Large‐scale GWAS in sorghum reveals common genetic control of grain size among cereals

• DOI: 10.1111/pbi.13284
• Publication Date: 2019-10-29T06:20:20Z
• Authors: Yongfu Tao; Xianrong Zhao; Xuemin Wang; Adrian Hathorn; Colleen Hunt; Alan W. Cruickshank; Erik J. van Oosterom; Ian D. Godwin; Emma S. Mace; David R. Jordan
• Keywords: grain size; 2. Zero hunger; 0301 basic medicine; 0303 health sciences; QTL; Seeds. Seed technology; cereal crops; Quantitative Trait Loci; 03 medical and health sciences; orthologues; Phenotype; 669; 1110 Plant Science; Seeds; 1305 Biotechnology; Genetics; GWAS; Methods and systems of culture. Cropping systems; sorghum; 1102 Agronomy and Crop Science; Research Articles; Genetic Association Studies; Sorghum

SummaryGrain size is a key yield component of cereal crops and a major quality attribute. It is determined by a genotype’s genetic potential and its capacity to fill the grains. This study aims to dissect the genetic architecture of grain size in sorghum. An integrated genome‐wide association study (GWAS) was conducted using a diversity panel (n = 837) and a BC‐NAM population (n = 1421). To isolate genetic effects associated with genetic potential of grain size, rather than the genotype’s capacity to fill the grains, a treatment of removing half of the panicle was imposed during flowering. Extensive and highly heritable variation in grain size was observed in both populations in 5 field trials, and 81 grain size QTL were identified in subsequent GWAS. These QTL were enriched for orthologues of known grain size genes in rice and maize, and had significant overlap with SNPs associated with grain size in rice and maize, supporting common genetic control of this trait among cereals. Grain size genes with opposite effect on grain number were less likely to overlap with the grain size QTL from this study, indicating the treatment facilitated identification of genetic regions related to the genetic potential of grain size. These results enhance understanding of the genetic architecture of grain size in cereal, and pave the way for exploration of underlying molecular mechanisms and manipulation of this trait in breeding practices.