GENEPOOL VARIATION IN GENUS GLYCINE SUBGENUS SOJA REVEALED BY POLYMORPHIC NUCLEAR AND CHLOROPLAST MICROSATELLITES

A combination of nuclear and chloroplast simple sequence repeats (SSRs ) have been used to investigate the levels and pattern of variability detected in Glycine max and G. soja genotypes. Based on the analysis o f 700 soybean genotypes with 115 restriction fragment length polymorph ism (RFLP) probes, 12 accessions were identified that represent 92% of the allelic variability detected in this genepool. These 12 core geno types together with a sample of G. max and G. soja accessions were eva luated with 11 nuclear SSRs that detected 129 alleles. Compared with t he other G. max and G. soja genotypes sampled, the core genotypes repr esent 40% of the allelic variability detected with SSRs. Despite the m ulti-allelic nature of soybean SSRs, dendrograms representing phenetic relationships between accessions clustered according to their subspec ies origin. In addition to biparentally inherited nuclear SSRs, two un iparentally (maternally) transmitted chloroplast SSRs were also studie d. A total of seven haplotypes were identified, and diversity indices of 0.405 +/- 0.088 and 0.159 +/- 0.071 were obtained for the two chlor oplast SSRs. The availability of polymorphic SSR loci in the chloropla st genome provides new opportunities to investigate cytonuclear intera ctions in plants.