Molecular mapping of a male-sterile gene in soybean

A newly identified genic male-sterile mutant in soybean [Glycine mar (L.) M err.] has high seed set under natural field conditions and is potentially u seful in breeding programs. Meiosis is normal in the mutant line. Sterility in this mutant is caused by failure of callose dissolution at the tetrad s tage, which results in microspore abortion; however, little is known about the male-sterile gene at the molecular level. The objective of this study w as to identify molecular markers linked with the male-sterile gene (ms) and to place the ms gene onto the soybean molecular genetic map. An F2 populat ion of 107 individuals was constructed from a cross between the mutant msMO S (ms ms) and the cultivar Minsoy (Ms Ms). Two hundred seventy markers, inc luding 219 RFLP and 51 SSRs, were evaluated. Of these, 102 RFLP probes and 31 SSR markers detected polymorphisms between the parents. The F2 populatio n was screened for segregation of these polymorphic molecular markers. Anal yses revealed that the male-sterile focus, designated 'ms', was located on linkage group Dib of the USDA/ISU soybean molecular genetic map. The availa bility of linked DNA markers will facilitate the genetic analysis of this m ale-sterility gene in relation to soybean breeding programs, and will be a starting point for the isolation of the ms gene by map-based cloning.