To associate TaFlo2-A1 with TGW, two natural populations, the Chinese Micro Core Collection (MCC) and the Pakistani collection, were used. In the MCC, the homozygous TaFlo2-A1a haplotype was found in 219 (83.5%) accessions, whereas the TaFlo2-A1b haplotype was found in 43 (16.5%) accessions. In the Pakistani wheat collection, the number of accessions carrying TaFlo2-A1a and TaFlo2-A1b were 85 (64.6%) and 45 (35.4%), respectively. Both in the MCC and Pakistani collections, the positive haplotype TaFlo2A-A1b had a lower frequency, which showed the scope of improving grain weight.