Identification of a major stable QTL for spikelet number in wheat ( Triticum aestivum L.) and its genetic effects analysis on yield-related traits

As one of the important spike components, spikelet number is closely related to wheat yield. In the present study, a major stable QTL for spikelet number per spike (SNPS), qSnps-7D , was identified using a recombinant inbred line mapping population derived from the cross between Kenong 9204 (KN9204) and Jing 411 (J411) (KJ-RILs). To decipher its genetic effects on yield-related traits and selection effects in wheat breeding process, phenotype data together with genotype data from KJ-RILs and a natural mapping population were collected. qSnps-7D was mapped to the interval of 1.63 Mb on chromosome 7D in the KN9204 genome assembly in 4 of the 6 datasets. The favored alleles from KN9204 could significantly increase SNPS, kernel number per spike (KNPS). The diagnostic markers for SNPS were further developed and validated. The selection utilization rate of the favored haplotype in foreign varieties was lower than that in China, and it showed an increasing trend with time passage, with the ratio reaching more than 50% since the 1990s. In addition, loci for yield-related traits co-located with qSnps-7D were sorted out. Meanwhile, the relationship between SNPS and its components as well as other important yield-related traits were also discussed. Taken together, the studies will lay foundation for gene cloning and molecular breeding utilization of qSnps-7D .