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The TGW6 in rice determines grain weight, and encodes a novel protein with indole-3-acetic acid (IAA)-glucose hydrolase activity.TaTGW6 was considered as a candidate gene related to grain development in wheat.Based on the conserved region of TaTGW6 homologous sequences, primers were designed to amplify TaTGW6 gene in wheat.Our results showed that TaTGW6 shares the same functional domains with rice TGW6 and three alleles of TaTGW6 were detected, designated TaTGW6-a, TaTGW6-b and TaTGW6-c.The TaTGW6-a has 1035-bp coding sequence and no intron with low grain weight.Compared with the TaTGW6-a, the TaTGW6-b contains 6-bp insertion in exon associated with high grain weight, and has low frequency distribution in modern varieties.The TaTGW6-c is a deletion type related to high grain weight.The TaTGW6 was located on chromosomes 4AL using a RIL population from Jing411×Hongmangchun21, and a set of Chinese Spring nullisomic-tetrasomic lines.It was linked to the SSR locus Xbarc1047 with a genetic distance of 6.62 cM, explained 14.3-21% of the phenotypic variation in three environments.The TaTGW6 was also validated to be associated with grain weight using a natural population and Chinese wheat mini-core collections by association analysis, explained 7.7-9.6% of the phenotypic variation in three environments.Further study indicated that TaTGW6 had more significant effect on grain width than grain length.Real-time PCR revealed the expression level of TaTGW6 was negatively correlated with grain weight at middle and later stages of grain development.The novel functional marker developed here can be used for MAS in wheat to improve grain weight and also facilitate our understanding of the regulatory mechanism underlying grain weight.