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Mapping a recessive male sterility gene (ms2) in soybean
The most common breeding method used in soybean varietal development programs is to make many biparental matings, self the resultant progeny to near-homozygosity, and then evaluate the inbred progeny of each mating in performance trials to identify the few progeny that are worthy of selection and release as new cultivars. This could amount to an 8-season recurrent selection cycle, but because a breeder will generate biparental matings every season, there are, in any given season, eight different groups of biparental progeny moving through the cycle, with limited opportunity for genetic exchange amongst them. Is there an alternative to this method? Yes, a method called male-sterile-facilitated cyclic breeding (MSFCB) could be used in soybean cultivar development to provide greater recombinational opportunities. The ms2 allele for genetic male-sterility can be used to facilitate the annual biparental matings of elected elite germplasm lines (chosen each year) with male-sterile plants derived from a prior set of such matings. At present, seeds of a mixture of elite breeding selections are planted in rows of an intermating block, with 1600 F2 seeds (segregating 3MF:1MS) in the alternating rows. Approximately 400 of the segregating F2 plants are expected to be male-sterile, so the other 1200 must be rogued as soon as one flower opens on each plant and upon inspection, is recognized as being male-fertile. To make MSFCB more convenient, the F2 male-sterile genotypes could be identified prior to flowering by molecular markers flanking the Ms2 locus (located near the bottom of LG-O). A population of 513 F2 individuals segregating for male-sterility served as the mapping population. Markers for 1200 RAPDs, 1280 SRAPs, 64 AFLPs, 16 SSRs, 21 SNPs, and 32 markers derived from BAC-end and cDNA sequences near the bottom of LG-O were evaluated, first for parental polymorphism, and then via bulk segregate analysis (BSA). Bracketing markers were successfully identified. The SNP S01296, SSR Sat_190, SRAP SR1241, and CAPS 4770a_AciI markers were found to be linked to the proximal side of the Ms2 locus at distances of about 13.8 cM, 11.2 cM, 6.3 cM, and 4.3 cM, respectively. SNP markers S02269 and S04890 were found to be linked distal to the Ms2 locus at flanking distances of about 5.7 cM and 11.8 cM, respectively. Identification of these linked molecular markers provide a means of characterizing F2 seed or seedlings as to their Ms2Ms2, Ms2ms2, and ms2ms2 genotypes with respect to the MSFCB program.^
Agriculture, Agronomy|Biology, Genetics|Agriculture, Plant Culture
Chaky, Julian Marco, "Mapping a recessive male sterility gene (ms2) in soybean" (2006). ETD collection for University of Nebraska - Lincoln. AAI3236906.