Molecular mapping of tenacious glumes, Tg: a gene involved in the evolution of the free-threshing character of common wheat.

摘要

Synthetic hexaploids derived from hybridizations between tetraploid wheat (Triticum turgidum L.) and Aegilops tauschii Cosson are non-free-threshing. Glume tenacity and the non-free-threshing characteristic in synthetics, carrying Q or q, are due to the action of tenacious glumes, Tg, a semi-dominant gene on chromosome 2D of Ae. tauschii. Although the sequence of events leading to the evolution of free-threshing hexaploid bread wheat (Triticum aestivum L.) has not been determined, current evidence suggests that at least two mutations, q to Q and Tg to tg, were necessary to generate free-threshing hexaploid wheats with the QQtgtg allelic constitution. Given the important role that Tg has played in the evolution of bread wheat, we have initiated a project to use map-based methods to isolate and characterize this gene. In this study, we mapped 10 SSR markers and localized Tg to a region flanked by Xgdm5 and Xwmc25.