Collection and evaluation of new Lesquerella and Physaria germplasm

Abstract

Lesquerella and the closely related genus Physaria are prime candidates as a new, alternative source of hydroxy fatty acids (HFA) for industrial uses. At present, castor oil is the only natural source of these HFA for commerce. To expand the germplasm base of these taxa for our breeding program and the National Germplasm System (NPGS), we collected species from a wide geographic region in the United States. Ih 1993, 44 accessions of Lesquerella fendleri, 38 accessions from nine other Lesquerella species, and three accessions' of two different Physaria species were obtained. In 1994, 41 additional accessions of L. fendleri and 51 accessions of ted other Lesquerella species were collected. A total of 20 different species of Lesquerella and two Physaria species were collected over the two years. Oil characteristics and seed size of eight of these Lesquerella and one Physaria species have not previously been reported. Twelve of these taxa have not been available in the NPGS. Populations of L. fendleri collected in Arizona had higher seed-weights than those collected from Texas and New Mexico. Some of the new accessions had seed-weights higher than germplasm presently in the USDA-ARS breeding program. Diverse growth habits were found in populations from all three states. We believe that other species of Lesquerella and Physaria could later be developed as a source of HFA in regions other than the arid southwestern United States. Accessions of Lesquerella douglasii had the same or higher seed-oil content than L. fendleri and also higher seed yields. Two accessions of Physaria newberryi had seed-weights that ranged between 4.5 and 6.2 g/1000 seeds compared to that of 0.25 to 1.1 g/1000 seeds for L. fendleri. Seed-oil contents of P. newberryi averaged 30.8% compared to 23.8% for L. fendleri. Preliminary seed increase and evaluation of oil content and composition were completed on 14 L. fendleri populations from the 1993 collection under field conditions in Phoenix, Arizona. Accessions were compared to the original populations collected in 1993 and 1994 for growth habit, seed size, and seed-oil content and quality.