Genetic and Biochemical Bases of Tocopherol Accumulation In Soybean (Glycine max [L.] Merr) Seeds.

Soybean (Glycine max L. Merril) is the largest protein and oilseed crop grown in the world and the principal source of Vitamin E (tocopherols) as a supplement. Tocopheols (α-, β-, γ- and δ-tocopherol) are powerful antioxidants responsible for a number of human health benefits, which include a reduced risk of lung cancer, osteoporosis and heart disease. The objectives of this study include 1) investigating environmental influences on tocopherol levels 2)  find simple sequence repeat (SSR) markers for selecting favourable lines 3) search the genebank through molecular mapping and use the candidate gene approach to determine which genes play a significant role in tocopherol accumulation. In the summer of 2009 and 2010, 79 recombinant inbred lines (RILs), parents and 10 checks were grown in field trials in Elora, Woodstock and St.Pauls, Ontario. Tocopherols were quantified through high performance liquid chromatography (HPLC).  Significant differences in the α-, γ-, δ-, and total tocopherol concentrations were found among the RILs and between the two parents, OAC Bayfield and OAC Shire, in 2009 and 2010. The wide range in values for α-, γ-, δ-, and total tocopherols among the RIL population indicated transgressive segregation for the traits. Out of 400 SSR markers that were used to screen the parents 104 showed polymorphism and were used to screen the entire RIL population. Currently, the RIL population is being subjected to molecular mapping and the candidate gene approach facilitates identification of the QTL and genes that have a significant influence on tocopherol accumulation. Plant breeders may use the genetic information generated in this study to develop improved tocopherol soybean varieties for the nutraceuticals industry and enhance soybean’s standing as a functional food responsible for decreased risk of health related problems in humans.