Construction of a molecular marker linkage map and its use for quantitative trait locus (QTLs) underlying drought tolerance at germination stage in soybean
A backcross inbred line (BIL) population of soybean was examined under polyethylene glycol (PEG) and well-watered conditions to identify the quantitative trait locus (QTL) controlling the drought-tolerance at germination stage. The recipient, SNWS0048, was a wild soybean with strong drought tolerance and the donor, Jinda73, was a drought-sensitive variety with superior agronomic traits. The molecular genetic linkage map was produced using the technique of simple sequence repeats (SSR) marker and tool of gene mapping, and 120 SSR markers and 2 morphology markers covering 1655.4 cM were produced. The average genetic distance between markers was 17.68 cM. The range of markers per linkage group was from 2 to 9, and the length was from 2.8 to 230.0 cM. Most of the markers among linkages were well distributed. 17 QTLs with additive effects and/or additive × environment interaction effects, involved in drought tolerance of soybean in germination stage, were found on linkage group G2-A2, G10-D2, G11-E. Out of these QTLs, 9 QTLs only were significant in additive effects, 8 QTLs had additive effect and additive effect by PEG treatment. Four tightly linked QTLs (Sat_199-I on MLG G2-A2, I-Satt327 on G2-A2, Satt528-Sat_365 on MLG G10-D2, Satt573-Satt606 on MLG G11-E) controlling drought tolerant traits in germination stage were revealed, and would be useful in future for marker assisted selection programs (MAS) and cultivar improvement.
Key words: Soybean, molecular marker linkage map, quantitative trait loci (QTLs), drought tolerance, germination stage.