QTL mapping and mining of candidate genes for seed length in soybean

Soybean seed length (SL) is a key agronomic trait affecting both seed yield and appearance quality and is controlled by a complex interplay of multiple genes and environmental factors. Therefore, identifying major loci or genes associated with SL is critical for soybean molecular breeding. Phenotypic measurements of SL were conducted across three environments using a four‑way recombinant inbred line (FW‑RIL) population of 144 lines, along with their parental accessions.Linkage analysis identified 26 quantitative trait loci (QTLs) for SL. Candidate genes were predicted within the qSL-5-6 interval, which was consistently detected across multiple environments and analytical methods. Functional annotation, sequence variation, and haplotype analyses identified the tightly linked genes Glyma.05G238900 and Glyma.05G239100 as promising candidates for soybean SL that require further functional validation.

The online version contains supplementary material available at 10.1007/s11032-026-01697-y.