The agronomic community is encouraging diversification by the growth and development of new crops. Once a plant has been identified as having the potential to become a new crop, it must be developed into a marketable commodity. Desirable traits may be transferred to the crop from germplasm available in accessions which are preserved at Plant Introduction stations.
The WRPIS currently utilizes two Washington state locations in the regeneration program. A third environ-ment at Maricopa, Arizona will soon be operating and will allow seed increase of accessions of Parthenium argentatum Gray (guayule), Simmondsia chinensis (Link) C. Schneider (jojoba), Lesquerella S. Watson, and other species which are adapted to the southwest desert climate.
The WRPIS germplasm collection is a plant materials resource for new crops, underexploited crops, herbs, medicinal, and ornamental plants. Samples of available accessions, usually 50 to 100 seeds, are sent upon request to researchers worldwide.
Lesquerella, Lamiaceae, is also known as bladderpod. Many of the species within this genus are native to the arid southwestern United States. Lesquerella is considered a prime candidate to be used as an oil seed crop because of the presence of three new hydroxy fatty acids which are similar to a primary component in castor oil. Castor oil is a main ingredient in the production of lubricants, plastics, and drying agents (Purseglove 1974). Lesquerella seed meals were found to be relatively high in lysine, indicating potential for use as a protein supplement in feed grains (Thompson and Dierig 1988). The 53 accessions maintained by the WRPIS will be increased at a new off-station site located at Maricopa, Arizona.
Lactuca sativa L., Asteraceae, or lettuce, is not normally considered a new crop. In recent years, the practice of offering only `iceberg' lettuce in American supermarkets has declined, and in most produce sections, one can now find selections of red, leaf, romaine, and other types of lettuce. Germplasm for developing new types of lettuce with potential consumer appeal is abundant in the 742 accessions managed by the WRPIS.
Lupinus L., Fabaceae, the "legume" family, have been a useful crop for both human consumption and livestock feed for centuries (Forrest 1991). Lupinus albus L. (white lupin), and L. mutabilis Sweet (pearl lupin or tarwi) have been the subject of several studies. In both species, lines with low levels of alkaloids have been found. These lines are desirable as food for livestock and humans due to the high protein, up to 50%, and oil content, up to 24% (Langer and Hill 1982). A wide assortment of germplasm is present in the 743 accessions of Lupinus which the WRPIS maintains and regenerates at the Soil Conservation Service Plant Materials Center at Pullman, Washington. Lupins vary in such phenotypic characters as growth habit, flower color, seed color, and height.
Parthenium argentatum Gray, Asteraceae, commonly called guayule, is a drought tolerant shrub that is a good source of natural rubber. It was cultivated in the southwestern United States during World War II when Hevea rubber was not available from Southeast Asia (Princen 1977). Although direct seeded stand establishment has been a factor limiting the development of guayule as a crop, researchers have recently developed techniques to alleviate this problem (Foster and Moore 1989). The 27 guayule accessions at the WRPIS will be regenerated at the Maricopa Research facility.
Lens culinaris Medikus, Fabaceae, also known as lentil, has been cultivated since ancient times in Egypt, southern Europe, and western Asia (Purseglove 1974). Lentils are highly branched annual legumes that grow to a height of about 40 cm. They are grown mostly in Pakistan and north India (Langer and Hill 1982). The WRPIS is located in the Palouse Region of Washington, where 98% of the lentils produced in the United States are grown. The American Dry Pea and Lentil Association estimated that in 1991, 76,000 t of lentils were grown on the Palouse. A national lentil festival is held in Pullman, Washington every September to promote lentils and lentil cuisine. The WRPIS lentil collection consists of 2251 accessions. Many accessions have been used extensively in lentil cultivar development programs.
Cicer arietinum L., Fabaceae, commonly referred to as chickpea or garbanzo bean, is an annual legume that is thought to have originated in western Asia. Chickpea seed has approximately 20% protein, 5% oil, and 60% carbohydrate. The whole or ground seed is used in many ways by Mediterranean cultures and is also a favorite ingredient in the American salad bar. Livestock are fed crop residues (Langer and Hill 1982). The 3,741 accessions of chickpea managed by the WRPIS are grown at the Pullman site. The WRPIS and the USDA Grain Legume Genetics and Physiology Research Project are collaborating on a project to screen for resistance to Ascochyta blight, a major disease of chickpea, to develop large-seeded, blight resistant cultivars. To date, 400 WRPIS accessions have been screened for resistance to blight.
The WRPIS is also responsible for the preservation of other new and interesting crops. Cucurbita foetidissima Kunth (buffalo gourd), Limnanthes R. Br. (meadowfoam), and Simmondsia chinensis (Link) C. Schneider (jojoba) as well as many herbs, ornamental, and medicinal plants (Table 1) are of potential interest to those working to introduce or improve new crops.
|Scientific name||Common name||Use|
|Achillea millefolium L.||Yarrow, milfoil||Ornamental, an ingredient in mead (Adams 1987)|
|Artemisia absinthium L.||Wormwood||Aromatic, ornamental (Adams 1987)|
|Borago officinalis L.||Borage||Culinary herb with cucumber flavor, source of gamma-linolenic acid (Fletcher 1972)|
|Papaver somniferum L.||Opium poppy||Source of codeine and morphine (Fletcher 1972)|
|Plantago ovata L.||Psyllium||Laxative, stabilizer in ice cream (Morton 1977)|
|Salvia officinalis L.||Sage||Culinary herb used as pork and poultry seasoning (Prakash 1990); source of antioxidants|
|Sanguisorba minor Scop.||Salad burnet||Culinary herb (Prakash 1990)|
|Satureja hortensis L.||Summer savory||Culinary herb (Adams 1987)|
|Trigonella foenum-graecum L.||Fenugreek||Culinary herb, sprouts for salad, imitation maple syrup from seed, used in salves and poultices (Adams 1987)|
Fig. 1. Germplasm maintenance program.