Genetic Analysis And Chromosomal Location Of Two New Genes For Resistance To Powdery Mildew In Wheat (Triticum Aestivum L.)

Powdery mildew caused by Erysiphe graminis (DC) E. O. Speer f. sp. tritici E'm. Marchal, is one of the most important wheat (Triticum aestivum L. em Thell) diseases in many regions of the world. In recent years, the powdery mildew harms has become worse and worse in china wheat cultivation, and it has become one of major desease that threaten china wheat produce and food safety. The use of resistant cultivars is the most economical, efficient and environmentally safe way to control powdery mildew. Wild relatives of wheat have a large of resistance resources, and are a rich gene source for powdery mildew resistance. Elytrigia intermedium is one wild relatives of wheat, it is a good resistance resource to wheat diseases, and itsE group chromosome have immune resistance gene to powdery mildew. A new wheat line YU25, which derived from a wide cross between a wheat cultivarCM107 and octoploid Trititrigia TAI7047 (Taiyuan768/ Elytrigia intermedium//76(64)), exhibit immune to wheat powdery mildew. Genetic analysis of its resistance to powdery mildew and linkage analysis of its resistance genes were be researched in the present study. The main results are summaried as follows:By common analysis methods of classical genetic, the line YU25 was crossed with a susceptive wheat cultivar Mianyang 11 (MY11) and backcrossed both with MY11 and YU25 to produce their F₁, F₂, BC₁F₁, BC₂F₁ populations and MY11, YU25, CM107, TAI7047, Taiyuan768,76(64), Elytrigia intermedium, which were grown in greenhouse and inoculated by the epidemic predominant race of powdery mildew in Southwest China. The response patterns of F₂ population showed that the I (immune) : R (resistant) : S (susceptible) segregation ratio closely fit to 12 : 3 : 1, suggesting that the wheat line YU25 carried two different dominant resistance genes to powdery mildew, one of them exhibited immune and the other showed highly resistant. The results was also supported by the 2 :1 :1 separation ratio of I: R : S in the BC₁F₁ population. Another result shows that the two genes have originated...