This study was aimed to determine the contents and the association of B vitamins from seeds of 10 black and one yellow soybean (Glycine max (L.) Merr.) varieties with either green or yellow cotyledon. Thiamine, flavin adenine dinucleotide (FAD), riboflavin and total riboflavin were found highest in
Symbiotically defective auxotrophic mutants were isolated by transposon Tn5 mutagenesis of Rhizobium fredii HH303, a fast-growing microsymbiont of North American commercial soybean cultivars such as Glycine max cv. Williams. Three different Tn5-carrying suicide vectors, pBLK1-2, pSUP1011, and pGS9,