GENE POOL SPECIFICITY, PAUCITY OF ENZYME VARIATION, AND PHASEOLIN POLYMORPHISM IN THE COMMON BEAN

The future of molecular markers in common bean (Phaseolus vulgaris L.) breeding and genetics lies in the discovery of more useful markers th an now available. One-dimensional SDS/PAGE analysis revealed four phas eolin types, ''S,'' ''T,'' ''C,'' and ''H,'' in proportions of 23.5%, 49.2%, 24.8%, and 2.5%, respectively. Molecular heterogeneity of phase olin subunits was not apparent. On the basis of the phaseolin types an d seed size, approximate to 75% of the landraces from Malawi probably were introduced from the Andean primary center of common bean domestic ation. The remaining 25% were small-seeded and probably originated fro m the Meso-American center of domestication of common bean. In Malawi, some amount of hybridization has occurred between genotypes from the two centers of domestication.