Molecular Detection Of Resistance Genes And Reactions Of The Wheat Cultivars To Powdery Mildew

Wheat powdery mildew,caused by Blumeria graminis f.sp.tritici.is one of the most important wheat diseases in the worldwide,which could result in5～19%of yield loss,occurred seriously period cut up to30%. Causing serious economic losses.Although There are many ways control of wheat powdery mildew in agricultural production, the use of resistant cultivars is an effective, economical,and environmentally safe approach. However, The powdery mildew races widely, adapted and mutated fastly.Which lead to the main problems of wheat production in our country are single resistance source, unreasonable resistance genes layout, and the effective powdery mildew gene has not yet been fully used, so we desperately need to comprehensive understand of our existing wheat materials, in-depth analysis, combined with the results of wheat resistant materials improved resistance sources, gene integration in wheat breeding, and explore new effective resistance genes. This knowledge could lead to a more efficient strategy in wheat breeding for durable resistance to powdery mildew. In this study, Used in vivo and in vitro leaf segments inoculation the two methods to test materials resistance identification, and used PCR method based on genetic linking molecular markers tightly linked with Pm2,Pm4,Pm13,Pm21,Pm30andPm34,a total of six powdery mildew resistance gene and eight pairs of primers to identifications of resistance genes.the80of wheat resistant cultivars or lines from all over the years were collected by our Laboratory. The results as following:(1)Identification Resistance of wheat cultivars(lines) materials:Using in vivo and in vitro leaf segments inoculation the two methods to test in collection of80wheat cultivars(lines) materials.The statistical results of identification of Vivo inoculation showed, in80wheat cultivars(lines) materials,3with immune (I)(accounting for3.75%),18with high resistance (HR)(accounting for22.5%),23with moderate resistance (MR)(accounting for28.75%)、20with moderate susceptivity(MS)(accounting for25%) and16with high susceptivity (HS)(accounting for20%).The statistical results of identification of in vitro leaf segments inoculation showed, in80wheat cultivars(lines) materials,11with immune(I)(accounting for13.75%)、25with high resistance (HR)(accounting for31.25%),23with moderate resistance (MR)(accounting for28.75%)、18with moderate susceptivity (MS)(accounting for22.5%) and3with high susceptivity (HS)(accounting for3.75%).Therefore, most wheat cultivars(lines) materials were ranked to be moderate resistance.(2)Pm gene contained in these wheat cultivars(lines) materials was identified by the PCR based markers tightly linked with Pm2, Pm4, Pm13, Pm21, Pm30andPm34. Among these wheat cultivars(lines) materials,71were tested with Pm2gene (accounting for88.75%),58were tested with Pm21gene (accounting for72.5%),78were tested with Pm30gene (accounting for97.5%),77were tested with Pm34gene (accounting for95%),only a few cultivars contain Pm4and Pml3. In addition, experimental studies have shown that most of the tested wheat cultivars(lines) materials have multiple resistance genes in one material, in particular those materials with four or five resistance genes, respectively,accounting for38.75%and30%. there is not detected one of wheat varieties carry one resistant gene in this test.(3)According to the results by molecular detection of resistance genes and reactions of the Wheat Cultivars to Powdery Mildew,14with immune (I) or high resistance (HR) and24with moderate resistance (MR) by two identification resistance methods to test in collection of80wheat cultivars(lines) materials.those materials with two or more resistance genes polymerization were detected.The main types of genes polymerization(Pm2+Pm13+Pm21+Pm30+Pm34, Pm2+Pm13+Pm30+Pm34、Pm4+Pm21+Pm30+Pm34and Pm2+Pm4+Pm13+Pm21+Pm30+Pm34), it was indicated,which performed well and stable resistance,The types of Pm2+Pm30+Pm34genes polymerization showed unstable and poor resistance.So The resistant genes widely existing in wheat cultivars(lines) materials consisted of Pm2、Pm30、Pm34behaved unstable and poor resistance,and their resistance were gradually disappearing,while the resistant genes Pm4、 Pm13、Pm21performed well and stable resistance in the test,in particular those resistant genes got together with diverse form.