Quantitative trait locus analysis of flowering time in soybean using a RFLP linkage map

Flowering time is one of the most important traits in soybean breeding. To analyze the quantitative trait loci (QTLs) related to flowering time in soybean, we constructed a soybean linkage map using an F-2 population derived from a cross between two varieties, Misuzudaizu and Moshidou Gong 503, This linkage map consists of 247 RFLP loci, including 92 markers designed in this study using soybean green leaf-derived cDNA clones together with 4 phenotypic loci, covering a total of 33 linkage groups. Based on the number of days from sowing to first flowering of each Fz plant, we identified three QTLs, FT1, FT2 and FT3, for flowering time, The Moshidou Gong 503 alleles of FT1 and FT3, and the Misuzudaizu FT2 allele reduced the flowering time, These QTLs were remarkably effective and accounted for approximately 88% of the total phenotypic variation in this population, based on the multiple-QTL model. The most effective QTL, FT1, accounted for approximately 70% of the total variation and appeared to correspond to the E1, the locus for flowering time and maturity of the classical genetic map.