Genome-Wide Mapping Reveals Major and Stable Quantitative Trait Loci for Seed Oil Content in Soybean
Seed oil content is one of the primary breeding objectives in soybean. However, the genetic basis of seed oil content remains largely unexplored. In this study, we employed a recombinant inbred line (RIL) population consisting of 201 lines derived from a cross between Feidong and Guanyun, to identify quantitative trait loci (QTLs) for seed oil content in soybean under five environments. High broad-sense heritability (92.34%) indicates a substantial genetic contribution to phenotypic variation in this population and set of environments. A high-density genetic map containing 11,220 SNP markers was constructed, spanning 2507.62 cM, with an average distance of 0.22 cM between markers. By jointly using five QTL mapping methods, a total of 24 QTLs for seed oil content were identified, including eight stable QTLs detected in at least three environments and seven QTLs identified by all five methods. Out of these QTLs, qOil-5-4, qOil-9-2 and qOil-10-3 were considered as the major and stable QTLs. Within these three major and stable QTL intervals, except that Glyma.05g244100 (GmMFT/GmST05) is an experimentally validated gene, the other six genes that were highly expressed during seed development stages were identified as putative candidate genes requiring further validation. In conclusion, the major stable QTLs and candidate genes identified in this study facilitate the dissection of the genetic architecture underlying seed oil content and hold great potential for application in developing new high-oil soybean cultivars after further fine mapping and validation in independent genetic backgrounds.