Unravelling the Genetic Architecture of Flowering in Common Vetch (Vicia sativa L.) Through Multi-Season QTL Mapping

Flowering time is a key adaptive trait in common vetch (Vicia sativa L.), influencing crop adaptation, yield potential, and forage quality. Despite its importance, the genetic basis of flowering in this species remains poorly understood. In this study, we analyzed the genetic architecture of flowering-related traits in an F_2:3 population under field conditions over two consecutive growing seasons. Four traits were evaluated using thermal time expressed as growing degree days (GDDs), and quantitative trait loci (QTL) analysis was conducted using a high-density genetic map derived from DArTSeq markers. The linkage map comprised 419 unique positions across six linkage groups, spanning 1728.5 cM. Ten QTLs associated with flowering traits were identified on chromosomes 2, 3, 4, and 6. Five QTLs were consistent across seasons, defining three major genomic regions controlling flowering. Additional season-specific QTLs suggested environmental effects on flowering responses. In silico analysis identified three candidate genes (VsFTc, VsFTa, and VsLFY) within flanking markers for stable QTL. This is the first report of QTLs for flowering in common vetch and provides targets for marker-assisted breeding to improve adaptation and resilience.