The Use Of Wheat Cultivar Mixtures For The Wheat Powdery Mildew Control And RGA Analysis

Cultivar mixture is one of the most economical and effective measures for disease control and yield increase. A field experiment was designed to test the effects of cultivar mixtures, inoculated with Blumeria graminis f.sp. tritici, on the epidemics of the polycyclic disease and the grain yield. Chancellor and Bao Feng 104, a susceptible and a resistant line, were mixed at the ratio of 1:0, 0:1, 1:1, 1:2 and 2:1 and replicated for three times. The experimental plots were designed as randomized blocks. The results provide strong evidence that cultivar mixtures were useful for suppression of the disease. By the resistant mechanism research and analysis of Cultivar mixtures , the results provide that density effect or block effect or induce resistance are resistant mechanism.The density effect is the domain mechanism and other resistant mechanism in the growth of latter stage by the study. Data for the area under disease progress curve (AUDPC) and the rate of epidemics showed that the ratio 1:2, Chancello: Bao Feng 104, was the most significant for the disease control. The grain yield, however, did not show any increase in every of the ratios tested. The reasons for this need to be studied further.The genetic diversity of 76 wheat varieties was studied using resistance gene analogue (RGA) analysis based on the conservative sequences, nucleotide binding site (NBS) and leucine-rich repreats (LRR), of resistance gene RPS2 of Arabidopis thaliana and tobacco N gene resistant to TMV. The clustering result showed that all of the varieties were divided into 4 lineages according to the DNA band data at the level of 85% dissimilarity. The information from this study may be useful in wheat powdery mildew control by mix-planting different varieties in a field and breeding for resistance varieties by the means of using parental varieties with different resistance gene analogues.