Genome-Wide Association Study of Flowering Time in Hexaploid Winter Wheat

In order to achieve successful sexual reproduction and grain set, plants must be able to flower at the proper time. The optimal flowering time is supposed to have a critical adaptive value for plants. In order to detect loci related to flowering time, we divided flowering time into eight floral developmental stages: double ridge stage (DR), terminal spikelet stage (TS), white anther stage (WA), green anther stage (GA), yellow anther stage (YA), tipping stage (TP), heading stage (HD) and anthesis (AN). 210 genotypes are employed to determine the eight floral developmental stages in the greenhouse. Thermal time is used to access the time of floral developmental stages. Around 8000 SNP markers were selected based on 90k chip to genotype the 210 genotypes. Genome-wide association studies showed some markers are significantly and consistently related to the eight floral developmental stages. These SNP markers, which are closely associated with the eight floral developmental stages, are mainly on chromosome 1A, 3B, 5A. However, SNP markers which are significantly related to duration of DR-AN, TS-AN, DR-TS are variable. Furthermore, we will utilize synteny between wheat and other grass species genomic sequences for mapping and sequencing of deduced candidate genes. In the future, double haploid population will be set up to validate our GWAS results.