Variability of Seed Oil Content and Fatty Acid Composition in the Entire USDA Sesame Germplasm Collection.

Sesame (Sesame indicum L.) is one of the oldest oilseed crops with a long history of cultivation for its edible seeds and oil. The U.S. sesame germplasm collection (containing about 1,232 accessions) is a useful genetic resource for improving seed quality and enhancing grain yield. Variability of seed oil content and fatty acid composition for the entire USDA collection were quantified from the stored seeds by NMR and GC. There was a significant variation in seed weight ranging from 0.09 to 0.50 g/100 seeds with an average of 0.32g. The average oil content was 54.9% ranging from 25.7 to 65.5%. The sesame seeds mainly contained four major fatty acids: 44.84% linoleic acid (C18:2), 39.46% oleic acid (C18:1), and 9.02% palmitic acid (C16:0), and 5.16% palmitoleic acid (C16:1). Significant variation was also detected in these four major fatty acids.  Based on the morphology observation and chemical analysis, at least two accessions were misnamed and need to be reclassified. The results obtained from this study may be useful for sesame improvement in breeding programs and further germplasm collection in curation and exchange programs.