Submitted to: Biennial Conference on Molecular and Cellular Biology of the Soybean
Publication Type: Abstract Only
Publication Acceptance Date: 8/29/1996
Publication Date: N/A
Technical Abstract: A major gene for soybean cyst nematode (SCN) resistance is located near the top of linkage group "G" of soybean. This gene is significant against multiple nematode races in PI 209332, PI 88788, PI 90763, and Peking, and has also been uncovered in PI 437654. In previous experiments, marker-based selection with RFLP markers at the F2 generation was more than 90% accurate in identifying resistant lines at the F5:6 generation. Nonetheless, RFLP markers are difficult to use and their usefulness is hampered in soybean by low levels of DNA sequence diversity. Because of these difficulties, we have searched for a simple sequence repeat (SSR) marker that would be easy to use, informative, and tightly linked to the major SCN locus. One SSR marker, BARC-Satt038 (subsequently referred to as Satt038), is located approximately 2.5 centimorgans away from the resistance gene. In preliminary studies, Satt038 exhibited a gene diversity value of 0.76 and was polymorphic between several resistant genotypes (PI 88788, PI 90763, and PI 209332) and two susceptible varieties (Evans and Sturdy). Surprisingly, Peking exhibited the same sized product as did the two susceptible varieties tested. In ongoing studies, we seek to evaluate Satt038 on a wider range of soybean genotypes, determine its map location with greater precision, and identify a second SSR marker on the opposite side of the SCN resistance gene.