Variation of seed oil composition in parent and S1 generations of Lesquerella fendleri (Brassicaceae)

The seed oil of Lesquerella fendleri is valued for its use in industrial products including lubricants, methyl esters for diesel fuel additives, greases, drying agents, plastics, nylon-11, surfactants and protective coatings. The predominate fatty acids in the seed oil of all Lesquerella species are hydroxy fatty acids (HFA) and the HFA found in L. fendleri, the species being developed as a new crop for the southwestern U.S., is lesquerolic acid. The amount of variability for this and other fatty acids in its seed oil profile was considered somewhat narrow, limiting the potential progress in breeding for oil quality traits. A half seed method (HSM) of fatty acid analysis adapted for this small-seeded species, where the mean seed weight is 0.006 g, when compared to a bulk seed method (BSM) shows that much diversity actually exists. This variability was masked because the BSM is an average value of up to 50 seeds for each analysis compared to a half of a seed that results from a single pollination event. One thousand HSM seeds from an improved breeding population, WCL-LO3 were analyzed and the same breeding population analyzed by the BSM. A population of 32 unimproved accessions was also included for comparison because it represents the most diverse germplasm available for L. fendleri, originating from several geographical locations. Greater variability was detected with the HSM, especially for lesquerolic acid. Plants with lesquerolic acid values up to 74% and as low as 36% were found by the HSM, compared to an average of 55% by the BSM. These are the highest values reported for lesquerolic acid in this species. Lower values for two acids causing high oxidative instability of the oil, linoleic and linolenic were also detected. Plants with high and low lesquerolic acid values were then selected and S1 populations produced. The means from these 'high' and 'low' selected progeny populations were not the same as the respective mean parental values. The variability in these progeny was similar to the range and mean observed in the original population. This is likely due to at least a couple of genes segregating for this trait, requiring further generations for improvement and to determine the genetic inheritance of fatty acid.