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The genus Lesquerella is a promising source of hydroxy fatty acid (HFA). Within this genus, Lesquerella fendleri is a good candidate for domestication in the and southwestern United States because it has high seed and oil yields, low seed dormancy, and low fruit dehiscence. Other species of Lesquerella, however, could be developed and expanded for other regions of the world with different climatic and environmental conditions. The objective of this study was to test the yield and oil content of several Lesquerella species in the Chubut River Valley, Patagonia, Argentina. The area is characterized by low temperatures during winter and high temperatures and radiation during summer. Two experiments were conducted for two consecutive years. Seed yield and oil content were determined for seven species of Lesquerella. In the first year, both fall and spring sowings were measured for all tested species. During the second year, Lesquerella angustifolia performance was evaluated together with three different accessions of L. fendleri. Spring sowings reduced seed and oil yield about 80% in L. fendleri and L gordonii (average of the two species, P < 0.05) compared with the fall sowings. These results were presumably caused by the longer daylength period during the summer at these latitudes compared with other sites. Yield was higher in L. angustifolia than other species and three times higher than L. fendleri, which was sown at the same time. The higher yield obtained with L. angustifolia was the result of the combination of both high seed weight and seed number per plant. When L. angustifolia was compared with L. fendleri germplasm. originated from and environments and with two accessions of the same species collected from high elevations, the better performance of the former was confirmed. These results clearly demonstrate that L. angustifolia performs better than L fendleri in the irrigated valleys of Patagonia, and also that L fendleri yields would be low under environments with very cold winters and high latitudes. Thus, fall plantings of L angustifolia could be considered as an alternative source of HFA at this site and other similar high-latitude environments. (C) 2003 Elsevier Science B.V. All rights reserved.