Identification of candidate genes and favourable haplotypes for yield traits in rice based on a genome-wide association study

The key to food security is increasing rice yield. Therefore, we performed a genome-wide association study (GWAS) to analyse and identify the effects of plant height (PH), effective tiller number (ETN), heading date (HD) and grain weight per plant (GWPP) on rice yield using 1,220,522 single-nucleotide polymorphisms (SNPs) from 168 rice accessions. The PH, ETN, HD, and GWPP phenotypes of the 168 rice accessions were analysed in 2019, 2020 and 2021, and an abundance of phenotypic variation was found. One QTL for PH was detected on chromosome 4, one QTL for ETN on chromosome 11, two QTLs for GWPP on chromosome 2, and one QTL for HD on chromosome 5, all of which were detected in 3 years of the study period through a general linear model (GLM) and mixed linear model (MLM). We detected two QTLs related to the traits by using multi-trait GWAS. In addition, we identified four novel genes responsible for rice yield. Haplotype analysis indicated that LOC_Os02g07680 was highly associated with GWPP, LOC_Os11g18570 was highly associated with ETN, LOC_Os04g49210 was highly associated with HD, and LOC_Os05g34600 was highly associated with PH. The results provide important genetic information for PH, ETN, HD and GWPP studies, laying the foundation for increasing rice yield.