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Roh, M.S. and R.H. Lawson. 1990. New floricultural crops. p. 448-453. In: J. Janick and J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR.

New Floricultural Crops*

Mark S. Roh and Roger H. Lawson

  1. INTRODUCTION
  2. THE NEW CROPS PROGRAM
    1. Collection
    2. Propagation
    3. Production
    4. Production-Nationwide Evaluation
    5. Schedule for Production Trial
    6. Pre- or Post-production Physiology
    7. Distribution of Plant Material and Release of Cultural Information
    8. Consumer Education
  3. FINANCIAL SUPPORT
  4. RESEARCH RESULTS
  5. LIST OF NEW CROPS FOR EVALUATION
    1. Pot Plants
    2. Cut Flowers
    3. Bedding Plants
  6. CONCLUSION
  7. REFERENCES
  8. Fig. 1

INTRODUCTION

The definition of new crops can be: a newly discovered genera or species; newly introduced cultivars of plants grown in earlier years, but forgotten or without complete cultural information; plants that are cultivated in foreign countries but have not been introduced in the United States; or crops that can be produced with new production technologies that can enhance crop quality and shorten the total production time.

New crops research programs in The Netherlands (Noordegraaf 1987) and Denmark (Christensen and Fries 1987) have expanded the range of new plant materials available in the European market. A similar program was initiated for the United States (Armitage 1986, Roh and Lawson 1987b). Introduction of new crops requires identification, exploration and collection of new plants (Klougart 1987), with interesting characteristics that may be economically important. Hybridization and selection from a breeding (Wilfret 1987) program or introduction of new cultural technology (Noordegraaf 1987, Roh and Lawson 1987b) are important steps in the introduction of a new crop. To meet the increasing demand by growers and consumers for new crops in the U.S., the Florist and Nursery Crops Laboratory initiated a program of germplasm development in 1982. A cooperative agreement was signed between the American Floral Endowment, the Society of American Florist (SAF), and the USDA in 1984 to provide additional financial support for the program.

THE NEW CROPS PROGRAM

The overall scheme is diagrammed in Fig. 1.

Collection

The Laboratory collection includes many genera or species of native Australian plants including Correa, Chamelaucium, and Anigozanthos (kangaroo paw); Gesneriaceae such as Achimenes and Columnea from specially growers; Centradenia and Coprosma from Denmark; and new cultivars of Eustoma and Clematis for pot plant culture from Japan. When certain genera and species are identified as potential new crops, additional species or cultivars are secured to increase the germplasm base. This is important since selections or hybrids from one area of the world may not have the same requirements for flowering as plants of the same genus developed at other locations. For example, two clones of Reinwardtia indica have different critical photoperiods for flower induction (Christensen 1988).

Propagation

Generally less than 10 propagules are collected and it takes approximately a year to build enough stock plants for the initial experimentation. During propagation and early growth and development, the rate and the ease of propagation as well as plant statue are evaluated. Observations are made on the compact and dwarf appearance of plant, time of flowering, and susceptibility to disease. Care must be taken not to eliminate potentially important germplasm. Flowering may be erratic under natural greenhouse growing conditions, and further evaluation may require controlled light and temperature studies. For example, Aeschynanthus speciosus Hook. does not flower uniformly and extensive research was required to determine factors necessary for uniform and controlled flowering in year-round production (Gertsson 1987, Roh et al. 1988, Welander 1984).

Production

Following propagation and an initial period of observation, investigations of growth media/nutrition, growth regulator treatments, and light and temperature effects are initiated. A major factor to consider while assessing production capability is the forcing period. From the time the grower places the rooted plant in the greenhouse bench, a maximum production time of 18 weeks will allow a turnover of three to four crops a year. Should the plant be excluded if more than 18 weeks are required? The total production time of Eustoma grandiflorum Griesb. from seed sowing to flowering requires about seven months (Halevy and Kofranck 1984, Roh and Lawson 1984a, Tsukada et al. 1982). On the basis of cropping time, Eustoma might be excluded from the program, although post-production longevity is excellent. However, plug production technology has enabled greenhouse growers to shorten cropping time to 15 to 17 weeks (Roh and Lawson, 1984a).

Production-Nationwide Evaluation

After an initial production trial in the laboratory, cultural information is released (Griesbach 1985, Lee et al. 1988, Roh and Lawson 1984a, b, 1987b). Evaluation of the same production protocol is then tested at various locations under diverse environmental conditions. Development of a systematic and well coordinated national program on the new crop project is vital for the success of the total introduction program. The nationwide system described by the Florist and Nursery Crops Laboratory for new crop introduction requires support from all sectors of industry and from research scientists. Based on the criteria for selection and the nationwide evaluation program, recommendations can then be made for production of specific cultivars in different areas of the country.

Schedule for Production Trial

The time required for a regional and national production trial may vary depending on the nature of the new crop. The time required also depends on the extent of the information to be developed. We project a maximum of five years if a plant, like Eustoma, is relatively new or has not been investigated extensively A maximum of two to three years may be sufficient for crops like Coprosma and Cupressus that have been commercialized on a limited scale or previously introduced in other countries.

Pre- or Post-production Physiology

Post-production physiology can be an important factor in determining which plants should or should not be maintained in the program. However, the post-production characteristics cannot be used to screen the plant material at the beginning of the program. Coprosma 'Coppershine' initially showed an undesirable yellowing and shedding of leaves, but by maintaining a tissue nitrogen content higher than three percent, plants can be transferred from a greenhouse to a home environment without acclimatization. Tiny flower buds of Eustoma will not open on stems after harvest nor will a full purple or pink color develop when cut stems or potted plants are placed in a low-light intensity. This problem requires further study to extend useful post-production life of the crop.

Distribution of Plant Material and Release of Cultural Information

Following the research phase, a potential new crop is distributed to selected growers in the United States so that the plants can be tested and evaluated under commercial conditions. Plant material is distributed to the cooperators with complete instructions on how to handle the crop for proper evaluation. Cultural and handling information is then published in grower periodicals. Examples include articles on Gerbera (Roh and Lawson 1984b), Eustoma (Roh and Lawson 1984a), Anigozanthos (Roh and Lawson 1987a) and Phalaenopsis orchid 'Toyland' (Griesbach 1985, Lee et al. 1988). Research results, displays of plant material and posters are also presented at growers meetings and trade shows.

Consumer Education

At the time of the introduction of plant material and cultural information, consumers and the general public must be informed of a planned new crop introduction. Growers, wholesalers, and retailers should all receive advance information prior to introduction. If consumers are not properly informed by the retailer at the end of the marketing channel or by other media sources, the demand at the time of an introduction may be so low that the new plant may be a disappointment to the grower, and the economic potential of the crop may not be realized.

FINANCIAL SUPPORT

New crops research in the Florist and Nursery Crops Laboratory was initiated with support from the USDA Small Farms Program and by a grant from the Fred C. Gloeckner Foundation in 1982. In 1984, the program was expanded with a contribution from industry members of the SAF and the SAF Growers Division through the American Floral Endowment. The annual contribution from industry is matched by the Administrator of the USDA, Agricultural Research Service. Program sponsors from industry have formed an advisory committee that assists in locating and securing new plants, suggests research directions, and aids in market analysis for the new plant material to be released. The advisory committee meets twice a year, once at Beltsville to observe new plant material and advise in the selection of plant candidates for further experiments. The advisory committee members are given up-to-date information on new plant material collected and results of past research.

RESEARCH RESULTS

Eustoma grandiflorum Griesb. Seed propagation (Tsukada et al. 1981) is the best method to start a crop although tissue culture (Semeniuk and Griesbach 1987) and rooting of cuttings (Roh et al. 1986a) are also possible. Seeds germinate within 15 days at 25°C. During the first 60 to 90 days after germination, temperatures above 25°C should be avoided to prevent heat stress. The optimum temperature is considered near 10° to 15°C. Seedlings should be transplanted before the stem elongates, and root disturbance should be minimized to prevent wilting when the plants show visible buds. More than 60 days of 16 hours of long days are required to accelerate flowering by about 15 to 25 days (Tsukada et al. 1981).

Most commercial cultivars are tall, cut flower types that require the application of growth retardants for pot plant production (Roh and Lawson 1984a, Tjia and Sheehan 1986). In the Florist and Nursery Crops Laboratory, genetic dwarf selections were obtained from tissue culture and multiplied through seed propagation without losing the dwarf characteristics (Griesbach et al. 1988).

Chamelaucium uncinatum Schauer. Stem tip cuttings are propagated between October and May without difficulty. Rooting hormone, rootone or 1600-3000 ppm IBA treatments enhance rooting of the cuttings (Whitton et al. 1988). Rooted plants grow slowly and may require up to 4 to 5 months before an inductive treatment for flowering can be given. Liquid feeding at 200 to 400 ppmN or one gram of slow release fertilizer such as 14N-6P-8K Osmocote per 10 cm pot will ensure optimum vegetative growth. When shoots are 5 cm long, 40 days at 18° to 20°C with 10 hours of short day or 3 to 4 weeks of 8 hours of short day at 24deg./16deg.C initiated flower buds (Shillo et al. 1985). Keeping quality as a pot plant is excellent.

Correa 'mannii' Andr. Stem tip cuttings root easily with 1500 ppm IBA treatment. Nutrition requirements are similar to Chamelaucium However, Correa is a long day plant requiring at least 40 days of 16 hours of long days at 18°C. Keeping quality as pot plant is good, lasting about 20 days after anthesis.

Achimenes and Achimenantha. Selected Achimenes longiflora D.C. hybrids and one Achimenantha hybrid were evaluated for forcing during winter. Due to a dormancy that lasts more than 3 months in Achimenes, and 5 months in Achimenantha, tissue culture propagation was employed to maintain stock plants. Scale pieces were successfully used as an explant source, and flowering plants were obtained in 80 to 100 days, depending on the season, without mutation (Roh and Wocial 1988). To avoid dormancy (Deutch 1974), rooted cuttings should be forced with 16 hours of long days from high irradiant discharge lamps.

Gerbera jamesonii Hook. Tissue culture and seed propagated gerbera selections were evaluated. Gerbera required 8 to 12 hours of photoperiod at 15° to 18°C for 40 days to promote flowering (Roh and Lawson 1984b). Some Happipot strains did not require short days. Seed gerbera require higher temperatures (21°C) and possibly short days to increase the number of flowers. Osmocote and liquid fertilizer treatments are required for quality crop production.

Aeschynanthus speciosus Hook. Techniques for year-round flowering of Aeschynanthus speciosus and hybrids are being investigated. Rooted cuttings of Aeschynanthus speciosus, flowered when rooted cuttings were obtained from stock plants grown with a high nutritional regime (Roh et al. 1988). Some other hybrids flowered earlier under high temperature, long day, and high light intensity conditions (Gertsson 1987, Welander 1984, Zimmer 1972). Recent studies indicate that rooted cuttings from stock plants grown at 18deg./17°C day/night, flowered earliest as compared to higher temperatures.

Anigozanthos. Kangaroo Paw is propagated by tissue culture or division (Ellyard 1978). Young plants should be grown at least 8 weeks out of tissue culture before an inductive treatment for flowering is given. Some selections do not require low temperature treatments, 13°C for 6 to 8 weeks, although most of the hybrids tested require low temperature treatments for flowering (Roh and Lawson 1987a). When the temperature is higher than 21°C, flowering is completely inhibited when plants are grown under short day conditions. Some flowering occurs under long day conditions, even at temperatures above 18°C. Temperature is a controlling factor for flowering (Motum and Goodwin 1987).

Lilium elegans Thunb. Research has focused on flower bud initiation and development. Flower bud initiation is completed within 3 to 21 days after the completion of a cold treatment (Pergola and Roh 1987). Immediately after cold storage, temperatures higher than 21°C should be avoided to prevent bud abortion and blast (Roh et al. 1986b). The optimum bulb cold treatment varies according to the cultivar. Other research involves development of cultural technologies to produce commercially acceptable flowering plants within 10 months starting from small bulblets or bulbils weighing less than 500 mg.

LIST OF NEW CROPS FOR EVALUATION

The following taxa or new hybrids are under evaluation or collected for propagation and test as pot plants, cut flowers and bedding plants.

Pot Plants

Abutilon hybrids (Malvaceae, Flowering maple)
Astilbe hybrids (Saxifragaceae)
Clematis hybrids (Ranunculaceae, Clematis)
Erica spp. (Ericaceae, Heath)
Exacum macranthum hybrid (Gentianaceae, Perisian violet)
Leptospermum spp. (Myrtaceae)
Passiflora hybrids (Passifloraceae, Passion flower)
Sinningia cardinalis (Gesneriaceae)
Vallota speciosa (Amaryllidaceae, Scarborough lily)

Cut Flowers

Eucrosia bicolor Ker Gawler (Amaryllidaceae)

Bedding Plants

Cuphea hybrids (Lythraceae, Cuphea)
Gentiana hybrids (Gentianaceae)
Pentas lanceolata Benth. (Rubiaceae)
Zauschneria californica Presl. (Onagraceae, California fuschia)

CONCLUSION

New crops research is dynamic and the interest in new crops is rapidly expanding among scientists, growers, and the general public. Each of the steps described in this article from the identification of new plant material with potential commercial value to its release with cultural information is important for the successful introduction of a new plant.

The program at the United States Department of Agriculture is a joint venture between the floral industry and the government. Systematic evaluation procedures with university and industry sponsors are designed to produce complete cultural information that can be utilized nationwide. This research program is an example of how government and industry can work together and how production technology can be developed with close communication and cooperation among individuals representing various geographical areas and interests.

REFERENCES

*We acknowledge the Society of American Florists, the American Floral Endowment, the Fred C. Gloeckner Foundation and New Crops Advisory Committee, for their financial support, Dr. R.G. Anderson, University of Kentucky, Dr. J. Frett, University of Delaware, Dr. T. Ferriss, University of Wisconsin-River Falls, Dr. G. Hanniford, Ohio State University, Dr. Brent Harbaugh, Gulf Coast Research and Education Center, Dr. R. Larson, North Carolina State University, Dr. W. Healy, University of Maryland, Dr. R. Regan and Dr. V. Walter, California Polytechnic State University, Dr. R.E. Widmer, University of Minnesota, and Dr. G.J. Wulster, Rutgers University for cooperative evaluation.

Fig. 1. Overall scheme of the new crops evaluation system.
Last update September 4, 1997 by aw