Isozyme diversity in seven amaranth species

Eight commercial varieties and 35 experimental strains, obtained from the a maranth breeding program developed in our institution, belonging to seven A maranthus spp,: A. caudatus L., A. cruentus L., A. hypochondriacus L. Rob., A. hybridus L.,A. mantegazzianus Pass., A. dubius Mart. ex Thell. and A. t ricolor L. were examined for genetic variability using isozymes markers. Se ven enzyme systems involving 23 polymorphic bands determined 38 electrophor etic patterns In seed extracts. Phenotype frequencies of these patterns wer e evaluated by their shannon-Weaver diversity indices. The latter were subj ected to two analyses of finance: among enzymes and among species. The form er revealed that in all seven enzyme systems genetic variability was simila r; the latter showed that thee seven species differed in their genetic dive rsity [diversity indices]: A, hypochondriacus, A. mantegazzianus and A. cru entus were most diverse; A. caudatus and A. tricolor were Intermediate and A, hybridus and A. dubius were least diverse. The apportionment of the inde x showed 60% of variation to be interspecific and 40% intraspecific. This i ndicates that selfing species can maintain diversities similar to those of outcrossing species. The results suggest that isoenzymatic seed characteris tics can be a valuable complement of other morphological and biochemical ma rkers in amaranth breeding programs for the characterization of cultivars.