| Understanding the range and distribution of genetic diversity of a species is a critical component in the efficient management and utilization of germplasm. In this research, three sets of lines were surveyed with RAPDs in a study of soybean diversity. In the first set, 120 soybean accessions were selected from several regions in China, Japan, and S. Korea. Genetic diversity among accessions from China was larger than that within either Japan or S. Korea. Cluster analysis was effective in separating the accessions from China from those of Japan and S. Korea, but could not separate the accessions from Japan and S. Korea. Eighty Glycine soja and Glycine max accessions were selected from four Chinese provinces. The genetic distances within the G. soja accessions was much larger than that within the G. max accessions. Cluster analysis totally separated the two species and the clusters formed generally represented the geographical origin of the cluster members. RAPD fragments were also used to estimate the relationships among 18 U.S. and 32 Chinese major soybean ancestral lines. Cluster analyses generally separated the ancestral gene pools of the U.S. and China. Within countries, clusters reflected the geographical origin of the lines. The largest genetic distance was found between the ancestors of northern U.S. cultivars and the Chinese ancestral lines of central and southern China.; Using the soybean cultivar Williams, three near-isogenic lines of Williams with soybean mosaic virus (SMV) resistance, and F2 populations from crosses among them; a 1000 bp fragment designated OPN-111000 was found approximately 2 cM from Rsv1, a gene for resistance to SMV. Using this marker, homozygous and heterozygous SMV resistant plants could be easily distinguished based on fragment intensity.; To determine the efficacy of the pollen tube pathway transformation procedure plasmids carrying the bar and gus genes were applied to cut stigmas. Approximately 5000 seeds were produced from treated flowers. No plants derived from seeds produced by flowers treated with the plasmid carrying the bar gene were found to be as herbicide resistant as the positive control. Approximately 2% of seeds treated with the gus gene had a positive GUS reaction but primers specific for the gus gene failed to detect the gene. |
