Polymorphic differentiation and genetic variation of soybean by RFLP analysis

Twenty soybean accessions, representing local varieties, improved cultivars, plant introductions, breeding lines, two pairs of isogenic lines with different seed coat colors, and one Glycine soja accession were used for detecting genetic differentiation by restriction fragment length polymorphism (RFLP) markers. Seventeen probes which are believed to be primarily single copy sequences derived from a soybean genomic library of PstI digests were used. Eleven of these seventeen probes were proved to yield polymorphisms in one- or two-enzyme digestion. From a total of fifty-three probe -enzyme combinations, fifteen demonstrated polymorphism among accessions. DNA digested with HindIII showed a higher percentage of polymorphisms. The number of polymorphic alleles estimated from this study was forty-three alleles over twenty-five loci. Among these, 20% of loci have G. soja specific differences. Both dominant and codominant loci were noted, with 36% and 64% respectively. Alleles occurring in one or two accessions are considered rare. Fifty-six percent of polymorphic loci predominantly had rare allele, and only 44% of loci were informative. Variations within accessions were also noted with some probe-enzyme combinations. An average of 0.236 heterozygosity per locus was obtained from these RFLP marker loci. Dendrograms based on the coefficient of genetic similarity derived from this RFLP data classified the twenty accessions into five groups. Genetic differentiation could be achieved in eighteen of twenty soybean accessions by eleven probe-enzyme combinations. However, difficulty in distinguishing one pair of isogenic lines remained