The Molecular And Celluar Biological Mechanism Of Wheat Resistance To Stripe Rust, Powdery Mildew And Senescence

Wheat is one of the earliest crops to be domesticated and it also is the most important food crop worldwide. In China, wheat is also a very important crop in agriculture, which is the second only following rice. Thus, wheat plays a key role on developing economy and sustaining society stability and prosperity. In order to increase wheat yield and improve quality, breeders are trying their best to breed varieties tolerant to biotic and abiotic stress. Stripe rust, caused by Puccinia striiformis, and powdery mildew is caused by the fungus Blumeria graminis f. sp. Tritici. , are the most important diseases of wheat (Triticum aestivam L em Thell) worldwide. The best method to control stripe rust is to develop new cultivars carried resistance genes. However, it is a common view that genetic basis of wheat resistance to current prevailing physiological races of these pathogens is very narrow and it has limited the wheat production in our country. So it is very important to find new resistant genes to stipe rust and powdery mildew. Many studies have been proved that the local wheat varieties and foreign chromosome are rich and valuable resistance gene pool to stripe rust and powdery mildew and have large exploited potential for wheat resistance breeding. Leaf senescence, encompassing a period from maturation to attrition, severely decrease grain development and wheat yields, which shorten the efficient photosynthesis period of wheat (Triticum aestvum L.) and coincides with the onset of initiation of grain filling. The purpose of this study is to determine molecular and celluar basis for the resistance to the outer-biological factor adversity (stripe rust and powdery milew) and the inter-biological factor adversity (senescence). The results are given as follows:1 Analysis of genetic composition of several wheat materials resistant to puccinia striiformis27 parents, 51 F₁ populations, 42 F₂ populations and 3 backcross F₂ populations were screened with seven current prevailing stripe rust strains (CY30,CY31 ,CY32, HIII,HIV,S4 and S14). Resistance response of parents show that cultivars (R25, R57, R59 and R88) and lines (Xingkang5, 4285, AIM5, AIM6 and Wen-1) were immune or iso-immune to stripe rust while lines (Neixiangl88, Annong91168, Shan253, Lu955159, BeiZ76, Yanful88, Wenmai6, Shu3110, Huaiying9628, Yumai47, Yumai62, Gaochen8901 and Chinese Spring) were highly susceptible or fully susceptible to stripe rust. The results of inheritance analysis, companying the different infection type (IT) of them and their derivatives, displayed that there were four different resistances to stripe rust in parents: â‘ ...