Isozyme diversity in reiation to domestication of gaur (Cyamopsis tetragonoloba (L.) Taub.)

A survey of isozyme systems in a relatively little known legume, the guar (clusterbean), Cyamopsis tetragonoloba 1.) Taub., has been reported for the first time. The plant material included seven landrace accessions from India, six released cultivars from the United States, and two wild species populations of C. senegalensis and C. serrata. Starch gel electrophoresis protocols for seven isozyme systems, viz., MDH, IDH, PGD, ADH, PGI, GOT and ME were largely developed. The combination of cotyledons as the plant tissue, and Tris-HCl with ascorbic acid, PVP, PWP and 2-mercaptoethanol as the extraction buffer provided the best resolution of isozymes. Out of the four gel-electrode buffer systems attempted, the Histidine system was selected to study the patterns of diversity. All the cultivated species accessions were uniformly monomorphic. Two isozyme phenotypes were recorded for ADH in C. senegalensis, and for GOT in C. serrata. A preliminary interpretation of the banding patterns in relation to domestication of guar has been made.