Mapping and Characterization of QTLs for Awn Morphology Using Crosses between "Double-Awn" Wheat 4045 and Awnless Wheat Zhiluowumai.

Awns play important roles in seed dispersal, protection against predators, and photosynthesis. The characterization of genes related to the formation of awns helps understand the regulation mechanisms of awn development. In the present study, the "double-awn" wheat 4045, which features super-long lemma awns and long glume awns, and an awnless wheat line, Zhiluowumai, were used to investigate QTLs or genes involved in awn development. QTL analysis identified three loci-, , and -using a population of 101 4045 × ZLWM F plants. Fine mapping with a total of 9018 progenies narrowed the mapping interval of to an 809-kb region, which was consistent with the locus, containing five genes on chromosome 5AL. Gene structure and expression analysis indicated that was the causal gene, which was subsequently verified by overexpression of in a "double-awn" wheat, Yangmai20. The retained "double-awn" phenotype of transgenic plants suggested that represses the elongation but does not influence the emergence of the awns. Moreover, 4045 harbors a new allele of with a 261-bp insertion in the promoter region and a lack of the EAR2 motif in the encoding region, which influences several important agronomic traits. In this study, we identify two novel QTLs and a novel allele of , providing new resources for exploration of awn development.