GENOMIC REGIONS THAT UNDERLIE SOYBEAN SEED ISOFLAVONE CONTENT

¹ Dept. of Plants Soil and General Agriculture, Southern Illinois University at Carbondale, Room 176. Carbondale, IL 62901-4415

² Department of Animal Science, Food and Nutrition, Southern Illinois University at Carbondale, Carbondale, IL 62901-4415

Soy products contain isoflavones (i.e., namely genistein, daidzein and glycitein) that display biological effects when ingested by humans and animals, these effects are specie, dose and age dependent. Hence controlling the content and the profiles of phytoestrogens in soybeans is a key control for their biological effect. Our objective was to identify loci that underly isoflavone content of soybean seeds. The study involved 100 recombinant inbred lines (RIL) from Essex X Forrest (two soybean cultivars that contrast for disease resistance, water deficit tolerance, yields potentials and phytoestrogen content). Isoflavone content for each line was performed by HPLC as described by wang and Murphy 1994 using two sub-populations: 40 and 60 lines. Isoflavone content of soybean was compared against 150 polymorphic DNA markers. Six genomic region associated with isoflavones seed content were detected: Two on molecular linkage group N and one on each A1, B1, K and H. Marker assisted selection for seed phytoestrogens using linked DNA markers can be used to enhance and manipulate the profile of total genistein, daidzein and glycitein in soybeans seeds. Tightly linked markers can be used in map based cloning of genes associated with Isoflavone content.