Characterization of Cytoplasmic Diversity in Soybeans by Restriction Endonuclease Analysis1

Abstract

The limited geographic origin and paucity of maternal ancestors is a reasonable basis for suspecting that cytoplasmic uniformity exists among currently grown soybean (Glycine max (L.) Merr.) cultivars. Restriction endonuclease fragment analysis of mitochrondrial DNA (mtDNA) was used to assess the cytoplasmic diversity in soybeans. Ten sources of soybean germplasm including the predominant maternal ancestors of cultivated soybeans and their putative wild progenitor, G. soja Sieb. and Zucc., were examined. MtDNA isolated from each test genotype was digested with the restriction endonucleases BamI or SalI and the resulting fragments separated by gel electrophoresis. Comparison of the restriction patterns showed a high degree of homology among the mtDNAs from the test genotypes. The restriction patterns of the maternal ancestors were indistinguishable, with the exception of a single unique band present in the Sal‐restriction pattern of the cultivar ‘Lincoln’. Other intraspecies differences of one or two bands were noted among the banding patterns of the test genotypes. The fragment pattern of G. soja was readily distinguishable from the maternal ancestors when digested by either enzyme. Results of this study tended to substantiate the premise that cytoplasmic uniformity exists among currently grown soybean cultivars.