Submitted to: American Journal of Botany
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/2/2004
Publication Date: 1/15/2005
Citation: Salywon, A.M., Dierig, D.A., Rebman, J.P., Rodriguez, D.J., 2005. Evaluation of new lesquerella and physaria (brassicaceae)oilseed germplasm. American Journal of Botany. 92(1):53-62. Interpretive Summary: Species of Lesquerella and Physaria, in the mustard family, are being developed by our plant breeding program as new domestic industrial oilseed crops for their hydroxy fatty acids (HFAs). Although HFAs are considered a strategic material by the United States Government, the only commercial source of HFAs currently available in the U.S. is castor oil, all of which must be imported. Lesquerella fendleri has the greatest agronomic potential and could be grown in 1.4 million acres of suitable farmland in the southwestern U.S. All plant breeding programs manipulate and manage genetic variability by creating new genetic combinations to produce new cultivars and to sustain the viability of existing ones. Much genetic diversity is available in wild populations of Lesquerella and Physaria that can be transferred to existing breeding programs. Our goal was to collect, evaluate and make available new wild accessions of Lesquerella and Physaria germplasm from throughout the U.S. and Mexico. From 1995 to 2001 we collected and evaluated 113 accessions of 24 species of Lesquerella and 39 accessions of 13 species of Physaria. Our evaluations, suggest that several of these species have potential for agronomic use. In addition, the cultivars currently being developed by our program will benefit from the natural variation in oil quantity and quality traits from many of the new accessions. These collections will help enhance the yield and desirable attributes of the oil of our cultivars and will result in a more cost efficient and abundant source of the oil, opening up new opportunities for products and new markets, as well as reducing our dependence on foreign imports.
Technical Abstract: The seeds of species of Lesquerella and the closely related genus Physaria (Brassicaceae) contain hydroxy fatty acids (HFAs) as the main constituent of their seed oil. HFAs are used in the production of a variety of industrial products, cosmetics and pharmaceuticals. Currently the only commercial source of HFAs is castor oil, which is imported. Lesquerella fendleri (Gray) Wats. is being developed as a new crop for arid regions of the southwestern United States as an alternative source of HFAs. In order to meet desired objectives of improved oil yield and quality for our breeding program and in order to discover related species with potential for domestication, an effort was made to increase available germplasm from wild populations. From 1995 to 2001, 81 accessions from 28 species of Lesquerella were collected in the United States and 32 accessions from four species were collected in Mexico. In 1996 and 2001, 39 accessions from 13 species of Physaria were collected from the southwestern U.S. Seed weight and oil characteristics for 14 species of Lesquerella and 11 species of Physaria are reported here for the first time. Seed-weights ranged from 0.35 to 0.71 g/1000 seeds for L. fendleri compared to 4.4 to 5.8 g/1000 seeds for P. lepidota. Seed-oil content highs from single accessions were 30.5 % in L. fendleri, 32.2 % in L. rectipes and 35.4 % in P. acutifolia. The fatty acid profile of all species of Physaria and most of the lesquerolic acid-rich species of Lesquerella contained from 30-55 % lesquerolic acid, although several species contained more than 60 %. These collections of wild germplasm provide a diverse gene pool from which traits can benefit our breeding program to produce a domestic source of HFAs.