Identification Of New Germplasm For The Resistance To Powdery Mildew And Genetic Analysis In Wheat (Triticum Aestivum L.)

Wheat powdery mildew, caused by Blumeria graminis f.sp.tritici, is one of the most important diseases in the world, which spread abroad through the air. In recent years,with the development of the condition of the irrigation and fertilizer, level of the cultivation, density of the plant,wheat powdery mildew has become a primary disease in the aspect of the security of wheat productin, and be harmful increasingly to food security in China. It is the economical, effective and safe method that selecting and cultivating resistance cultivar to prevent and cure the wheat powdery mildew.The multiplicity of powderyy mildew physiological strain induced the fact that powdery mildew has an obvious physiological differentiation, wide adaptability, the change of the toxic within the colony was fast as the variety of the host, the lost of the resistance controlled by a single gene leads to the result that the resistance in the wheat cultivar was conquered continuously by the new virulent gene. The exploration of the diverse anti-source and identification of new resistance gene, selection of the endurable resistance cultivar with multiple resistant genes play a key role in the selection of resistance cultivar.Genetic analysis of resistance, SSR were adopted for the generations ,which derived from a cross and back cross among 1002, 1003 and 970. The generations, which derived from a cross among the created wheat, imported wheat ,rye, Elytrigia intermedium ,were used as the research material. We expected the new gene resources with resistance to powdery mildew would be found to be affluent in resistant genetic basis of wheat cultivar in China by the way of identification of the resistance to powdery mildew, molecular-cytological identification of the exogenous germplasm.The main results are summaried as follows,1 The F₁,F₂,F₃,BC₁F₁,BC₂F₁ populations, which derived from cross and back cross between two susceptive wheat cultivars Mianyang 11 (MY11), SY95-71 and three resistant lines 1002,1003,970 were researched in the present study. Basing on the resistance to powdery mildew, we made a genetic analysis of the resistant material. The result showed that the strain 1002,1003 contained a pair of dominant gene, respectively, which was immune to the popular physiological strain of powdery mildew. The strain 970 contained a pair of recessive gene, which high resistant to powdery mildew.2 Analysis of prolamin from seed and SSR showed that the strain 1002, 1003 didn't contain 1BL/1RS translocated chromosome, with the characteristic band of PmE SSR marker linked, the strain 970 contained 1BL/1RS translocated chromosome, without the characteristic band of PmE SSR marker linked.3 We identified and obtained 28 high resistance to powderyy mildew materials, 18 immunity and near immunity to powderyy mildew materials,1 immunity ,3 high resistance to stripe rust, 11 middle resistance to stripe rust from the generations of the 76216-946/7045//jinzhou411BCF₃ and My15/ Chinese Baili Rye//My15BC₂F₄, which derived from the wide cross among the imported wheat cultivar.4 We identified 3 plants with the resistace to powdery mildew by the way of the cytological identification and the analysis of genomic constitution. It was concluded that a set of genome was lost in natural condition and we obtained two hexaploid tritical 2n=42, one wheat-rye addition line 2n=44.In summary, it settle the foundation for genetic studies on the resistance, provide the medial material and parent selection for improvement of breeding for disease resistance. It will play a key role in wheat breeding.