QTL Mapping For Strong Seed Dormancy Of Tibetan Semi-wild Wheat

Pre-harvest sprouting (PHS) is a worldwide disaster of wheat. A lot of research has been done on it around the world, which has identified abundant QTLs for seed dormancy and pre-harvest sprouting tolerance. However, the discovery of new major QTL has become more and more difficult for lack of the new resistant resources. Tibetan semi-wild wheat (T.aestivum ssp. tibetanum Shao) is a kind of special semi-wild hexaploid wheat resources, which was strong seed dormancy but it was little reported. This study mainly reported the result of QTL mapping for strong seed dormancy in Tibetan semi-wild wheat accession Q1028. A high density genetic map of Tibetan semi-wild wheat is constructed using a recombinant inbred line (186 lines, F9-F12) populations, which are derived from the cross of Tibetan semi-wild wheat accession Q1028 with non-dormant common cultivar wheat ZhengMai9023 (ZM9023), and multiple types molecular markers (DArT and SSR). And then, dormancy data of different after-ripening stages was used to identify the major QTLs in Q1028. The results indicate that:1.A total of 6 major QTLs for seed dormancy were identified in Tibetan semi-wild wheat accession Q1028. The QTLs were designated as Qsd.sau-1B, Qsd.sau-3A, Qsd.sau-3B, Qsd.sau-4A1, Qsd.sau-4A2 and Qsd.sau-7A, which were detected on the chromosome 1BL, 3AL,3BL,4AS,4AL and 7AL, and explained 8.9%,6.6%,6.1%,11.4%,9.4%,12.7% phenotypic variation in the general average rate, respectively. Furthermore, Qsdsau-IB, Qsd.sau-4A1 and Qsd.sau-7A were few reported in domesticated common wheat.2.The dormancy data of different after-ripening stages showed a significant difference in detection efficiency of QTL. The data of middle after-ripening stage and average could identify most QTLs, which meaned they were most effective. And the second was early after-ripening stage. The late and end after-ripening stage were relatively inefficient.3.The difference between dormancy effect durations of several QTLs in the study was objective reality. The long dormancy effect duration of QTL might be not suitable for summer propagation of wheat. The QTL, which was strong intensity and short duration in dormancy, should be more attended in PHS resistance breeding.