Seed storability is especially important in the tropics due to high temperature and relative humidity of storage environment that cause rapid deterioration of seeds in storage. The objective of this study was to use SSR markers to identify genomic regions associated with quantitative trait loci (QTLs) controlling seed storability based on relative germination rate in the F2:3 population derived from a cross between vegetable soybean line (MJ0004-6) with poor longevity and landrace cultivar from Myanmar (R18500) with good longevity. The F2:4 seeds harvested in 2011 and 2012 were used to investigate seed storability. The F2 population was genotyped with 148 markers and the genetic map consisted of 128 SSR loci which converged into 38 linkage groups covering 1664.3 cM of soybean genome. Single marker analysis revealed that 13 markers from six linkage groups (C1, D2, E, F, J and L) were associated with seed storability. Composite interval mapping identified a total of three QTLs on linkage groups C1, F and L with phenotypic variance explained ranging from 8.79 to 13.43%. The R18500 alleles increased seed storability at all of the detected QTLs. No common QTLs were found for storability of seeds harvested in 2011 and 2012. This study agreed with previous reports in other crops that genotype by environment interaction plays an important role in expression of seed storability.

Development of soybean cultivars with high seed yield is a major focus in soybean breeding programs. This study was conducted to identify genetic loci associated with seed yield-related traits in soybean and also to clarify consistency of the detected QTLs with QTLs found by previous researchers. A population of 135 F2:3 lines was developed from a cross between a vegetable soybean line (MJ0004-6) and a landrace cultivar from Myanmar (R18500). They were evaluated in the experimental field of Kasetsart University, Kamphaeng Saen, Nakhon Pathom, Thailand in a randomized complete block design with two replications each in 2011 and 2012 growing seasons. The two parents exhibited contrasting characteristics for most of the traits that were mapped. Analysis of variance showed that the main effects of genotype and environment (year) were significant for all studied traits. Genotype by environment interaction was also highly significant for all the traits. The population was genotyped by 149 polymorphic SSR markers and the genetic map consisted of 129 SSR loci which converged into 38 linkage groups covering 1156 cM of soybean genome. There were 10 QTLs significantly associated with seed yield-related traits across two seasons with single QTLs explaining between 5.0% to 21.9% of the phenotypic variation. Three of these QTLs were detected in both years for days to flowering, days to maturity and 100 seed weight. Most of the detected QTLs in our research were consistent with earlier QTLs reported by previous researchers. However, four novel QTLs including SF1, SF2 and SF3 on linkage groups L and N for seed filling period and PN1 on linkage group D1b for pod number were identified in the present study.