QTL analysis of spike traits and KASP marker validation for basal sterile spikelet number in wheat.

Spike traits play a pivotal role in determining wheat yield. In this study, two recombinant inbred line (RIL) populations were employed to identify quantitative trait loci (QTLs) for spike length (SL), spikelet number per spike (SNS), and basal sterile spikelet number (BSSN). A total of 30 QTLs were identified, including 7 major-effect QTLs that exhibited stability across multiple environments. Among these, two novel QTLs were discovered: QBssn.A-3 A.3 and QBssn.AV-5B.2. Furthermore, it was found that the combination of these two QTLs with other major effect QTLs had no impact on thousand-kernel weight (TKW). For QBssn.A-3 A.3, a Kompetitive Allele-Specific PCR (KASP) marker was developed and validated based on its physical location. Additionally, candidate genes within the intervals of QBssn.A-3 A.3 and QBssn.AV-5B.2 were predicted, based on these genes primarily associated with sterile spikelet number per spike. This study provides a foundation for future map-baesd cloning of genes related to spike traits, and for the breeding of high-yield wheat varieties.