TaFlo2-A1, which is represented by two haplotypes in our study, was found to be significantly associated with TGW. Polymorphisms of an 8-bp InDel in the promoter and of five SNPs in the first intron were observed in TaFlo2-A1. The orthologs TaFlo2-B1 and TaFlo2-D1 lacked sequence variations associated with TGW (Fig. 2b). The association analysis of the Chinese Micro Core Collection (MCC) and Pakistani accessions indicated that TaFlo2-A1b was the superior haplotype for TGW. Nevertheless, some accessions that contained TaFlo2-A1a also had high TGW. This is mainly because the effect of TaFlo2-A1 is likely masked by other genes associated with grain size .