RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISMS OF THE PHYTOHEMAGGLUTININ GENES IN PHASEOLUS AND VIGNA (LEGUMINOSAE)

Restriction fragment length polymorphisms at the phytohemagglutinin (PHA) locus were determined among 21 genotypes of Phaseolus vulgaris, P. coccineus, P. acutifolius, P. lunatus, and three Vigna species, using five restriction enzymes and one double digestion, in order to provide molecular evidence for their genetic relatedness. The dissimilarity between genotypes was estimated from binary RFLP data. The dissimilarity was high among species (from 0.75 to 0.95), and of variable extent among genotypes of the same species (0.33-0.89). In P. vulgaris, two different DNA hybridization patterns were found, giving further evidence for two major gene pools in that species. The restriction patterns of P. vulgaris var. aborigineus, the putative ancestral form of P. vulgaris, exhibit clear homology to P. vulgaris genotypes. An undefined landrace from Taiwan could be identified as a P. vulgaris genotype. RFLP-based trees for the phytohemagglutinin genes of the species studied were computed with several distance matrix and parsimony methods.