Abstract Total spikelet number per spike (TSS) is one of the key components of grain yield in wheat. Chromosome (chr.) 2D contains numerous genes that control TSS. In this study, we evaluated 138 F8 recombinant inbred lines (RILs) derived from an F2 population of a synthetic hexaploid wheat line (SHW-L1) and a common wheat cultivar (Chuanmai 32) for TSS in six different environments. To identify quantitative trait loci (QTL) for TSS, we constructed an integrated high-density genetic map of chr. 2D containing two simple sequence repeats, 35 diversity array technology markers, and 143 single nucleotide polymorphisms. We identified three stable QTL for TSS that individually explained 9.7–19.2% of the phenotypic variation and predicted 23 putative candidate genes within the QTL mapping interval. Overall, our results provide insight into the genetic basis of TSS in synthetic hexaploid wheat that may be useful in breeding high-yielding wheat cultivars.

Abstract Pre-harvest sprouting (PHS) is a major abiotic factor affecting grain weight and quality, and is caused by an early break in seed dormancy. Association mapping (AM) is used to detect correlations between phenotypes and genotypes based on linkage disequilibrium (LD) in wheat breeding programs. We evaluated seed dormancy in 80 Chinese wheat founder parents in five environments and performed a genome-wide association study using 6,057 markers, including 93 simple sequence repeat (SSR), 1,472 diversity array technology (DArT), and 4,492 single nucleotide polymorphism (SNP) markers. The general linear model (GLM) and the mixed linear model (MLM) were used in this study, and two significant markers (tPt-7980 and wPt-6457) were identified. Both markers were located on Chromosome 1B, with wPt-6457 having been identified in a previously reported chromosomal position. The significantly associated loci contain essential information for cloning genes related to resistance to PHS and can be used in wheat breeding programs.