Correlations of oil and protein with isoflavone concentration in soybean [Glycine max (L.) Merr.].

Twelve isoflavones were detected by high-performance liquid chromatography in seeds of 17 soybean [Glycine max (L.) Merrill] cultivars grown at three locations. 6' '-O-Malonyldaidzin and 6' '-O-malonylgenistin together constituted 71-81% of total isoflavones, which ranged in concentration from 2038 to 9514 microg/g and averaged 5644 microg/g across locations and cultivars. The total as well as several individual isoflavones had a moderate negative correlation with oil across locations and cultivars. Six cultivars had a moderate or strong negative correlation of total isoflavones with oil. Five cultivars had a moderate or strong positive correlation of total isoflavones with protein. These results suggest that judicious selection of germplasm for soybean breeding may facilitate development of soybean lines with desirable isoflavone concentrations.