Endosperm Size Diversity in Domesticated, Wild, and Semiwild Soybean

ABSTRACT Past literature documents that domesticated soybean, Glycine max (L.) Merr., has trivial to almost nonexistent galactomannan‐containing endosperm in mature dormant seeds. Current preliminary observations confirm limited endosperm for many domesticated soybean accessions, but show that many others have markedly larger endosperm, as do all wild ( G. soja Sieb. & Zucc.) and semiwild ( G. gracilis Skvortz.) accessions. A trend toward small endosperm seems to have taken place during soybean domestication, which may be explained by some undesirable effects of galactomannans on monogastric animals. The broad diversity of genetic resources for endosperm size and associated galactomannans in available domesticated, wild, and semiwild accessions suggests use of soybean as a model plant for exploring differences, including water relations, between endospermic and nonendospermic legume seeds. It also suggests their use for breeding domesticated soybean with even smaller amounts of galactomannans for use in animal feeds, large amounts of galactomannans for commercial use, or genetic manipulation of the endosperm for other uses.