Genome-Wide Association Study for Yield and Yield-Related Traits in Chinese Spring Wheat

Abstract

Wheat (Triticum aestivum L.) is one of the important grain crops that fulfill global food security requirements. Understanding the genetic basis of wheat yield and related traits is crucial for increasing yield through marker-assisted selection (MAS). In this study, a phenotypic analysis was conducted on the yield and related traits of 192 Chinese spring wheat genotypes in six field environments. Based on the 90K wheat SNP iSelect assay, a genome-wide association study (GWAS) identified 84 stable and significantly associated signals at 50 loci for 8 out of the 10 analyzed traits. These traits included grain yield (1), plant height (6), spike length (21), productive spikelet rate (12), kernel number per spikelet (1), kernel number per main spike (2), thousand kernel weight (5), and test weight (2). Seventy-one stable SNP markers were mapped to annotated genes, with 51 of them located in the coding sequences (CDSs) of 47 explanatory genes. Haplotype analysis revealed three blocks on chromosome 5A and two blocks on chromosome 5D associated with plant height (PH). Varieties with different haplotypes at these loci displayed a significant difference in plant height. The performance of traits was improved by increasing the number of superior alleles for productive spikelet rate and spike length. These results provided prospective alleles for controlling yield and yield composition in wheat breeding. These alleles could be used for marker-assisted selection to improve wheat yield.