Molecular mapping of male-sterile, female-fertile soybean ms2, ms3, and ms9 loci [Glycine max (L.) Merrill]
Soybean [Glycine max (L.) Merrill] is an obligate self-pollinated species (Burton and Carter, 1983). An efficient male-sterile system for hybrid seed production in soybean would involve finding close linkage between molecular and/or phenotypic markers and male sterility gene locus to facilitate early identification of the male-sterile genes in breeding programs. Then male-sterile, female-fertile plants could be readily distinguished from normal plants in segregating populations (Cregan and Quigley, 1997). Simple sequence repeats (SSRs) or microsatellites, can improve the efficiency of conventional plant breeding by carrying out selection not directly on the trait of interest but on molecular markers linked to the trait without being regulated by the environment (Mohan et al, 1997). The ms2, ms3, and ms9 nuclear gene mutations are inherited as monogenic recessive traits. Male sterile lines used in the research had displayed very low [ms2(A00-63)], and very high seed set [ms2(A00-39), ms3, and ms9], on the basis of previous evaluations (Ortiz-Perez et al., 2004). Minsoy (MsMs), which has high levels of molecular polymorphism compared to the male-sterile lines, was used as female or male parent. The main objective of the research was to molecularly map male-sterile, female-fertile genes ms3 and ms9, to determine their chromosome locations, and to verify the previously reported ms2 gene chromosome location. The ms3 locus was located between the markers on MLG Dlb, and in the same chromosomal region as Fspl, and msMOS loci previously mapped. The ms2 locus was confirmed to be located on MLG O. The ms9 locus was located on MLG N.