His research focus is on physiological, environmental and genetic interactions that affect the production of seed and seedling growth of soybean (Glycine max). Strategies used emphasize modeling the growth of wild soybean (Glycine soja), ancestral and modern cutlivars, and experimental lines modified for altered seed composition. He is also an international authority on the genetics and breeding of birdsfoot trefoil (Lotus corniculatus) and introduced and native Lotus species.