Evaluations and Selections for High Isoflavone Black Soybean Mutants Induced by NaN3 Treatment

Sodium azide (NaN3) (2 mM) was used to induce mutation in black soybean variety CRWD for improvement of isoflavone content. The individual selections were made in M6, M7 and M8 generations, respectively. Both high levels of isoflavones and medium seed size traits were used as selection criteria. Across three growth seasons, the selected five NaN3-induced mutants accumulated more total isoflavones (average increases of 5% to 25%) than their wild type variety CRWD. Four mutants yielded more (average increases of 17% to 25%) than CRWD. Both mutants SA-M-03 (yellow cotyledon) and SA-M-05 (green cotyledon) are rich in isoflavones and may be useful in food and other applications.