QSNS.sicau-D12-3B: A novel and major validated QTL governing wheat spikelet number with significant breeding...

Spikelet number per spike (SNS), a key determinant of grain yield in wheat, is a complex quantitative trait controlled by spike meristem activity. Unraveling its genetic basis is essential for wheat high-yield breeding. Here, we identified a stable quantitative trait locus (QTL), QSNS.sicau-D12-3B, governing SNS using a recombinant inbred line (RIL) population derived from a cross between the high-SNS line 03D501 and the low-SNS line 2011. This QTL was consistently detected across seven environments and mapped to a 5.814 Mb interval on chromosome 3B (flanked by markers K_sau_3B_619673521 and K_sau_3B_625487833). Conditional QTL analysis revealed that QSNS.sicau-D12-3B acts independently of plant height and spike length but may modulate SNS through its effect on spike density. Validation in diverse genetic backgrounds confirmed the robust association between QSNS.sicau-D12-3B and SNS, underscoring its potential for yield improvement. Our findings provide novel insights into the genetic architecture of SNS and offer a promising target for molecular breeding in wheat.