Discovery And Molecular Tagging Of New Earbranching Gene In Natural Barley Mutant

Barley is one of the important genuses in Triticeae,and also one of the oldest cereal crops in the world, and ranks fourth after wheat, maize and rice as the most important grain crop. As economic crop and one of the common model plants in genetic research, barley is increasingly gainning more and more attention of researchers from home and abroad.Selection and breeding of high-yield varieties is the objecive that barley researchers have been going in for.Breeding for No. of spikes is one of the primary strategies of high-yield breeding.Therefore, the exploitation and breeding of branching varieties can lay important foudation in high-yield barley breeding.Barley branching types can be summed up two types: one is general branching type,which outgrows spikes from branching stem;another is earbranching type.In the latter,earbranching barley with branching spike has the better value in high-yield breeding. f151,a natural barley mutant,found in 1996 in the population of six-rowed Qingke landrace "Xueerdong "(ZDM08757) which was planted on Duoying farm of Sichuan Agricultural University, has better structural features of ear and more important value in barley breeding.The investigations and genetic analysis of earbranching trait were carried out in the populations of F1, F2, B1and B2 which were produced by crossing including reciprocals and backcrossing between f151 and each of "Qipangou" (ZDM0863), ''Yaanwanwanmai"(ZDM08953) and "Gateway" .The results showed that earbranching trait of fl51 was controlled by one pair of recessive genes without cytoplasm effects.In this study, the linkage between the earbranching gene and the SSR marker HVM40 on the short arm of chromosome 4H was found by bulked segregated analysis using SSRmarkers based on the F2 population of the hybrid " f151 X Gateway " . Partial genetic linkage map of chromosome 4H was constructed by linkage analysis of F2 population further using the SSR marker HVM40 and RFLP markers on the short arm of barley chromosome 4H and SSR markers on the fouth linkage groups of wheat. And the gene was further flanked by the SSRmarker HVM40 and the RFLP marker CDO669 on the short arm of chromosome 4H, with map distances of 8.7cM and 5.8cM , respectively. The gene, which was first discovered and located, is temporarily named "mb" .