The genetics of domestication of the azuki bean (Vigna angularis)

Genetic differences between azuki bean (Vigna angularis var. angularis) and its presumed wild ancestor (V. angularis var. nipponensis) were resolved into QTLs for traits associated with adaptation to their respective distinct habits. A genetic linkage map constructed using progenies from a cross between Japanese cultivated and wild azuki beans covers 92.8% of the standard azuki bean linkage map. A reciprocal translocation between cultivated and wild azuki bean parents was identified based on the linkage map having a pseudolinkage group and clustering of seed productivity related QTLs with large effect near the presumed break points. In total, 162 QTLs were identified for 46 domestication related traits. Domestication of azuki bean has involved a trade off between seed number and seed size. Fewer but longer pods and fewer but larger seeds on plants with shorter stature in cultivated azuki bean being at the expense of overall seed yield. Genes found related to germination and flowering time in cultivated azuki bean may confer a selective advantage to the hybrid derivatives under some ecological conditions and explain why azuki bean has evolved as a crop complex in Japan.

Key Words: QTL, Reciprocal translocation, Seed traits, crop complex, domestication syndrome

Online ISS 1091-6490
Copyright 2008 by the Genetics Society of America
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