needs to be thoroughly evaluated in replicated trials for horticultural traits. Ageratum is cross-pollinated and therefore each accession must be isolated during seed increases in order to maintain genetic purity.

Researchers that may be contacted for additional information:

Yoshiro Arimitsu, Bodger Seeds, Ltd., El Monte, CA
Ageratum Synopsis Prepared by:
Yoshiro Arimitsu, Bodger Seeds, Ltd., El Monte, CA

BEGONIA (Begoniaceae)
Introduction:

Begonia is a large genus that includes at least 1,200 species. The primary center of diversity for the genus is the neotropics (Mexico to Argentina); a second center of diversity is in southcentral Asia (India, Sri Lanka, and China). Some species also are native to the southern, southeastern, and western parts of Africa. Few plant families exhibit the diversity in size, growth habit, and foliage morphology that is found within the genus Begonia. Among Begonia species, height ranges from 5 cm to 2 m. Leaves range in size from under 2 cm to over 50 cm. The leaf surfaces vary from glabrous to densely hairy. The inflorescences are usually axillary and dichasial. Flowers are characteristically monoecious, and the pistillate flowers have inferior ovaries. Flowers are predominantly white, but may be pink, red, orange, or rarely yellow. The fruit is either papery, leathery, or fleshy. The basic chromosome numbers (x) for the genus are 6, 7, and 13. Chromosome numbers range from 2n = 28 to 66.

The fibrous-rooted begonia (B. x semperflorens-cultorum Hort.) and the tuberous-rooted begonia (B. x tuberhybrida Voss.) are the most important types that are grown as bedding plants. Fibrous-rooted begonias are apparently derived from B. cucullata var. hookeri and B. schmidtiana. Cultivars developed from crossing these two species were released in 1878. In the middle 1800's, six tuberous-rooted Begonia species were discovered in the Andes of South America (Bolivia, Peru): B. boliviensis, B. clarkei, B. davisii, B. pearcei, B. rosiflora, and B. veitchii. All except B. rosiflora are progenitors of modem cultivars of tuberous-rooted begonia. In 1993, begonias ranked number four in the total percentage (7.5%) of crop mix in respect to seed-propagated plants used for bedding plant production. This translates into a gross wholesale value of approximately $49 million.

The most important types grown as potted flowering plants are the Hiemalis begonias (B. x hiemalis Fotsch) and the Cheimantha begonia (B. x cheimantha Everett ex C. Weber). Hiemalis begonias were developed from crosses between B. socotrana Hook. and B. x tuberhybrida. Cheimantha begonias were developed by crossing B. dregei Otto & A. Dietr. with B. socotrana.

Present Germplasm Activities:

Most Begonia breeding is done in private industry. Some breeding work is also being done at botanic gardens and by amateur hobbyists, e.g., members of the American Begonia Society.

Status of Crop Vulnerability:
The status of indigenous populations is unknown at present. No scientific germplasm collection trips have been taken recently, although hobbyists probably still continue to collect material from the wild. The genetic diversity of present-day Begonia cultivars is unknown.

Commercial Begonia cultivars are susceptible to several diseases. Hiemalis and Cheimantha begonias exhibit varied levels of susceptibility to powdery mildew (Erysiphe cichoracearum). Hiemalis begonias are very susceptible to bacterial leaf spot (Xanthomonas begonias).

Most Begonia species do not lend themselves to bedding plant production due to undesirable habit, a long cropping period, or poor seed set. Most of these species, therefore, are relegated to hobbyist or botanical collections and are propagated vegetatively.

Germplasm Needs:

A. Collection - Currently, GRIN lists 14 accessions at S-9 and 2 accessions at NCRPIS for Begonia. Emphasis should be placed on collecting Begonia germplasm from indigenous populations. Acquisition of older line-bred items for the NPGS should be a second priority. Acquisition of F1 hybrid cultivars should have the lowest priority. Since many botanical gardens have Begonia collections, it would be worthwhile to obtain their inventory lists and determine if any accessions should be acquired by the NPGS.

B. Evaluation - Each accession should be evaluated for the following traits: growth habit and vigor; foliage size, shape, and color; time from seed sowing to flowering; flower size and color; fertility; and resistance to Erysiphe cichoracearum and Xanthomonas begonias.

C. Enhancement - Germplasm enhancement activities should be subordinate to collection, evaluation, and preservation of germplasm.

D. Preservation - Emphasis should be placed on preserving seed of indigenous species and any line-bred cultivars that can be obtained.

Recommendations:

Priority of Actions - NPGS accessions of wild species and line-bred cultivars of Begonia should be greatly increased. Inventories of Begonia species from botanical gardens should be obtained to determine if any accessions should be acquired by the NPGS. All germplasm should be thoroughly evaluated for the traits described above.

Begonia Synopsis Prepared by:

Lowell C. Ewart, Michigan State University, East Lansing, MI

CATHARANTHUS (Apocynaceae)

Introduction:

The genus Catharanthus is comprised of approximately seven species of mostly perennial herbs. The single species in section Androyella (C. pusillus) is native to India. All other species, contained in section Eulochnera, are native to Madagascar. The various species, their morphological descriptions, distributions, and putative crossing abilities are described by Veyret (1974). The chromosome number for all Catharanthus species is 2n = 16.

Ornamental cultivars of Catharanthus are all derived from species in the section Eulochnera. Germplasm of C. roseus and C. trichophyllus has provided the primary material for development of ornamental cultivars. As an ornamental, Catharanthus, more commonly known as Madagascar Periwinkle or Vinca (not to be confused with the genus Vinca), is valued for its drought and heat tolerance. Currently, the wholesale market value of Catharanthus cultivars exceeds $40 million annually. Though Catharanthus cultivars currently only account for about four percent of the total bedding plant market, their popularity will likely increase due to their heat and drought tolerance.

In addition to its value as an herbaceous ornamental, alkaloid extracts of Catharanthus roseus have been used in folk medicine as a diuretic, and antidysenteric, an anti haemorrhagic and for wound healing. Folk medicine also used extracts for treatment of diabetes. During the 1960's, as a result of the discovery of the valuable cytotoxic alkaloids in Catharanthus roseus (especially vinblastine and vincristine), this species became one of the major fields of interest in modern plant cell biotechnology. During the last 30 years, C. roseus has been used in modern medical practice as the most important plant in treating cancer. Vinblastine sulphate is used particularly to treat Hodgkin's disease but is also used against lymphosarcoma, choriocarcinoma, neuroblastoma carcinoma of the breast, lungs and other organs, and in acute and chronic leukaemia. Vincristine sulphate is used particularly to treat acute leukaemia in children and lymphocytic leukaemia, but is also used against Hodgkins disease, Wilm's tumor, neuroblastoma, rhabdosarcoma and reticulum sarcoma. Since these drugs were first marketed, childhood leukaemia survival rates have increased from IO % to 95 %. The value of alkaloids derived exclusively from C. roseus exceeds $100 million annually.

Present Germplasm Activities:

Ornamental breeding and germplasm enhancement on Catharanthus have been conducted by Dr. Ron Parker at the University of Connecticut. Most of the current breeding activities are done by private companies including Goldsmith Seeds Inc. (Gilroy, CA), PanAmerican Seed Co. (Elbum, IL), and Waller Flowerseed Co. (Guadalupe, CA), although other flower seed companies may also have current breeding programs. At present, there is no priority site within the NPGS for Catharanthus. No extensive germplasm repositories are known to exist elsewhere in the world although pharmaceutical companies may possess limited collections.

GRIN lists 27 accessions of Catharanthus roseus. None of these accessions are from the native range of the species. Twenty-two of the accessions are PVP protected ornamental cultivars, whereas the remaining five accessions are naturalized weedy ornamentals from Mexico and Guatemala. No accessions of the other Catharanthus species are held within the NPGS.

Genetic Vulnerability:

As indicated, the native range of Catharanthus section Eulochnera is entirely limited to Madagascar. Despite the once-rich biotic diversity of this island, the region now stands as one of the most outstanding examples of environmental devastation in the world. Widespread destruction of habitat and overpopulation have undoubtedly disrupted and eliminated native Catharanthus populations. The Missouri Botanical Garden and the Madagascar government have undertaken efforts to preserve examples of the remaining biota. Unfortunately, most of the protected sites lie outside the ranges of Catharanthus species. Catharanthus ovalis, in some reports, has been listed as extinct. The security of other species and populations is unknown. Genetic variability in Catharanthus roseus, an especially critical species, is unknown. Because of the very limited distribution of native populations and sensitivity of these populations to human encroachment, the best and perhaps only way to minimize genetic vulnerability is to collect and preserve representative wild germplasm.

Except for private germplasm collections held by seed or pharmaceutical companies, no other germplasm repositories are known to exist. Genetic diversity in commercial cultivars is limited primarily to backgrounds of Catharanthus roseus and C. trichophyllus. Predominance of only a few cultivar series suggests that genetic diversity in commercial cultivars is low.

A major shortcoming of commercial cultivars is their susceptibility to various pathogens, especially Phytophthora. In addition, commercial cultivars exhibit a limited flower color range. Current cultivars are adapted to warm climatic conditions, but perform poorly in cool or wet climates.

Germplasm Needs:

A. Collection - Representative collections of all of the wild species should be obtained as soon as possible. Delay will only result in further deterioration of native populations and potential loss of genetic diversity. Seeds and/or cuttings can be made in the field. Considering the limited range of many of the species, attempt should be made to collect from ecologically diverse regions within the range of the species.

B. Evaluation - Emphasis should be placed on collection of variability within each species. Collections should be evaluated for horticulturally valuable traits including novel forms, colors, habits, and disease resistance. As much as possible, collections should be evaluated for potential use in pharmaceutical applications.

C. Enhancement - Given the vulnerability of all species to extinction, the first priority should be directed towards mere collection of natural genetic diversity. Beyond preservation of genetic diversity, no enhancement or modification of the germplasm is necessary or desired. Early enhancement of the germplasm may only serve to limit its utility in as yet unknown roles.

D. Preservation - Currently, there is no priority site within the NPGS for Catharanthus germplasm. Therefore, a priority site needs to be established for Catharanthus. Germplasm may be easily stored as seed for long periods of time.

Recommendations:

Germplasm of all available species should be acquired from native populations as soon as possible. Once acquired, the wild germplasm can be distributed for plant improvement programs. Collections should be maintained in such a way that horticultural traits do not have priority over potential other pharmaceutical uses.

Researchers that may be contacted for additional information:

R.N. Bowman, Goldsmith Seeds Inc., Gilroy, CA
D.G. Holden, Waller Flowerseed Co., Guadelupe, CA

Catharanthus Synopsis Prepared By:

R.N. Bowman, Goldsmith Seeds Inc., Gilroy, CA

DENDRANTHEMA (Anthemideae; Compositae)
Introduction:
The genus Dendranthema is comprised of approximately 40 species of mostly herbaceous (sometimes woody) perennials with corymbose inflorescences. The capitula usually contain both disc and ray florets, but some species lack ray florets. The center of diversity for the genus is eastern Asia, although some taxa are found as far west as Europe. The most common chromosome numbers for the genus are 2n = 18, 36, and 54, with x = 9. However, chromosome numbers of 2n = 42, 45, 52, 60, 70, 72, and 90 have also been reported.

By far, the most common Dendranthema taxon in cultivation is the florist's mum [D. x grandiflorum (Ramat.) Kitam.; formerly C. x morifolium Ramat.]. Cultivation of this hybrid-species dates back over 2,000 years. It is used as a cutflower, potted plant, and garden subject. A 1993 survey of 36 states indicated that D. x grandiflorum was cultivated on approximately 2011 acres and had a wholesale value in excess of $176 million. Pot mums are second only to poinsettias, whether viewed in terms of monetary value or in units sold.

Breeding over the past 2,000 years has created and changed the wild hybrid-species D. x grandiflorum from what it was, i.e., a two- to five-foot-tall erect or spreading plant with small, daisy-like flowers, into the spectacular florist's mums we have today. The National Chrysanthemum Society recognizes thirteen classes of flower types, ranging from anemones and singles (daisy type) to full doubles (decorative type), and with flower petals ranging from reflexed to fully incurved. Ray petals may be flat, tubular, or combinations thereof (spoon, spider, quilted), and in almost all colors except blue. Flower size can vary from less than one inch to over ten inches in diameter. The chromosome number of D. x grandiflorum is 2n = 54.

Other Dendranthema species that are often cultivated are:

Dendranthema pacifica (Nakai) Kitam. [ = Ajania Pacifica (Nakai) Bremer & Humphries] - a low spreading perennial from the eastern coast of Japan. The abaxial surface of the thick leaves is tomentose and silvery-white. Leaf margins often curl, giving the appearance of a green leaf with a white or silver border. The one-quarter inch capitula are devoid of ray petals, and appear as clusters of little yellow buttons. Plants are often utilized as a perennial ground cover. The species exhibits resistance to leaf miners, and has been crossed with D. x grandiflorum in an effort to incorporate this trait into the florist's mum. The reported chromosome number is 2n = 90.

Dendranthema indicum (L.) Des Moul. - one of the putative parents of D. x
grandiflorum. A perennial from Japan and China with small, yellow, daisy-like capitula in a loose corymb, growing from two to three feet tall. This species has been utilized to develop a series of garden chrysanthemums. The reported chromosome numbers are 2n = 36 and 54.

Dendranthema weyrichii (Maxim.) Tzvelev. - a low-growing, stoloniferous perennial from Japan with white to pink flowers. The plant grows to perhaps one foot tall. The chromosome number is 2n = 54.

Dendranthema zawadskii (Herbich) Tzvelev. - a two- to three-foot-tall plant with white or pink daisy-like flowers. This species has been crossed with D. x grandiflorum to create the Korean chrysanthemums which have been used as garden mums. The reported chromosome numbers are 2n = 54 for D. zawadskii var. zawadskii, and 2n = 18 for D. zawadskii var. latilobum.

Present Germplasm Activities:

Other than some breeding research being done at the University of Minnesota, most of the Dendranthema breeding is being done in private industry. Very little research on Dendranthema in the United States utilizes interspecific hybrids. However, interspecific hybrids are used in mum breeding programs in China and Japan, where new habits and forms of mums have been created, in some cases with resistance to adverse environmental conditions (drought, pollution, low temperatures) or pests (insects, diseases). As always, plant breeders are trying to develop new and novel types of plants, preferably within species that the public has been growing for some time. We have very little idea as to what can be obtained through interspecific hybridization within Dendranthema, i.e., what new colors, habits, resistances, etc., can be obtained by crossing D. x grandiflorum with other Dendranthema species, and what new markets we can enter with these new interspecific hybrids.

Status of Crop Vulnerability:

The current status of indigenous populations of Dendranthema species is unknown. Commercial lines and cultivars are the primary source of germplasm for current Dendranthema breeding programs. Fortunately, Dendranthema is primarily clonally-propagated crop and the available germplasm is (usually) highly heterozygous. However, the germplasm base is very limited, considering the large size of the industry.

Dendranthema x grandiflorum cultivars are host to a number of insects and diseases, and, as a consequence, receive frequent applications of pesticides during crop production. For worker health, environmental, and economic reasons, it is desirable to develop cultivars that require fewer pesticide applications. Therefore, identification of clones that exhibit resistance to diseases and/or insects is needed for future breeding efforts. It is likely that wild species will be the sources of pest resistance for Dendranthema breeding programs.

Germplasm Needs:
A. Collection - The NPGS currently has few Dendranthema accessions. Current NPGS holdings include twelve clones among six taxa (D. arcticum, D. x grandiflorum, D. indicum, D. japonicum, D. pacificum, D. zawadskii, D. zawadskii var. latilobum), and some seed of D. x grandiflorum. Most of the clones are at NC-7, but the clones of D. zawadskii are at the National Arboretum. Seed of D. x grandiflorum is held at NSSL. The current NPGS holdings of Dendranthema represent less than 15 percent of the available species. The NPGS's Dendranthema holdings should be increased to include seed of at least 20 representative accessions per species, preferably obtained from several different locations within the species' range. Each accession should consist of open-pollinated seed collected from numerous plants at each location.

B. Evaluation - Where and when possible, multiple plants from each accession should be evaluated for disease and insect resistance, and other attributes including (but not limited to) growth habit and rate; size, color, and type of capitula; and keeping quality.

C. Enhancement - Collection, evaluation, and preservation of germplasm should receive the highest priority.

D. Preservation - see Recommendations section.

Recommendations:

Habitat destruction is occurring on every continent, often at an alarming rate, with the simultaneous destruction of many potentially valuable species. Therefore, it is imperative that seed of all Dendranthema species is collected in the near future, preferably from several wild populations. Maintaining the plant materials as seed will simplify germplasm maintenance and minimize the space required for the collection. The accessions should be grown out and increased periodically so that viable seed will be available for distribution to interested parties.

Researchers that may be contacted for additional information:

L.J. Glicenstein, Yoder Brothers, Inc., Salinas, CA
Dendranthema Synopsis Prepared by:
L.J. Glicenstein, Yoder Brothers, Inc., Salinas, CA

DIANTHUS (Caryophyllaceae)
Introduction:

The genus Dianthus consists of approximately 300 species of annual, biennial, or perennial herbs that are native from Europe to western Asia and extending south to southern Africa. Many of the species hybridize with each other, and therefore the exact number of species is unknown. The second edition of the International Dianthus Register contains about 27,000 entires or names of Dianthus releases/cultivars. The chromosome numbers for Dianthus species are n = 15, 30, and 45.

Dianthus species and hybrids are grown commercially for use as outdoor bedding plants or for cut flowers. Plants grown for bedding outdoors include Border Carnations, Sweet William, and Pinks. Plants grown for cut flowers include the Glasshouse (or Florist's). Carnation and sweet william.

The Glasshouse (or Florist's) Carnation is derived mainly from D. caryophyllus L., but also includes D. arboreus L., D. chinensis L., and D. knappii (Pant.) Asch. & Kanitz ex Borb. in its parentage. Dianthus caryophyllus is native to the Mediterranean region.

The Border Carnation (D. caryophyllus L.) is grown as an annual or perennial, depending on the location and source of plant material. Border Carnations are similar to the Florist's Carnation but the former usually have smaller flowers and are shorter in height. The chromosome number is n = 15.

Sweet William (D. barbatus L.) is grown as a commercial cut flower and as a bedding plant. The species is usually biennial, and is native to mountain pastures of central and southern Europe. Plant have dark green foliage and cymose inflorescences with densely clustered florets in shades of red, pink, salmon, or white.

The Pinks comprise several species and interspecific hybrids of Dianthus, and include Allwood's Pink (D. caryophyllus x D. plumarius), Alpine Pink (D. alpinus), Cheddar Pink (D. gratianopolitanus Vill.), China Pink (D. chinensis L.), Cottage Pink (D.plumarius L.), Deptford Pink (D. armeria L.), and Maiden Pink (D. deltoides L.).

In the United States, the economic value of Dianthus is chiefly due to production of the Florist's Carnation. The wholesale value of florist's carnations produced in the United States was $64.5 million in 1985.

Present Germplasm Activities:
The number of public institutions in the United States that are conducting research on Dianthus has declined within the past decade. Breeding research at Colorado AES (Fort Collins) is terminating due to retirement of the principal investigators. Limited work on cultivar development is being conducted at the Nebraska AES (North Platte) and at several private companies. AES researchers in Indiana (Purdue University) and California (University of California, Davis) are studying genetic variation for postharvest quality in the Florist's Carnation. The NPGS priority site for Dianthus is the North Central Regional Plant Introduction Station (NCRPIS) at Ames, IA. Holdings at NCRPIS include =65 Dianthus accessions representing 32 species, and an additional 7 accessions are maintained at the National Seed Storage Laboratory (NSSL).

Status of Crop Vulnerability:

In most of the Mediterranean area, native populations of Dianthus are threatened by overgrazing. A few plants can still be found on rocky outcroppings that cannot be reached by goats. The status of indigenous populations in the former Soviet Union is unknown. In the United States, Dianthus germplasm is maintained by private companies, individual collectors, botanical gardens, universities, and NCRPIS. For the most part, breeders must rely on germplasm obtained from commercial companies or botanical gardens.

Most of the new cultivars are developed from existing commercial cultivars. The level of genetic diversity in commercial cultivars is unknown, but is probably significantly lower than the original parental material collected from the wild.

Several traits in Dianthus could be improved by breeding, including pest resistance, calyx strength, stalk strength, winter hardiness, and the period of flowering. The main disease pathogens of Dianthus are Alternaria dianthi, Botrytis cinerea, Fusarium oxysporum f.sp. dianthi, Phialophora cinerescens, Pseudomonas caryophylli, Uromyces dianthi, and several viruses. The major invertebrate pests of Dianthus are aphids, thrips, and spider mites. Hardiness and disease resistance are the major goals for breeding Dianthus for use as garden perennials. A short juvenility period and plant vigor are important selection criteria in breeding Dianthus for use as annual bedding plants.

Germplasm Needs:

A. Collection - Emphasis should be placed on the following germplasm: 1) collecting material from indigenous populations; and 2) procuring material that is maintained in European and Asian collections. Currently, NCRPIS has 65 Dianthus accessions, and the collection is being expanded through contacts with Indices Seminum. Sixteen of these accessions originated from the former Soviet Union, and the other three were obtained in Iran, Japan, and a domestic source (Colorado). The NCRPIS collection at should be expanded to include accessions of D. caryophyllus from southern and western Europe. Germplasm of other Dianthus species should also be obtained, especially species that will hybridize with D. caryophyllus. Collecting germplasm that may be resistant to disease pathogens should be a priority.

B. Evaluation - Plant introductions should be systematically evaluated for the following
traits: 1) compatibility of crossing with the larger-flowered D. caryophyllus types; 2) disease resistance or tolerance; 3) duration of flowering; 4) winter hardiness; 5) fragrance; 6) flower size and color; and 7) plant habit. Initially, Dianthus germplasm should be maintained and evaluated in a mild winter region until winter hardiness has been determined.

C. Enhancement - Dianthus improvement programs are mainly conducted by private companies. Enhancement programs are needed to increase the duration of flowering, calyx and stalk strength, disease resistance, and winter hardiness.

D. Preservation - A broad genetic base will be needed for future breeding programs. Therefore, NCRPIS should acquire and maintain a diverse collection of Dianthus germplasm for utilization by public and private breeding programs. Some Dianthus germplasm will need to be maintained as asexually-propagated clones, thus adding to the cost and complexity of preservation. Seeds of Dianthus species and hybrids should remain viable for 15 to 20 years when stored under cool, dry conditions.

Recommendations:

The NPGS Dianthus collection should be expanded to include germplasm from indigenous populations and from European, Asian, and domestic collections. Botanical gardens in China, France, Italy, Japan, Korea, Malaysia, Portugal, Spain, and the United Kingdom should be excellent sources of Dianthus germplasm. All accessions should be systematically screened for the horticultural traits described above. Dianthus accessions and evaluation information should be valuable to breeders in the public and private sectors.

Researchers that may be contacted for additional information:

J. Elsley, Wayside Gardens, Hodges, SC
D.T. Lindgren, The University of Nebraska - Lincoln, North Platte, NE
M.P. Widrlechner, USDA/ARS, NCRPIS, Ames, IA

Dianthus Synopsis Prepared by:

D.T. Lindgren, The Univeristy of Nebraska - Lincoln, North Platte, NE

DIEFFENBACHIA (Araceae)

Introduction:

The genus Dieffenbachia consists of about 30 species of erect herbs native to tropical America. Commercially-grown Dieffenbachia rank among the top ten ornamental tropical foliage plants in terms of wholesale dollar value. They are prized for their attractive variegated foliage and tolerance of interior environments.

Present Germplasm Activities:

Germplasm enhancement and breeding research on Dieffenbachia is being conducted by the Florida AES at Apopka, Florida. Program goals include breeding for improved plant form, novel types of foliar variegation and increased branching. The NPGS priority site for Dieffenbachia is the National Clonal Germplasm Repository at Miami, FL (CR-MIA). There are approximately four Dieffenbachia accessions maintained at CR-MIA.
Status of Crop Vulnerability:
The genetic diversity within existing Dieffenbachia cultivars is difficult to assess, because the botanical nomenclature of this genus is unclear and due to the existence of many intra- and interspecific hybrids made in the late 1900's. Most commercial cultivars are assigned to the species maculata or seguine, although this may be erroneous. However, it is likely that most of the available genetic diversity can be attributed to those two species accounting for only a small portion of what exists in wild populations.

The most popular Dieffenbachia cultivars are propagated asexually either via tissue culture or by tip cuttings. There are no seed propagated varieties. Tissue culture has made production of disease- and virus-free cuttings possible which has lessen the severity of these problems in production. Mutations arising from tissue-culture produced populations have led to selections with improved plant form and branching characteristics but this has not significantly increased genetic diversity.

The major Dieffenbachia pest is spider mites. Collection of germplasm with resistance to spider mites would be of major importance to development of improved cultivars.

Germplasm Needs:

A. Collection - Emphasis should be placed on material collected from indigenous populations throughout tropical America.

B. Evaluation - Plant introductions should be evaluated for resistance to spider mites, growth habit, leaf shape and size, and degree of branching.

C. Enhancement - There is a breeding program at the Florida AES but additional research is needed to screen Dieffenbachia accessions for mite resistance.

D. Preservation - The majority of Dieffenbachia germplasm is held by botanic gardens or private collectors. Maintaining germplasm is difficult because plants must be asexually propagated, they may be large in size and must be kept. in heated and shaded greenhouses or other enclosed structure.

Recommendations:

Priority of Actions - Germplasm of Dieffenbachia species should be collected from indigenous populations in order to expand current collections. Once collected, material should be distributed to breeders for screening, evaluation, and utilization in plant improvement programs.

Researchers that may be contacted for additional information:

R. J. Henny, University of Florida, Apopka, FL
Dieffenbachia Synopsis Prepared by:
R .J. Henny, University of Florida, Apopka, FL

EUSTOMA (Gentianaceae)
Introduction:

The genus Eustoma is comprised of two species. Eustoma grandiflorum (Raf.) Shinn., commonly known as Prairie Gentian or Lisianthus, is native from the midwestern prairies of the United States south to Mexico. Eustoma exaltatum (L.) Griseb. is native to the southern United States, Mexico, Central America, and the West Indies.. The two species may represent different ecotypes of the same species, for both species are interfertile and produce fertile progeny. In cultivation, E. grandiflorum grows like a biennial, and first produces a rosette which bolts into a single flowering stem after cold treatment, then dies after flowering. In contrast, E. exaltatum grows more like a perennial in cultivation and produces additional shoots each season. Both species have purple flowers that are funnel-shaped to , campanulate, but corolla lobes of E. exaltatum range up to 2.5 cm in length whereas those of E. grandiflorum are 5 to 6 cm in length. Most of the plant material in cultivation is E. grandiflorum (2n = 2x = 36). This species is an important seed-propagated cut flower crop in Europe and Japan. In the United States, E. grandiflorum is just beginning to be grown, but has the potential to become an important bedding plant, flowering potted plant, and cutflower.

Present Germplasm Activities:

Most commercial cultivars have been developed by Japanese seed companies. Several Japanese companies have been breeding Eustoma for over 90 years, and have released superior cultivars in a range of flower colors (pink, white and purple) and flower forms (sprays, doubles, picotees, and bicolors). Breeding within the United States has only recently begun. Several different dwarf cultivars suitable as either bedding or potted plants have been released by the breeding programs in the United States and Japan.

Sakata Seed Co., Takii Ltd., Daichi Co., Geo. Ball Co., and Dr. Brent Harbaugh of the University of Florida have extensive collections of Eustoma species and cultivars.

Status of Crop Vulnerability :

In North America, populations of E. grandiflorum are not common and can be locally threatened because of habitat destruction. Eustoma grandiflorum has been collected in Colorado, Florida, Texas and Arizona. In Mexico, populations of E. exaltatum are more common than are E. grandiflorum populations within the United States. Eustoma exaltatum has been collected from Florida, California and Baja Mexico.

Most commercial cultivars have been derived from limited E. grandiflorum germplasm that was collected in the early 1900's and improved in Japan. However, significant genetic variation for flower color and flower shape exists within the cultivated species. In addition, preliminary data suggest there is genetic diversity for several isozyme alleles in cultivated germplasm of E. grandiflorum.

Germplasm Needs:

A. Collection - Emphasis should be placed on collecting seed from indigenous populations of E. exaltatum and E. grandiflorum. Several horticulturally important characteristics can be obtained from native germplasm. For example, E. exaltatum collected from its southern range or low-elevation sites can be used to incorporate heat tolerance in commercial E. grandiflorum germplasm. Many of the superior E. grandiflorum cultivars either rosette or produce few flowers at high temperatures. Expanded use of Eustoma as a bedding plant requires that heat tolerant cultivars be developed. In addition, incorporation of basal-branching and dwarf or semi-dwarf habit would enhance the uses and acceptance of this crop. Eustoma grandiflorum germplasm from the northern limit of its range may be useful in developing perennial cultivars.

Recommendations:

Priority of Actions - Emphasis should be placed on collecting seed of E. exaltatum from
Mexico, Central America, and the West Indies, and collecting seed of E. grandiflorum from
Nebraska, Kansas, and Colorado.

Researchers that may be contacted for additional information:
R. J. Griesbach, USDA, ARS, Florist and Nursery Crops Laboratory, Beltsville, MD
Eustoma Synopsis Prepared by:
R. J. Griesbach, USDA, ARS, Florist and Nursery Crops Laboratory, Beltsville, MD

HEMEROCALLIS (Liliaceae)

Introduction:

Hemerocallis, commonly known as daylily, is a popular herbaceous perennial. Numerous complex hybrids are commercially available, and these hybrids are noted for their drought and heat tolerance, winter hardiness, plant vigor and resistance to most disease and insect pests.

Extensive hybridization has occurred during the past 100 years. Approximately seven species were used in developing the current cultivars: H. flava (L.) L. (= H. lilioasphodelus L.), H. thunbergii Hort. ex Bak., H. middendorfii Trautv. & C.A. Mey, H. minor Mill., H. dumortieri E. Morr., H. aurantiaca Bak., and H. fulva (L.) L.

Species are rarely used today in breeding. Hemerocallis species have a very restricted flower color range, and are either yellow or various shades of orange. Cultivars have been selected that express novel colors, e.g. red, purple and pink. Species germplasm offers little for extending the range of flower color.

Small-flowered cultivars have been obtained through breeding. These cultivars usually produce small (5 cm) flowers on rather tall (40 cm) inflorescences. Hemerocallis minor produces small yellow flowers and on small-leaved plants, and this species was very important in creating these dwarf daylilies. However, the inflorescences of H. minor are quite tall. Hemerocallis nana W.W.Sm. & Forr. is a truly dwarf species that produce small flowers on inflorescences that are less than 25 cm tall. This species, however, is not in cultivation today.

Two traits have been used to prolong the flowering season. One trait that extends the season increases the number of flowers per determinate inflorescence. In certain cultivars, indeterminate infloresences can also be produced. A second trait that extends the season increases the number of inflorescences. In most cultivars and species, the infloresences develop during fall and start to elongate during spring. In the "reblooming" cultivars, inflorescences develop and elongate immediately as the new shoots mature. Hemerocallis multiflora Stout could be used to extend the flowering season: this species is known to produce up to 100 flowers per determinate inflorescence, while most Hemerocallis species rarely produce over 20 flowers.

Present Germplasm Activities:

Almost all of the Hemerocallis breeding done today is by amateurs. Current breeding efforts are focused on extending the flowering season, reducing plant size, and developing new flower shapes and colors. Breeding efforts are divided between the diploid and the tetraploid cultivars that can not be intercrossed to produce triploids.

The NPGS priority site for Hemerocallis is the United States National Arboretum (USNA) in Washington, D.C, and includes the following species: H. altissima, H. aurantiaca, H. citrina, H. coreana, H. dumortieri, H. esculenta, H. exalta, H. forrestii, H. fulva and its many forms, H. hakurensis, H. lilioasphodelus, H. littorea, H. middendorffii, H. minor, H. multiflora, and 41 accessions unidentified as to species.

Status of Crop Vulnerability:

The status of indigenous populations of Hemerocallis species is unknown. At present, commercial cultivars are the primary source of germplasm for plant improvement programs. The level of genetic diversity in commercial cultivars is unknown.

The genetic resources of Hemerocallis have not been fully exploited. Only half of the known species have been used in breeding of commercial cultivars.

Germplasm Needs:

A. Collection - Several species are available in private and public collections. The Hemerocallis collection at the USNA (Washington, D.C) contains identified and new, unidentified species. However, the following species from mainland China are not currently held in any collection: H. aurantiaca, H. forrestii, and H. nana. These species contain genes for dwarfness and anthocyanin coloration, and are needed for plant improvement programs.

B. Evaluation - All Hemerocallis accessions should be evaluated for important horticultural traits including plant height, number of flowers per inflorescence, length of the flowering period, cold hardiness, salt tolerance, and disease resistance.

C. Enhancement - Useful traits in Hemerocallis species should be introgressed into cultivated germplasm.

D. Preservation - Most species are held in collections that have sufficient funds or interest for plant maintenance.

Recommendations:
Introgression of useful traits from Hemerocallis species into cultivated germplasm should receive the highest priority. Amateur breeders are less likely to accomplish this task, and therefore an ARS/AES geneticist should be responsible for introgression. Secondly, several important Hemerocallis species (including H. aurantiaca, H. forrestii, and H. nana) should be collected from indigineous populations, maintained in the NPGS collection, propagated, and made available for distribution.

Researchers that may be contacted for additional information:

J. Elsley, Wayside Gardens, Hodges, SC

HIPPEASTRUM (Amaryllidaceae)
Introduction:

The genus Hippeastrum Herbert (amaryllis) consists of approximately 60 entirely New World species (one species has naturalized in Africa). The species are concentrated in two main areas: 1) eastern Brazil; and 2) the central southern Andes of Peru, Bolivia and Argentina, on the eastern slopes and adjacent foothills. Little of this genetic diversity is represented in modern amaryllis hybrids. Hybrid strains were produced primarily from the following relatively small number of species:

H. vittatum Herbert (Brazil, Bolivia, Peru; 2n = 22, 44): 2- to 6-flowered, variable in form, perianth white with longitudinal red to mauve stripes on the tepals.

H. leopoldii Dombrain (Bolivia, Peru, chromosome number unknown): 2 flowered, very wide-spreading and regular perianth, the tepals proximally bright red with a bifid white keel in the lower half, apically white.

H. pardinum (Hook. f.) Lemaire (Bolivia, 2n = 22): 2-flowered, tepals with greenish background, suffused and densely spotted with red.

H. reginae Herbert (Mexico to Bolivia, 2n = 33, 44): 2- to 4-flowered, perianth red with whitish green keels and throat.

H. puniceum (Lamarck) Kuntze (Mexico through South America including the West Indies, 2n = 22, 33): 2-4 flowered, perianth salmon, orange, white, pink or red and yellowish-green in the throat.

H. aulicum Herbert (Brazil to Paraguay, 2n = 22): frequently epiphytic, flowers 2, perianth bright crimson, green at the base.

Present Germplasm Activities:

A breeding program emphasizing Brazilian diploid amaryllis species not currently represented in modern cultivars has been underway at the University of Florida's Fort Lauderdale Research and Education Center since 1988. Objectives are to develop evergreen cultivars with attractive foliage and fragrant flowers of novel floral form and coloration patterns with resistance to hippeastrum mosaic virus and red scorch (Stagonsopora curtisii). A breeding program focusing primarily on Andean species is conducted in Escondido, California under the aegis of Fred Meyer, a commercial floriculturist and plant breeder. Collection, evaluation and preservation of Hippeastrum germplasm are conducted as part of both programs. Two breeding programs focusing on hybrid material exclusively are located in Bradenton, Florida (University of Florida Gulf Coast REC) and Gainesville (Amaryllis Bulb Company, a commercial firm). A breeding program of unknown scope is also underway at Oklahoma State University. Many amateur breeders around the country are also involved in hybridizing amaryllis. The NPGS priority site for Hippeastrum is CR-MIA (Miami, FL). There are approximately 11 Hippeastrum accessions maintained at CR-MIA.

Status of Crop Vulnerability:

Commercial breeding efforts subsequent to the initial flurry of primary hybridization in amaryllis has largely been concentrated among the hybrids themselves. Thus, there has never been any attempt by breeders to accumulate and maintain a broadly-based germplasm collection of wild species. The overwhelming majority of Hippeastrum species are diploid, with somatic chromosome number of 2n = 22. Virtually all of the complex hybrid material presently in cultivation is tetraploid, a result of both selection for tetraploid progeny (often associated with plant and flower size increases in hybrid amaryllis) and incorporation of a few natural tetraploid species in early hybridization efforts. It is thus evident that little more than 10% of the genomic diversity of Hippeastrum is represented within commercial cultivars. Even among breeders using wild-collected species in their breeding programs, most of the germplasm can be traced to a single (often undocumented) collection which has then been propagated vegetatively or by seed. The most obvious means to reduce or minimize the genetic vulnerability of commercial amaryllis is the expansion of the gene pool currently represented in cultivars.

Although many new species of Hippeastrum have been described in the last 30 years, it is evident from recent systematic approaches to the genus that many of these new taxa represent only variants of more widely-ranging species. It is thus difficult to compose a highly accurate estimate of the vulnerability of wild populations. Habitat destruction is without a doubt the most serious threat to wild amaryllis populations, especially species that occur within or at the margins of tropical forest ecosystems (probably about 50% of currently known species). The coastal rain forest of Brazil, for example, has been reduced to 2% of its original extent, and forest-dwelling amaryllis species such H. reticulatum Herbert have no doubt suffered losses. Nonetheless, it is still possible to find populations of this species in residual forest communities in eastern Brazil. Of the six important amaryllis species listed above, H. pardinum, and, until recently, H. leopoldii, were known only from their original collections. H. brasilianum (Traub & Doran) Ravenna, an important component of the Fort Lauderdale breeding program, is currently known only from cultivation in Brazil.

Hippeastrum mosaic virus is probably the greatest limitation on expansion of amaryllis production in the United States. There has never been any attempt to assess degree of resistance among amaryllis species. Hippeastrum papilio (Ravenna) Ravenna does not manifest mosaic symptoms, and thus has been an important component species for the Fort Lauderdale breeding program. Hybrids of this species show considerable variation in their expression of visual mosaic symptoms. Thus breeding for resistance to this virus and, secondarily, to the fungus Stagonospora curtisii are useful directions for any breeding program with amaryllis. On other fronts, the species H. blossfeldiae occurs along the coast in Brazil where it receives direct salt spray, suggesting that it might impart salt tolerance to its hybrids.

Germplasm Needs:
A. Collection - While it would be beneficial to place emphasis on new collections of amaryllis species from indigenous populations, the social and political problems occurring in a number of nations where amaryllis species are most widely represented present great obstacles to success. Such collections need to proceed with sensitivity to the sovereignty of those countries, and preferably in cooperation with scientists within those countries. It is imperative that each wild population be sampled adequately, because most diploid Hippeastrum species exhibit self-incompatibility. Peruvian and Bolivian amaryllis should be a particular focus for collection because they appear to be the least well known. There should also be a sustained attempt to access domestic holdings of amaryllis species collections through a central data base.

B. Evaluation - Amaryllis introductions should be assayed for resistance to hippeastrum mosaic virus and Stagnospora red scorch. Ploidy level of new collections should be determined. New introductions should also be evaluated for flower number, foliage quality (including persistence), and for any attributes of floral morphology that could be considered novel and exploitable for breeding efforts.

C. Enhancement - Breeding programs are underway at the University of Florida, Oklahoma State University, and by both amateur and commercial interests. Enhancement need not be a priority at the NPGS site(s) unless it coincides with breeding programs in progress at the same location(s).

D. Preservation - A sizable species collection (=20 spp.) is maintained at the University of Florida-IFAS Fort Lauderdale REC. A large collection (= 30-40 spp.) is also under the private ownership of Fred Meyer in Escondido, California. A number of amateur breeders around the country maintain small species collections; the best collections of these type are located in California. Additional germplasm collections are present in Argentina, Brazil, Chile and Peru, though the exact status of their condition is not well known.

Recommendations:

A program should be initiated to access collections currently in the United States, whether in the possession of botanical gardens, university departments, commercial firms or private collectors. It should be requested that seed or offset bulbs of these collections be deposited at the NPGS priority site (CR-MIA). Virused accessions will need to be micropropagated using documented protocols for virus elimination. Secondly, NPGS should support a program of collection of new Hippeastrum germplasm from Latin America. Research on long-term storage of amaryllis seed needs to be undertaken as well, since most amaryllis bulb collections eventually contract mosaic virus in cultivation.

Researchers that may be contacted for additional information:
A.W. Meerow, University of Florida, Fort Lauderdale, FL
Hippeastrum Synopsis Prepared by:
A.W. Meerow, University of Florida, Fort Lauderdale, FL

IMPATIENS (Balsaminaceae)

Introduction:

Impatiens is an exceedingly large and complex genus, and is comprised of 600 to 1000 species of annual or perennial herbs or subshrubs. They are mainly distributed in the tropics and subtropics of Asia and Africa, with a few species native to the temperate regions of China, Europe, and North America. Three separate centers of diversity have been proposed: 1) the Himalayas, which gave rise to the temperate species (x = 7, 9, 10); 2) southern India and Sri Lanka, which gave rise to the African species (mostly x = 8); and 3) southeast Asia, and extending to Indonesia and New Guinea (mostly x = 7).

Impatiens wallerana Hook. f. (formerly I. sultanii sultana Hook. f.) is native from Tanzania to Mozambique and is found in damp, often shaded locations from sea level to 1800m (n = 16). It is the most widely cultivated species in the genus and is believed to be the second most economically-important flowering plant in the United States. The farm gate value for impatiens sold in the United states is roughly estimated at $200 to $250 million in 1992. Most cultivars of I. wallerana are seed-propagated.

Also horticulturally important are the New Guinea impatiens, hybrids involving I. aurantiaca Teysm., I. hawkeri Bull., and possibly other species (2n = 4x = 28). Plants are used as flowering pot plants indoors or for bedding outdoors. Most cultivars are propagated by shoot-tip cuttings. The wholesale value of New Guinea impatiens is approximately $12 million annually.

Of lesser importance are I. balsamina L. (balsam impatiens), an artificial hexaploid hybrid of I. platypetala Lindl. x I. hawkeri (sold commercially as 'Tango' and 'Tangeglow'), I. niamniamensis Gilg., I. repens Moon, and I. sodeni Engl. & Warb.

Present Germplasm Activities:

A small species collection is maintained at the Connecticut AES (Storrs), and interspecific hybridization research was carried on there at least until the mid- 1980s. It is not known whether this program is still active. A fairly extensive collection is maintained at Kew Gardens (Richmond, United Kingdom).

In the United States, breeding programs for I. wallerana are conducted by PanAmerican Seed Company (Elbum, IL), Goldsmith Seeds, Inc. (Gilroy, CA), and Bodger Seed Company (Lompoc, CA). Several foreign seed companies also have breeding programs on I. wallerana. Breeding of New Guinea impatiens is being carried out by Ball Floraplant (G.J. Ball Company, Nipomo, CA), PanAmerican Seed Company (Elbum, IL), Mikkelsen's, Inc. (Ashtabula, OH), and Iowa State University (Ames, IA).

The NPGS priority site for Impatiens is CR-MIA (Miami, FL). At present, there are 5 Impatiens accessions at NCRPIS, 1 at NPMC, 23 at Glenn Dale, and 5 at NSSL.

Status of Crop Vulnerability:

Although we have no specific knowledge concerning the status of wild Impatiens populations, we can assume that ecological destruction in tropical Africa, the Himalayas, Sri Lanka, and southeast Asia is diminishing the habitat for many species. Many of the tropical species are highly endemic, and these species should receive high priority for collection due to their genetic vulnerability. The few temperate species are far more widespread and should not require collection at this time.

Wild populations of I. wallerana are very heterogeneous, and natural hybrids between I. wallerana and I. usambarensis are observed in the wild. Impatiens cinnabarine may also be genetically compatible with I. wallerana. The size of the original I. wallerana collection is not known, and it is also not known if other accessions were added to the original collection since breeding work began in the 1940s. A wild I. wallerana seedling collected in the early 1950s from a naturalized population in Costa Rica conferred genes for dwarf growth habit, flower color, and pigment patterning (including the "eyed" and "blush" types). Intercrossing and selection have generated a vast amount of genetic variation for plant height, flower color, flower size, time of flowering, and several other traits.

Impatiens species may be able to contribute useful traits to I. wallerana. Impatiens usambarensis is reported to grow in more exposed, sunny habitats than I. wallerana, and therefore might be expected to confer genes for sun tolerance. Flower color in I. wallerana is controlled by several modifying and intensifying alleles, and the flower color range may be extended in this species by hybridization with I. usambarensis. Yellow flower color does not exist in I. wallerana, but several other Impatiens species have yellow flowers, including I. auricoma Baill. Primary hybrids between I. wallerana and I. auricoma have been obtained.

Germplasm Needs:

A. Collection - Germplasm needs to be collected from wild populations for several Impatiens species. Impatiens wallerana, I. usambarensis, and their natural hybrids need to be collected from Tanzania, Mozambique, Malawi, and other African countries. Additional germplasm of I. auricoma and similar species may include individuals that are more genetically cross compatible with I. wallerana, increasing the probability of introgressing yellow flower color into the commercial cultivars. Alternatively, a diverse collection of species germplasm may provide material for the domestication of new Impatiens crops with unique characteristics. Possibilities include different flower forms (ex. - I. nzoana from Ivory Coast or I. tincoria from Kenya), an extended color range (ex. - flower color in an unidentified Impatiens species from Madagascar ranges from yellow to rose and purple), novel plant habits (ex. - the rhizomatous species I. Serpens from Tanzania has a prostrate growth habit), and frost hardiness (ex. - the tuberous species I. cinnibatina from Tanzania). Most of the desirable traits are found in the African Impatiens species. Detailed information is found in the book, 'Impatiens of Africa,' by Christopher Grey-Wilson, A.A., Balkema, Rotterdam (1980).

Several of the Himalayan Impatiens species exhibit interesting traits and should be collected. The Nepalese species I. decipiens, for example, has metallic blue flowers. Some of the Himalayan species have been collected by the G.J. Ball Company in conjunction with the Royal Botanic Gardens at Kew and Edinburgh. This collection is still under study, but the species generally have proven less amenable to cultivation that the African species. Typically, the seeds require stratification for germination and the plants are slow growing, non-vigorous, and sparse in flowering.

The 1970 expedition by the USDA and Longwood Gardens (Kennett Square, PA) to New Guinea resulted in the collection of several Impatiens species. Over the past two decades, this germplasm has been transformed into a major floricultural crop: the New Guinea impatiens. Detailed records of this expedition should be studied to determine the breadth and depth of this original effort and whether a follow-up expedition is required for germplasm collection.

B. Evaluation and Enhancement - Because of the commercial importance of this genus, private companies will be willing to cooperate with USDA/AES scientists in the evaluation and enhancement of Impatiens germplasm. Chromosome counts for accessions, studies of interspecific hybridization, and colchicine treatment of primary hybrids are activities that could be performed by USDA/AES scientists.

C. Preservation - Most Impatiens species are protandrous and highly outcrossed, and therefore plant introductions require isolation during seed production in order to maintain purity. Generally, Impatiens seeds are short-lived. Seeds begin to lose vigor within two years even under ideal storage conditions, and seldom retain viability longer than four years. Ideally, germplasm should be maintained vegetatively in a clean, well-managed greenhouse or in vitro. At this time, virtually all existing Impatiens germplasm in the United States is maintained by private companies.

Recommendations:

The first priority is collection of Impatiens species from central tropical Africa and Madagascar. The second priority should be the procurement of germplasm from Kew Gardens. The Kew gardens germplasm should serve to complement and broaden (but not duplicate) the African collection. The involvement of the acknowledged Impatiens expert, Christopher Grey-Wilson (currently editor of the Alpine Garden Society Magazine), should be sought for collecting germplasm in Africa.

An adequate site needs to be designated within the NPGS for the Impatiens collection. The collection should not be located in a hot, dry climate. Due to the susceptibility of Impatiens to several viruses (TSWV, TMV, TRSV, CMV, etc.), the collection should be maintained in a facility that minimizes the possibility of virus infection by excluding virus vectors. Tissue culture facilities may be valuable for plant maintenance and embryo rescue.

Finally, a cytogeneticist will be required to perform chromosome counts and crossability studies on the collected germplasm.

Researchers that may be contacted for additional information:

E. Leue, PanAmerican Seed Co., Elbum, IL
Impatiens Synopsis Prepared by:
E. Leue, PanAmerican Seed Co., Elbum, IL

LIATRIS (Asteraceae)

Introduction:

The genus Liatris consists of approximately 32 species of perennial herbs with erect, leafy, usually slender stems that terminate in a spicate or racemose inflorescence. The genus is indigenous to North America, with species occurring in almost every state of the Union east of the Rocky Mountains, and extending into southern Canada and northern Mexico. The center of genetic diversity for Liatris is the United States.

Liatris is comprised of a taxonomically complex group of species. Most of the diagnostic characters of the species are to be found in the capitula, including the characteristics of the phyllaries, number of florets per capitulum, presence or absence of pubescence inside the corolla tube, and degree of plumosity of the pappus hairs. The perennating structure is usually a globose or ovoid corm, although some species produce a rhizome or elongated root crown.,

At least 13 species, together with several interspecific hybrids and botanical varieties, have been introduced into cultivation and are grown commercially as garden plants and/or cut flowers. The three most common species in cultivation are L. aspera Michx., L. pycnostachya Michx., and L. spicata (L.) Willd.

Liatris aspera is a perennial herb with erect, stiff stems, 40-110 cm in height, and linear to linear-lanceolate leaves. The sessile capitula contain 25-40 florets with purple corollas. It is native from southwestern Ontario to Minnesota and south to Florida and Texas, and inhabits dry, sandy soils of dunes, fields, abandoned roads, and railroad embankments. The natural flowering period for L. aspera is August.

Liatris pycnostachya is a coarse perennial herb with erect, stiff stems, 60-150 cm in height, and linear leaves. The sessile capitula contain 5-12 florets with purple, rose-purple, or white corollas. The species is not readily distinguished from L. spicata, except by its recurving, acuminate rather than appressed, obtuse phyllaries. It is native from Indiana to South Dakota and south to Florida, Louisiana, and Texas, and typically inhabits damp meadows and tall grass prairie. The natural flowering period is during August and September.

Liatris spicata is the most commonly cultivated species, and has recently become an important commercial cut flower. Stems are erect and stiff, 60-150 cm in height, with linear leaves. The inflorescence is a dense cymose spike composed of sessile or peduncled capitula with 4-18 florets. The corolla is purple, rose-purple, or white. It is distributed from Long Island to Michigan, south to Florida and Louisiana, and is endemic to marshy places and damp meadows. The natural flowering period is July through September.

Liatris spicata is a common garden perennial and is gaining steadily in importance as a commercial cut flower. In commercial practice, Liatris is propagated by seed or corm division. Commercial growers of L. spicata prefer 1-year-old corms for cut flower production. Most L. spicata cultivars are raised from seed by specialist corm producers, who then sell the 1-year-old corms for flowering in the following year. Plants sold under the name 'Callilepsis' (also listed as L. callilepis or L. callilepsis) are L. spicata selections that are propagated exclusively by corm division. Crops of 'Callilepsis' are generally more uniform than crops from seed-propagated corms. In addition, the greatest market demand for cut Liatris is for stem lengths greater than 80 cm; 'Callilepsis' is the best cultivar for producing long stems. However, the rate of increase from corm division is slow; as a consequence, 'Callilepsis' corms cost about 2/2 times more than seed-propagated corms.

Production difficulties include poor and/or slow seed germination, nonuniformity of stem length and flowering time among seed-propagated cultivars, disease susceptibility, and sporadic flowering during the first season from a mid-winter sowing. Improvements in seed germination, disease resistance, and crop uniformity are thus needed.

Limited information has been published on breeding and genetics of Liatris. The haploid chromosome number for the genus is 10, and the following species are diploids (2n = 20): L. acidota, L. aspera, L. cylindracea, L. graminifolia, L. Helleri, L. punctata, L. pycnostachya, L. scariosa, L. spicata, and L. squarrosa. For L. punctata, 2n .= 40 has also been reported.

Present Germplasm Activities:

Breeding research on Liatris is currently being conducted by the Massachusetts AES at Amherst, MA and the Wisconsin AES at Madison, WI. The goals of the Massachusets AES program include improved seed germination and early flowering. The goals of the Wisconsin AES include short-stature cultivars for potted plant production and improved disease resistance. The NPGS priority sites for Liatris are Western Regional Plant Introduction Station (WRPIS) at Pullman, WA and CR-MIA (Miami, FL). Activities at WRPIS include collection and preservation of germplasm as seed samples. A few plant accessions are maintained at CR-MIA.

Status of Crop Vulnerability:

Three Liatris species are listed (or are candidates for listing) on the Federal Endangered Species List: L. helleri, L. ohlingerae, and L. provincialism The status of indigenous populations of other Liatris species is unknown. At the present time, commercial cultivars are the primary source of germplasm for plant improvement programs. The level of genetic diversity in commercial cultivars is unknown. The genetic resources of this genus has yet to be fully exploited.

In the United States, L. spicata is subject to several diseases, including leaf spots (Phyllosticta liatridis and Septoria liatridis), rusts (Coleosporium laciniariae and Puccinia liatridis), stem rot (Sclerotinia sclerotiorum), powdery mildew (Erysiphe cichoracearum), and wilt (Verticillium albo-atrum). Commercial cultivars of L. spicata are either highly susceptible or exhibit limited resistance to these pathogens. Incorporation of genes conferring resistance into commercial cultivars would be valuable to the industry.

Germplasm Needs:

A. Collection - Emphasis should be placed on material collected from indigenous populations. Currently, WRPIS has 5 seed accessions of L. punctata and the CR-MIA (Miami, FL) has 2 live plant accessions ( 1 L. tenuifolia and 1 unknown Liatris species). The Soil Conservation Service (NPMC) has seed accessions of L. pycnostachya and L. scariosa. The NPGS holdings should be expanded significantly to include approximately 20 accessions of each Liatris species that is not on Federal Endangered Species List, and approximately 50 accessions for the economically important species, i.e., L. aspera, L. pycnostachya, and L. spicata.

Sources of resistance to the pathogens described previously are needed in L. spicata. Novel growth habits, flower forms, and flower colors are needed in L. spicata.

B. Evaluation - Plant introductions should be systematically screened for disease resistance and evaluated for the following characters: % seed germination, plant height, stem stiffness, florets per capitulum, and corolla color.

C. Enhancement - At present, there are breeding programs at the Massachusetts AES, the Wisconsin AES, and private seed companies. However, more research is needed to screen accessions for sources of disease resistance. Germplasm enhancement activities at the NPGS priority sites for Liatris (WRPIS and CR-MIA) should be subordinate to collection, evaluation, and preservation of germplasm.

D. Preservation - The majority of the Liatris germplasm used in domestic improvement programs is maintained by private seed companies. Within the NPGS, emphasis should be placed on developing and maintaining populations that are representative of the germplasm of an area rather on single plant collections. Liatris is an entomophilous genus that is pollinated by Lepidoptera and Hymenoptera. Experiments involving the bagging of individual capitula and entire inflorescences have revealed the presence of self-incompatibility (SI) in L. aspera, L. pycnostachya, and L. spicata; SI has also been documented in L. scariosa. Plant introductions thus require isolation during seed production in order to maintain purity, and several SI genotypes are needed for intercrossing within Pls.

Recommendations:

Priority of Actions - Germplasm of the important Liatris species (L. aspera, L. pycnostachya, and L. spicata) needs to be collected from indigenous populations in order to preserve the wild material for plant improvement programs. Secondly, the NPGS holdings should be expanded to include accessions of each Liatris species that is not under cultivation. The collected material needs to be thoroughly evaluated in replicated trials for horticultural traits.

Researchers that may be contacted for additional information:

T.H. Boyle, University of Massachusetts, Amherst, MA
D.P. Stimart, University of Wisconsin, Madison, WI

Liatris Synopsis Prepared by:
T.H. Boyle, University of Massachusetts, Amherst, MA

LILIUM (Liliaceae)

Introduction:

The genus Lilium consists of about 70 species which are found in the temperate and subtropical zones of the northern hemisphere. The species occur in a broad band across North America and from Spain eastward to Kamchatka and the Philippines. The genus is divided into the following seven sections: 1) Martagon; 2) American; 3) Candidum; 4) Oriental; 5) Asiatic; 6) Trumpet; and 7) Dauricum. Some of the sections are partitioned into subdivisions.

Plants are long-lived perennials with scaly bulbs, stolons or rhizomes. Stems are upright and unbranched, with alternate or whorled leaves. The funnelform, cup-shaped or campanulate flowers are solitary and terminal in racemes, panicles or umbels. Flower color ranges from white to yellow, orange, red, purple or maroon.

Lilium species are endemic to a wide range of edaphic conditions which include bogs, calcareous soils, and dry, hard, stony soils. They grow in full sun to heavy shade. Some Lilium species are distributed widely, e.g., L. martagon spans Europe and L. philadelphicum covers the North American continent. Others are confined to small isolated areas, e.g., L. macklinae which grows on one mountain in Burma and L. pitkinense which is found in one bog in California.

Propagation of many species is often slow to difficult. Thus, ornamental characteristics of many species have not been introgressed into commercial cultivars. Habitat destruction and a long regeneration period threaten many species.

The ornamental value of lilies as potted plants, cut flowers, and garden plants is recognized worldwide. The food and medicinal value of some species is documented, but poorly studied. Wholesale value of lilies remains undetermined, but is estimated at about $61 million annually. Lilies of the greatest ornamental value are derived from species in the Asiatic, Oriental, and Trumpet sections. Species of the remaining four sections have ornamental value, but have been inadequately studied due to rarity, specific growth requirements, and/or propagation difficulties.

Present Germplasm Activities:

In the United States, breeding and germplasm enhancement of lilies is being conducted by members of the lily societies and by private companies in the Pacific Northwest and southeastern Minnesota. The NPGS priority site for Lilium is NCRPIS (Ames, IA). The NCRPIS Lilium collection consists of 11 accessions, including L. carniolicum, L. cordatum, L. distichum, L. leucanthum, L. martagon, L. philippinense, and L. tenuifolium. Two additional Lilium accessions are held at USNA.

Status of Crop Vulnerability:

The status of indigenous Lilium populations is unknown. However, many of the American species (approximately 20) are located in small isolated areas. These areas are threatened and many are being destroyed. At the present time, commercial cultivars are the primary source of germplasm for plant improvement programs. Gametophytic and unilateral incompatibilities can restrict genetic recombination. Most cultivars are diploid (n = 12), although a few tetraploids (n = 24) have been developed. Several disease-causing organisms and invertebrate pests have been reported to attack Lilium species and cultivars. Disease-causing organisms include Botrytis, Cercospora, Cercosporella, Cladosporium, Colletotrichum, Corynebacterium, Cylindrocarpon, Fusariwn, Erwinia, Heterosporium, Macrophomina, Penicillium, Phytophthora, Pseudomonas, Puccinia, Pythium, Ramularia, Rhizoctonia, Rhizopus, Sclerotium, and Uromyces. Many viruses and virus complexes incite severe epiphytotics. Invertebrate pests include insects, nematodes, mites (Rhizoglyphus), and slugs (Lamix). Insects of concern include Acyathosiphon, Aphis, Apocelus, Bradysia, Chysomphalus, Ctenothrips, Cumeues, Diabrothica, Emboloecia, Franklinella, Hercenothtips, Lilioceris, Lithrops, Macrosiphum, Myzus, Neolasioptera, Neomyzus, Papaimema, and Scutigerella. Nematodes of concern include Aphelenchoides, Meloidogyne, and Pratylenchus. Identification of sources of resistance or tolerance to pests or disease-causing organisms is needed.

Germplasm Needs:

A. Collection - Emphasis must be placed on collecting material from indigenous populations. Currently, the NPGS Lilium collection at NCRPIS has 11 accessions. The NPGS holdings should be expanded significantly to include the five species of the Martagon section, the 21 species of the American section, the eight species of the Candidum section, the six species of the Trumpet section, and the single species of the Dauricum section. The NPGS collection should also maintain a collection of older cultivars that are in danger of being permanently lost.

B. Evaluation - Plant introductions should be screened systematically for resistance or tolerance to pests or disease-causing organisms. Accessions should be evaluated for: plant height and habit; leaf form; and flower form, orientation, and color. Systematic evaluation of species and cultivars is needed since previous evaluations (executed by members of lily societies) have not been thorough.

C. Preservation - In the United States, the majority of Lilium germplasm used for breeding is maintained by amateur breeders. A comprehensive collection consisting of multiple accessions per species needs to be developed within the NPGS.

Recommendations:

Priority of actions - Due to deterioration of specialized habitats, collection of as many species as possible must be done to preserve the remaining wild material. Emphasis should be placed on collecting Lilium species which are progenitors of the commercial cultivars, i.e., those within the Asiatic, Oriental, and Trumpet sections. Collected germplasm needs to be evaluated in replicated trials for ornamental, medicinal, and culinary value. Accessions with horticultural merit need to be propagated and made available for plant improvement programs.

Researchers that may be contacted for additional information:
J. Elsley, Wayside Gardens, Hodges, SC
D.P. Stimart, University of Wisconsin, Madison, WI
M.P. Widrlechner, NCRPIS, Ames, IA

Lilium Synopsis Prepared by:
D.P. Stimart, University of Wisconsin, Madison, WI

LOBELIA (Lobeliaceae)

Introduction:

Lobelia is a large genus consisting of approximately 375 herbs, shrubs and trees. Plants are native mostly to tropical and warm-temperate regions. Of most interest to the cut flower and bedding plant industries are the herbaceous annual and perennial species.

The following Lobelia species are most commonly grown:

Lobelia cardinalis L. (Cardinal Flower) is a perennial herb that grows to 100 cm in height. The scarlet, pink, or white flowers are 3 to 4 cm long. This species is commonly grown as a garden perennial and is also useful for cut flowers. It is native from New Brunswick to Minnesota, and south to Florida and east Texas. The chromosome number is 2n = 14.

Lobelia erinus L. (Edging Lobelia) is an annual or perennial herb growing mostly less than 20 cm in height. The species is native to South Africa and is used as a bedding plant. Flowers are about 1 cm long and come in various shades of blue, pink, and lilac, and also in white. Chromosome numbers are 2n = 28 or 42. Lobelia erinus is the most economically-important Lobelia species in the flower seed business.

Lobelia siphilitica L. (Blue Cardinal Flower) is a perennial herb that grows to 100 cm in height. The blue or white flowers are about 2 cm long. This species is native from Maine to South Dakota, and south to North Carolina, Mississippi, and Kansas. The chromosome number is 2n = 14. Lobelia siphilitica has been crossed with L. cardinalis (= L. x gerardii Chabanne & Goujonex Sauv.).

Lobelia splendens Willd. (= L. fulgens) is a perennial herb similar to L. cardinalis that is native to Mexico.

Lobelia tenuior R. Br. is an annual species to 60 cm in height, with flowers that are about 2 cm long. It is native to Australia and is occasionally grown as a potted plant. The chromosome number is 2n = 18.

Present Germplasm Activities:

Most of the breeding in recent times has been carried out by commercial seed companies using primarily L. cardinalis, L. erinus, and L. siphilitica. At present, there is no priority site within the NPGS for Lobelia. There are no Lobelia accessions listed in GRIN at the present time.

Status of Crop Vulnerability :

There is no current information on the status of L. erinus in South Africa or for L. tenuior in Australia. Additional investigation is needed to assess the vulnerability of indigenous populations for these two species. The two American species, L. cardinalis and L. siphilitica, are widespread in their native habitats and do not appear to be threatened.

Germplasm Needs:
A. Collection - Emphasis should be placed on collecting material from indigenous populations in South Africa, Australia, and North America. Considering the vast number of Lobelia species that have been discovered, it should be possible to find additional species that may be worthy of cultivation and/or useful in breeding.

B. Evaluation - Plant introductions should be screened in a cool climate region. However, it would be very useful to discover some heat-tolerant species or biotypes.

C. Enhancement - Plant introductions should be systematically screened for traits of horticultural interest, including mature plant height, branching, days to flowering, flower color, and heat tolerance. It is probable that most of the germplasm enhancement will be done by the private sector, but it would be desirable for one of the AES or PI stations to develop a small project with Lobelia.

D. Preservation - Lobelia is strongly cross pollinated, and therefore accessions will need to be isolated during flowering in order to maintain seed purity.

Recommendations:

Germplasm of commercially-important and new species needs to be collected, evaluated at various locations, and maintained at a location that meets the environmental requirements for the species. Lobelia is becoming a more important floricultural crop, both in the flower seed business and in cut flower markets. The estimated annual seed sales for Lobelia worldwide is approximately 2 million dollars (wholesale).

Researchers that may be contacted for additional information:

D.G. Holden, Waller Flowerseed Co., Guadalupe, CA
D.G. Lemon, Oglevee Ltd., ConnellsviBe, PA

Lobelia Synopsis Prepared by:
D.G. Lemon, Oglevee Ltd., Connellsville, PA

PELARGONIUM (Geraniaceae)
Introduction:
The genus Pelargonium consists of approximately 250 species of subshrubs, herbaceous perennials, and annuals. The center of diversity of the genus is South Africa, but a few species are found in tropical Africa, eastern Asia, and Australia.

The most important types that are grown as floricultural crops are the Zonal Geranium (P. x hortorum L.H. Bailey), Ivy Geranium [P. peltatum (L.) L'Herit.], and Regal Pelargonium (P. x domesticum L.H. Bailey). The Zonal Geranium is a complex group of hybrids derived from crosses between P. inquinans (L.) L'Herit. and P. zonate (L.) L'Herit. Zonal Geranium and Ivy Geranium are used extensively as bedding plants, and their wholesale value in the United States was about $157 million in 1993. Regal Pelargoniums have a complex ancestry, and are probably dervived from P. cucullatum (L.) L'Herit., P. fulgidum (L.) L'Herit., P. grandiflorum (Andrews) Willd., and other species. Regals are used primarily as a potted flowering plant.

Present Germplasm Activities:

Most of the breeding of this crop is being done by private companies, including Ball FloraPlant (West Chicago, IL and Nipomo, CA), Goldsmith Seed Co. (Gilroy, CA), and Oglevee Ltd. (Connellsville, PA and Lompoc, CA). The Pennsylvania State University (University Park, PA) has been active in Pelargonium breeding for many years. Several universities perform evaluation trials of commercial cultivars.

Status of Crop Vulnerability:

Indigenous populations of most Pelargonium species appear to be well protected in South Africa. The level of genetic diversity in cultivated Pelargonium germplasm is unknown.

Commercial cultivars of Pelargonium exhibit several shortcomings. More heat tolerance needs to be incorporated into the Ivy Geranium and Regal Pelargonium. Resistance to major pests needs to be incorporated, e.g., whitefly resistance in the Regal Pelargonium and tobacco budworm resistance in the Zonal Geranium. Many Pelargonium species are not suited for use as floricultural crops and are grown by hobbyists.

Germplasm Needs:

A. Collection - Collection of Pelargonium germplasm from wild populations is not a high priority. Presently, extensive collections of Pelargonium species are maintained at the National Botanic Gardens of South Africa (Kirstenbosch) and University of Stellenbosch. There is also a small collection of species at the University of California (Irvine campus) and Cornell University (Ithaca, NY). However, it is desirable to have seed accessions of Pelargonium species within the NPGS, and especially those species that are progenitors of the Zonal Geranium, Ivy Geranium, and Regal Pelargonium.

B. Evaluation - Breeders need to incorporate more heat, disease, and insect resistance into cultivated material. Therefore, screening accessions for heat and pest resistance would be valuable. Research on flower color transformation would also be of value.

C. Enhancement - Enhancement of Pelargonium germplasm by NPGS personnel is a low priority activity.

D. Preservation - Seeds of Pelargonium species need to be preserved within the NPGS.

Recommendations:

Priority of Actions - Acquire seeds of Pelargonium species that are the progenitors of the Zonal Geranium, Ivy Geranium, and Regal Pelargonium, and evaluate the accessions for heat and pest resistance. Germplasm exhibiting novel traits and/or pest resistance should be increased and made available to breeders.

Researchers that may be contacted for additional information:
D.G. Lemon, Oglevee Ltd., Connellsville, PA
R.Craig, The Pennsylvania State University, University Park, PA

Pelargonium Synopsis Prepared by:
D.G. Lemon, Oglevee Ltd., Connellsville, PA

PETUNIA (Solanaceae)

Introduction:

The genus Petunia is comprised of approximately 30 species of annual or perennial herbs. Their center of diversity is South America, with the majority of species native to Argentina, Brazil, Paraguay, and Uruguay. The Brazilian states of Parana, Rio Grande do Sul, and Santa Catarina are particularly rich in Petunia species. One species, P. parviflora, extends from South America northward to Cuba, Mexico, Texas, Arizona, Florida, California, and New Jersey.

The early literature concerning taxonomy and nomenclature is confusing and contradictory, and disagreement still exists today. There have been no recent studies on the ecology and evolution of the genus Petunia. Generally, four species are considered to be the parents of the Garden Petunia [= P. x hybrida Hort. Vilm.-Andr.]: P. axillaris, P. inflata, P. parodii, and P. violacea. These four species have n= 7 as the chromosome number, whereas P. parviflora has n = 9 as the chromosome number. Petunia axillaris and P. parodii are white-flowered species, with P. parodii having a much longer corolla tube. Petunia inflata and P. violacea have magenta (mallow purple) flowers; some taxonomists do not consider these two species to be distinct and have grouped them together as P. integrifolia var integrifolia (l). Petunia parviflora has small flowers and succulent-like foliage, and is generally used as a rapid-growing annual ground cover or hanging basket plant.

In 1990, petunia had a wholesale value of $124.3 million for plant producers of $10,000 or more in gross sales. The 1991 wholesale value of petunias was $113.3 million for plant producers of $100,000 or more in gross sales. Petunia ranks second in importance among bedding plants produced in the United States and comprises approximately 12.8% of the total crop mix grown by bedding plant producers.

Present Germplasm Activities:

Most breeding activities are conducted by private companies, including Bodger Seeds, Ltd (Lompoc, CA), Goldsmith Seeds Inc. (Gilroy, CA), PanAmerican Seed Co. (Elbum, IL), Sakata Seed Corp. (Yokohama, Japan), S & G Seeds (Enkhuizen, Holland), and Takii & Company, Ltd. (Kyoto, Japan), and these companies mainly work with P. x hybrida.

The NPGS priority site for Petunia germplasm is the Northeast Regional Plant Introduction Station (NRPIS) at Geneva, NY. Five species accessions (two P. axillaris and three P. integrifolia) and 96 P. x hybrida accessions (made up of line-bred and hybrid cultivars) are stored at NSSL. Many of the NSSL accessions are 20 to 30 years old and are declining in viability.

Status of Crop Vulnerability:

The status of indigenous populations of Petunia is unknown because there have not been any collecting expeditions for several years. Because few species form the genetic base of present-day cultivars, the genetic diversity could be considered to be low even though there are probably 300+ cultivars presently in cultivation. Currently, the major shortcomings of the crop are disease susceptibility and poor field performance during rainy weather. Commercial cultivars vary in their susceptibility to Alternaria, Botrytis, Phytophthora, Pythium, Rhizoctonia, and Sclerotinia.

Germplasm Needs:

A. Collection - Emphasis should be placed on collecting material from indigenous populations. The collection of hybrid cultivars should be a low priority, but the collection of line-bred cultivars should be second priority to collecting indigenous species. Many of the old line-bred cultivars are being lost but do contain considerable diversity.

B. Evaluation - Accessions should be evaluated for the following traits: growth habit; plant vigor; foliage color; flower size, color (limb and throat), and substance; fertility and self-compatibility; and resistance to disease, slugs, and air pollution. Novel growth habits, flower forms, and flower colors should be noted.

C. Enhancement - Germplasm enhancement activities should be subordinate to germplasm collection, evaluation, and preservation.

D. Preservation - The majority of Petunia germplasm used in plant improvement programs is maintained by private seed companies. NPGS should emphasize the collection and maintenance of true-to-type populations for Petunia species and older line-bred cultivars.

Recommendations:

The first priority should be the collection of the important Petunia species from indigenous populations in order to preserve the wild germplasm for plant improvement programs. Secondly, the number of NPGS accessions should be greatly increased for line-bred cultivars and greatly decreased for hybrid cultivars. Hybrid cultivars are easily obtained from commercial firms. Thirdly, the collected material should be thoroughly evaluated for disease resistance and horticultural traits.

Researchers that may be contacted for additional information:

L.C. Ewart, Michigan State University, East Lansing, MI
E. Leue, PanAmerican Seed Co., Elbum, IL

Petunia Synopsis Prepared by:
L.C. Ewart, Michigan State University, East Lansing, MI

SPATHIPHYLLUM (Araceae)

Introduction:

The genus Spathiphyllum consists of about 35 species of tropical perennial herbs. Spathiphyllum are grown commercially as potted ornamental foliage plants and, in dollar value, consistently rank in the top 10 among all foliage plants grown. They are especially valued for their large showy white spathes that subtend the inflorescence. Commercial cultivars are mostly propagated asexually.

Present Germplasm Activities:

Germplasm enhancement and breeding research on Spathiphyllum are being conducted by the Florida AES at Apopka, Florida. Program goals include breeding for disease resistance, improved branching, foliar variegation and continuous bloom cycle. The NPGS priority site for Spathiphyllum germplasm is CR-MIA (Miami, FL). The NPGS does not contain any Spathiphyllum accessions at the present time.

Status of Crop Vulnerability:

The genetic diversity of approximately 25 major spathiphyllum cultivars grown is quite small. Most cultivars are derived from S. 'Mauna Loa'. 'Mauna Loa' was a seed-propagated cultivar of unknown origin, until the mid 1970's when tissue culture became a major propagation method. Improved forms of 'Mauna Loa' were obtained from seedling populations or mutants found among cultured plants. Hybrids of 'Mauna Loa' with S. wallissii produced some important cultivars and thus enhanced genetic diversity. Spathiphyllum wallissii apparently was closely related to 'Mauna Loa' as the hybrids are fully fertile and intercross readily. No other Spathiphyllum species have been incorporated into commercial cultivars, although attempts are currently underway.

Almost all commercial cultivars produced are asexually propagated via tissue culture and are susceptible to Cylindrocladium spathiphylli, a fungal stem and root rot for which there is no effective chemical control. Two collected species, S. florabundum and S. cannifolium have resistance to this fungal disease. However, genetic barriers prevent hybridization of these species with commercial cultivars. Therefore, collection of wild germplasm may find other sources of resistance that can be introduced into commercial cultivars.

Most commercial Spathiphyllum cultivars are seasonal bloomers (January-June) and require chemical treatment to flower at other times of the year. Collection of germplasm with year-round flowering patterns could eliminate the need for chemical treatments.

Germplasm Needs:

A. Collection - Emphasis should be placed on material collected from indigenous populations throughout the tropics. New germplasm of S. florabundum and S.cannifolium would be extremely useful to breeders for conferring disease resistance and recurrent flowering into new cultivars.

B. Evaluation - Plant introductions should be evaluated for resistance to Cylindrocladium, growth habit, leaf shape and size, degree of branching, flower size and flowering cycle.

C. Enhancement - There is a breeding program at the Florida AES, but additional research is needed to conduct screening for disease resistance and find new sources for resistance.

D. Preservation - The majority of Spathiphyllum germplasm is preserved by private plant collectors or botanic gardens. Maintaining germplasm is difficult because plants become rather large and require periodic asexual propagation (division). In addition, plants should be kept in a shaded greenhouse or similar enclosed structure and must be grown at high minimum temperatures.

Recommendations:

Priority of Actions - Germplasm of the important Spathiphyllum species (S. florabundum and S. cannifolium, plus new species not in cultivation) should be collected from indigenous populations in order to preserve wild material. Collected material should be disseminated to breeders as use in plant improvement programs.

Researchers that may be contacted for additional information:

R.J. Henny, University of Florida, Apopka, FL

Spathiphyllum Synopsis Prepared by:
R.J. Henny, University of Florida, Apopka, FL

VERBENA (Verbenaceae)

Introduction:
The genus Verbena is comprised of approximately 200 species of annual or perennial herbs or subshrubs. The species are native mostly to tropical and subtropical North and South America. Verbena is increasing in economic importance, and plants are grown in annual and perennial gardens and in hanging baskets. The domestic wholesale value of verbena seeds and plants is estimated at about $1 million annually.

Several Verbena species and hybrids are cultivated. They include the following:

Verbena bipinnatifida (Dakota Vervain), native to North America, is a prostrate perennial that grows about 40 cm tall and has dense, corymblike spikes of lilac-purple flowers.

Verbena bonariensis, native to South America, is an upright annual or perennial that grows about 120 cm tall and has dense spikes of lilac flowers (n = 14).

Verbena canadensis (Rose Verbena), native to North America, is a perennial with creeping, decumbent, or ascending stems and spikes with reddish-purple, lilac, rose, or white flowers (n = 15).

Verbena x hybrids (Garden Verbena) is a variable species that is assumed to be an interspecific hybrid between V. peruviana and other species (n = 10, 20). The majority of the Verbena cultivars sold commercially are derived from this hybrid. The species is a decumbent or creeping perennial (but grown mainly as an annual) with flattish, corymblike spikes with pink, red, white, blue, yellow, purple, or bicolored flowers.

Verbena peruviana, native to Argentina, Brazil, and Chile, is a perennial (but grown mainly as an annual) with procumbent stems and corymblike spikes with scarlet or crimson flowers (n = 5).

Verbena rigida (Vervain), native to Argentina and Brazil, is a perennial that grows from 30 to 60 cm in height. with erect or ascending stems and spikes with purple or magenta flowers (n = 21).

Verbena tenuisecta (Moss Vervain), native to South America, is a perennial that grows to 25 cm in height, and has decumbent or ascending stems and corymblike spikes with blue, purple, violet or lilac flowers.

Present Germplasm Activities:

Most breeding work is being done in the private sector using a very limited germplasm base. The NPGS priority site for Verbena is NCRPIS (Ames, IA). The NCRPIS Verbena collection contains four accessions (V. halei, V. hastata, V. officinalis, and V. urticifolia), and the NSSL maintains seed of 19 Verbena cultivars.

Status of Crop Vulnerability:

Most of the North American species have a widespread distribution and are therefore not threatened. In regard to the South American species, the status of indigenous populations is not known.

Germplasm Needs:

A. Collection - Emphasis should be placed on re-collecting the known South American species, and also collecting germplasm of previously unknown species.

B. Evaluation - Accessions should be evaluated by NPGS personnel and also by private companies.

C. Enhancement - It should be very useful if AES or NPGS personnel could handle a small project with Verbena. Certainly more work needs to be done on improving disease resistance and seed germination for this crop.

D. Preservation - Verbena tends to be predominantly self-pollinated so isolation should not be a major problem. The small-flowered species self, but many North American species do outcross and will hybridize with related species.

Recommendations:

Germplasm of known and new Verbena species needs to be collected from South America, evaluated at several locations, and maintained in an area with a dry, mild climate.

Researchers that may be contacted for additional information:

D.G. Lemon, Oglevee Ltd., Connellsville, PA

Verbena Synopsis Prepared by:
D.G. Lemon, Oglevee Ltd., Connellsville, PA

ZANTEDESCHIA (Araceae)

Introduction:

The genus Zantedeschia, commonly referred to as callas, calla lilies and spring calla lilies, has six species and two subspecies of horticultural significance. They are all indigineous to southern Africa, primarily in the northern Transvaal range. Zantedeschia species and cultivars can be split into two groups: the Common Calla group consisting of Z. aethiopica, and the Spring Calla group consisting of the other five species.

The most familiar Zantedeschia species is Z. aethiopica, the Common Calla (2n = 32). The species is primarily used as a cut flower in wedding and funeral bouqets. The large spathe is pure white and up to 20 cm long and the bright yellow spadix is 6 to 10 cm long. Leaves are glabrous, immaculate (not spotted), usually broadly ovate, and supported by long, fleshy petioles. Rhizomes of Z. aethiopica tend to be more elongated or columnar than species in the Spring Calla group. The species is distributed beyond the winter rainfall area of the Cape, extending from the eastern coastal districts to Natal and the mountains of the Orange Free State, northern Transvaal, and Lesotho. It is often found in moist and marshy areas, and is less prone to bulb rots. Variations in type are not uncommon in cultivation. Occasional dwarf or fragrant types are discovered, such as 'Childsiana' and 'Onorata.' Other variations include types with green-white bicolored spathes, blush pink spathes, maculated leaves, and dormant types. Approximately two million bulbs (rhizomes) of Z. aethiopica are sold annually (worldwide).

The Spring Calla group (also referred to Colored or Miniature Callas) consists of the five remaining Zantedeschia species (2n = 32). The rhizomes tend to be flatter and wider than Z. aethiopica. Spring Callas are grown both for cutflowers and as potted plants, and have exhibited a worldwide increase in popularity during the past decade. Sales from California alone are three million bulbs annually, and worldwide sales are significant. Spring Callas are more difficult to grow than Z. aethiopica, primarily due to susceptibility to soft rots. Few barriers exist to hybridization between species within this group, resulting in a great diversity of flower colors and plant habits.

The Pink (or Red) Calla (Z. rehmannii) is the most suitable species for cultivation in pots. As a consequence, it is the main species used for breeding of pot-plant cultivars. Spathe color is commonly blush pink but can vary from almost white to deep purple. Leaves are lanceolate, up to 40 cm long, 2 to 7 cm wide, immaculate, and glabrous. The species is native to rocky slopes and forest margins at medium to high altitudes from Harrismith in northern Natal, through Swaziland, and extending to southern and eastern Transvaal. Pink Calla has intermediate susceptibility to Erwinia soft rot and moderate tolerance to Dasheen Mosaic Virus (DMV).

The Golden (or Yellow) Calla (Z. elliottiana) is a robust species with lemon-yellow to gold, orange or rusty red spathes. The orbicular-ovate, deeply cordate leaves are up to 27 cm in length and nearly as broad, with many translucent maculations (spots). Golden Calla produces large rhizomes, is moderately floriferous, and is important economically as a cut flower. The type is known only from plants in cultivation; there are no known specimens of this species in the wild. Golden Calla is moderately tolerant to DMV but is the most susceptible Zantedeschia species to Erwinia soft rot.

Zantedeschia pentiandii is superficially similar to Z. elliottiana but differs in that the leaves are usually immaculate, oblong-elliptic to oblong-lanceolate, hastate, and up to 35 cm long and 15 cm wide. The spathe is lemon-chrome to deep yellow, usually with a purple blotch at the base of the spadix interior. Although vigorous, rhizome growth is slower and plants are less floriferous than Z. elliottiana. However, the species has distinctly greater resistance to Erwinia soft rot, giving greater economic importance to the species in the future. The species commonly occurs in rocky terrain and by small streams on grassy slopes, and is restricted to the Mapoch region of the eastern Transvaal.

Zantedeschia jucunda is little known in cultivation but is similar to Z. pentlandii in plant size and flower color. Leaves, however, are similar to Z. albomaculata, being triangular-hastate, densely maculate, 17 to 30 cm long, and 5 to 15 cm wide. The spathe is golden-yellow with a purple blotch. The species is restricted to the Magnet Heights region of the Lulu Mountains, Sckhukhuniland. The responses of Z. jucunda to DMV and Erwinia soft rot are not known.

The Spotted Calla (Z. albomaculata) has three recognized subspecies whose aggregate distribution extends through Natal, Lesotho, Swaziland, and the eastern Transvaal, and continues north into Zambia and Angola. The species is generally characterized by vigorous, strongly maculate leaves that are 40 to 75 cm in length. The 2.5- to 17-cm long spathes range from white to cream, pale yellow, or coral in color. Cultivated plants exhibit good rhizome development. The subspecies exhibit differences in leaf shape, maculation intensity, and flower color. Zantedeschia albomaculata ssp. albomaculata has conspicuously maculate, triangular, oblong-hastate leaves and white (rarely pink or pale yellow) spathes. Zantedeschia albomaculata ssp. macrocarpa has sparsely maculate leaves, broad creamy-white spathes, and large fruit. Zantedeschia albomaculata ssp. valida is a robust plant to 80 cm tall, with immaculate leaves and ivory-to cream-colored spathes. Spotted Calla demonstrates the highest tolerance to Erwinia soft rot within the genus Zantedeschia, but low tolerance to virus infection. This species may be a potential source of genes controlling disease resistance, vigor, and flower color.

Present Germplasm Activities:

Current breeding in the United States is primarily limited to Golden State Bulb Growers (GSBG), formerly Brown Bulb Ranch, located in the Monterey Bay area of central California. GSBG's improvement efforts began nearly half a century ago and have focused on the Spring Calla group. Since 1988, GSBG has supported a breeding program encompassing most species of the Spring Calla group and, to a lesser extent, the Common Calla. Research at universities and other public institutions is concentrated on cultural problems and not on genetics or breeding.

New Zealand researchers have been involved with Zantedeschia improvement since the 1930s. In the 1980s, the New Zealand calla producers coordinated and funded an organized breeding effort under the auspices of the International Calla Association (ICA). The ICA has exerted less influence in recent years and has been surpassed by several small firms. We are not aware of any private companies or public institutions in New Zealand, Australia, or South Africa that are preserving Zantedeschia germplasm. There are no Zantedeschia accessions within the NPGS, nor has an NPGS priority site for Zantedeschia germplasm been designated.

Status of Crop Vulnerability:

South Africa is the center of genetic diversity for Zantedeschia. The current status of indigenous populations is not known. However, Z. elliottiana is not currently found in the wild, and this is probably true of other local variants due to habitat erosion and collection.

Disease susceptibility, particularly to Erwinia soft rot, can lead to severe plant losses at virtually any time of year. The pathogens inciting soft rot are ubiquitous, are primary as well as secondary pathogens in dormant and actively growing rhizomes, and cannot be adequately controlled by chemical means. The Spring Calla group is highly susceptible, although variation exists for tolerance. Some Z. aethiopica clones demonstrate moderate to high resistance, and efforts are being made to transfer resistance from this species to the Spring Calla group. Virus infection can also devastate calla plantings. The major viruses of Zantedeschia are DMV and (to a lesser extent) Tomato Spotted Wilt Virus (TSWV). Genetic variation appears to exist for DMV symptom expression but not for true resistance. The primary fungal diseases are root rots incited by Phytophthora and Rhizoctonia, and leaf spots incited by Alternatia and Cercospora.

Germplasm Needs:

Current enhancement programs rely on variation from a relatively narrow genetic base, i.e., commercial cultivars. It would be highly desirable to broaden the genetic base by incorporating wild germplasm from several Zantedeschia species.

A. Collection - Exploration and collection should be the primary activity of the NPGS. It should focus on the Transvaal region of South Africa and extend beyond the Transvaal for some species. All Zantedeschia species should be collected. However, due to the need for greater disease resistance and improved plant habit, special interest should be placed on Z. albomaculata (white and blush spathes), Z. pentlandii (yellow spathes), and Z. rehmannii (pink spathes). Emphasis should be placed on selecting clones that exhibit novel traits, such as a unique spathe color or plant habit. Since Zantedeschia species are primarily autogamous, plant collecting could be performed with minimum impact to natural populations by tagging flowering plants in situ and returning later to collect mature seed. Alternatively, intact plants (rhizomes) may be collected during one trip.

B. Evaluation - The primary limitation to commercial production of Zantedeschia is disease susceptibility. Therefore, screening for disease resistance on new and existing accessions is needed. Currently, little or no disease resistance screening programs exist. Floriferousness in relationship to rhizome size also should be evaluated. Simple descriptive notes on plant habit and spathe characteristics (color, shape, and size) should be recorded.

C. Enhancement - Private industry would be responsible for all enhancement and breeding activities. Since commercial cultivars are clonally propagated, some novel selections from wild germplasm may not need additional breeding and would only require mass propagation before release.

D. Preservation - Zantedeschia rhizomes are not difficult to maintain if they protected against soft rot or virus infections. Rhizomes are best maintained in pots and grown annually. Seed is relatively large (1 to 3 mm) and will remain viable for a minimum of 5 to 7 years if stored at low humidity and temperatures near 0oC. Minimum isolation of plants is needed because Zantedeschia is primarily autogamous. The number of seeds per inflorescence ranges from 6 to 50. True species, their variants, and many cultivars are relatively true-breeding; therefore, much of the germplasm may be preserved as seed stocks. Plants begin flowering within 2 to 3 years from seed sowing. Zantedeschia germplasm should be maintained in a region with a mild temperate climate, and preferably inside a greenhouse or screenhouse. Good sanitation practices should be exercised throughout crop growth. Due to the relative ease of germplasm preservation, NPGS holdings should amount to 15 to 50 accessions per species. Non-stable interspecific mixes could be maintained in small populations of 40 to 70 plants. Current cultivars could be maintained with 7 to 10 accessions.

Recommendations:

Wild germplasm should be collected, with emphasis on obtaining unusual as well as typical plants from several populations of each species and subspecies. Non -destructive collecting methods are somewhat more costly but are possible. Accessions should be screened for disease resistance. Preservation and descriptive notes on plant traits are relatively straightforward tasks.

Researchers that may be contacted for additional information:

P. Beckman, Golden State Bulb Growers, Watsonville, CA

Zantedeschia Synopsis Prepared by:
P. Beckman, Golden State Bulb Growers, Watsonville, CA

ZINNIA (Asteraceae)

Introduction:

The genus Zinnia consists of approximately 20 species of annual or. perennial herbs or low shrubs, all indigenous to the western hemisphere. All of the species except Z. peruviana are restricted to North America. The center of genetic diversity for Zinnia is Mexico.

Three species of Zinnia are cultivated widely and are grown commercially as bedding plants and/or cut flowers: Z. Wolacea Cav. [syn. Z. elegans Jacq.), Zinnia haageana Regel., and Zinnia angustifolia H.B.K. (syn. Z. linearis Benth.). The most widely cultivated species is Z. violacea, a herbaceous annual that is grown for its large, showy inflorescences and diversity of ray floret colors and petal forms. Plants are erect, 9-200 cm in height, sparsely branched, with large ovate to lanceolate leaves; cultivated forms have one to several whorls of ray florets. It is distributed from Sinaloa and Durango to Guerrero at elevations from 600 to 1800 meters, and flowers from March to November. The species is endemic to openings in woodlands, grassy and weedy places, old fields, roadsides, and ditches, in open oak forest or tropical deciduous forest. Landrace types are widely grown in Mexican household gardens. The chromosome number is n = 12.

Zinnia haageana is a herbaceous annual with an erect or decumbent habit, ranging up to 60 cm in height, with lanceolate leaves, and 2-4.5 cm wide inflorescences with a single whorl of solid or bicolored ray florets. Cultivated forms often have several whorls of ray florets. The species is found from Jalisco to Guerrero at elevations from 900 to 2000 meters, and flowers from July to November. It is endemic to grasslands, grassy or rocky hills, wet meadows and fields, roadsides, and disturbed habitats. The chromosome number is n = 12.

Zinnia angustifolia is a herbaceous annual exhibiting an erect or decumbent habit. Plants are 20-40 cm in height, profusely branched, with linear to oblong-elliptic leaves and masses of small inflorescences (1.5-3.5 cm in diameter) with orange or white ray florets in a single whorl. The species ranges from Sonora and Chihuahua to Michoacan at elevations from 60 to 2100 meters, and flowers from July to January. It is endemic to rocky or grassy hills, lava-flows, clearings and woodland openings, often in disturbed habitats, in oak or oak-pine forest, tropical deciduous forest, and savannahs. The chromosome number is n = II.

Zinnia violacea is a major seed packet item in North America, but represents only = 1 % of the total plants produced in a typical bedding plant operation. Commercial growers attribute the low percentage of Z. violacea grown as bedding plants to high seed costs and difficulties in producing high-quality plants. Production difficulties include disease susceptibility, nonuniformity of flowering at sales time, and excessive plant height. Improvements in disease resistance, uniformity of flowering, plant habit, and seed yield are needed.

Present Germplasm Activities:

Germplasm enhancement on Zinnia is currently being conducted by the Massachusetts AES (Amherst, MA) and the Michigan AES (East Lansing, MI). The goals of the AES programs include improved disease resistance, enhanced branching, reduced leaf width (reduced leaf area), and novel flower colors/growth habits. The NPGS priority site for Zinnia is NCRPIS (Ames, IA). Activities at NCRPIS include collection, evaluation, and preservation of zinnia germplasm.

Status of Crop Vulnerability:

The status of indigenous populations of Zinnia was surveyed in a fall 1993 exploration to Mexico. In northern and central Mexico, Z. peruwana was extremely common in distrubed habitats, Z. violacea was cultivated in household gardens, and Z. haageana and Z. bicolor were occasionally found in grasslands and rocky scrubland. Other annual species were difficult to locate. Among the shrubby Zinnia species, Z. acerosa was distributed widely in creosote bush and thom scrub, Z. juniperifolia was restricted to mid-elevation slopes with juniper and pinion near Saltillo, and Z. citrea was relocated from the type locality.

The level of genetic diversity in commercial zinnia cultivars is unknown. Over 50 cultivars of Z. violacea are available commercially, including open-pollinated cultivars and F1 hybrids; most cultivars are diploid (2n = 24), although a few tetraploids (2n = 48) have been developed. Three open-pollinated cultivars of Z. haageana are available commercially, including two diploids (2n = 24) and one tetraploid (2n = 48). Three open-pollinated cultivars of Z. angustifolia var. angustifolia are sold commercially; they are ostensibly diploid (2n = 22).

In the United States, three pathogens incite moderate to severe epiphytotics within Z. violacea plantings: Alternaria zinniae Pape causing alternaria blight, Erysiphe cichoracearum DC. ex Merat causing powdery mildew, and Xanthomonas campestris pv. zinniae Hopkins & Dowson causing bacterial leaf and flower spot. Powdery mildew is the most serious disease of Z. violacea and Z. haageana in the United States, and susceptibility of Z. violacea cultivars to powdery mildew appears to be a major contributing factor to declining seed sales. Alternaria zinniae and Xanthomonas campestris pv. zinniae are seed-born pathogens and are thus a major concern for both seed producers and commercial growers. Commercial cultivars of Z. violacea are either highly susceptible or exhibit limited resistance to these three pathogens. Zinnia angustifolia var. angustifolia is highly resistant or immune to all three pathogens, and this species has been crossed with Z. violacea. The interspecific hybrids (= Z. marylandica) exhibit high levels of resistance to Alternaria zinniae and Erysiphe cichoracearum, and moderate to high levels of resistance to Xanthomonas campestris pv. zinniae. However, plants of Z. marylandica are less suitable than Z. violacea as a cut flower, primarily due to smaller inflorescences and fewer ray florets in the former. Identification of disease resistance within Z. violacea would be of considerable value.

Germplasm Needs:

A. Collection - Emphasis should be placed on material collected from indigenous populations. Currently, NCRPIS has 56 accessions of Zinnia (6 Z. angustifolia; 2 Z. grandiflora; 9 Z. haageana; 12 Z. peruviana; 9 Z. violacea; and 5 other species). In additon, NSSL holds 1 Z. angustifolia, 2 Z. peruviana, 4 Z. violacea, and 19 unidentified Zinnia species (primarily Z. violacea cultivars). The NPGS holdings should be expanded significantly to include approximately 15 accessions of each Zinnia species that is not in cultivation, and approximately 50 accessions for each of the economically-important species, i.e., Z. angustifolia, Z. haageana, and Z. violacea. Sources of resistance to Alternaria zinniae, Erysiphe cichoracearum, and Xanthomonas campestris pv. zinniae are needed in Z. violacea. Small-leaved populations of Z. violacea would be useful to breeders. Novel growth habits, flower forms, and flower colors are needed in Z. angustifolia, Z. haageana, and Z. violacea.

B. Evaluation - Plant introductions should be systematically screened for disease resistance and evaluated for the following characters: plant habit, leaf shape/size,degree of branching, flower diameter, shape/number of ray florets, and ray floret color.

C. Enhancement - There are breeding programs in progress at the Massachusetts AES and the Michigan AES, but more research is needed to identify new sources of disease resistance that can be used as germplasm in plant improvement programs. Germplasm enhancement activities at the NPGS priority site for Zinnia should be subordinate to collection, evaluation, and preservation of germplasm.

D. Preservation - The majority of the Zinnia germplasm used in domestic improvement programs is maintained by private seed companies. Within the NPGS, emphasis should be placed on developing and maintaining populations that are representative of the germplasm of an area rather on single plant collections. Zinnias are cross-pollinated and have a sporophytically-controlled self incompatibility (SI) system. Plant introductions thus require isolation during seed production in order to maintain purity, and several SI genotypes are needed for intercrossing within PIs.

Recommendations:

Priority of Actions - Germplasm of the important Zinnia species (Z. angustifolia, Z. haageana, and Z. violacea) needs to be collected from indigenous populations in order to preserve the wild material that still exists. Secondly, the NPGS holdings should be expanded to include accessions of each Zinnia species that is not under cultivation. The collected material needs to be thoroughly evaluated in replicated trials for horticultural traits. These accessions could then be used by breeders as germplasm in plant improvement programs.

Researchers that may be contacted for additional information:

T.H. Boyle, University of Massachusetts, Amherst, MA
L.C. Ewart, Michigan State University, East Lansing, MI
M.P. Widrlechner, USDA/ARS, NCRPIS, Ames, IA

Zinnia Synopsis Prepared by:

T.H. Boyle, University of Massachusetts, Amherst, MA
M.P. Widrlechner, USDA/ARS, NCRPIS, Ames, IA

VII. Priority Genera that are Currently Without a Synopsis:

Genus Family Number of Species: Center(s) of Diversity

Alstroemeria Alstroemeriaceae approx. 60; Brazil, Chile, & Peru
Aster Asteraceae 250-500; N. & S. America, Europe, Asia
Caladium Araceae approx. 15; tropical America
Euphorbia Euphorbiaceae > 1,600; W. Hemisphere (sp. of interest)
Kalanchoe Crassulaceae approx. 125; Africa & Madagascar