The Effect Of Cultivar Diversity On Wheat Powdery Mildew And The Population Diversity Of The Pathogen In The Field

Wheat powdery mildew is a worldwide wheat disease caused by Blumeria graminis f.sp.tritici. In recent years, due to the large-scale climate change, changes in cropping patterns andother reasons, the area and the degree of harm of this disease have been maintained at a high levelcausing serious damage. Mixed cultivation can be effective for powdery mildew control byincreasing the diversity of species and more secure compared to traditional control methods.Compared with the traditional control methods, pollution of the environment can be minimized.Research on impact of hybrid varieties on yield, protein and control effects of powdery mildewprovides a theoretical basis and technical support for the use of species diversity to controlpowdery mildew continuously. We selected eight wheat varieties with different disease resistanceand greater difference in the genetic background with3,4,5,6,7or8varieties in eachcombination in2002and2003. after artificial inoculation mixed powdery mildew, we comparedthe effect of hybrid of different resistance varieties on AUDPC value of wheat powdery mildew,wheat production, crude protein content, grain weight and panicles. Standard samples werecollected of wheat powdery mildew in the field. Changes in populations of wheat powdery mildewunder the diversity of growing conditions were studied by SSR markers. The results are asfollows:1. Hybrids of different varieties showed different control effect and different kinds ofvarieties had different effect on control effect.42.44%of all hybrid combinations had controleffect with the relative control effect amounted to1.23-26.77%in2012.75.00%of all hybridcombinations had control effect with the relative control effect amounted to1.76%-45.40%in2013.2. The analysis of yield showed that the actual value of13combinations was greater than thetheoretical value with growing rate0.24-14.59%in2012. One combination was significantlydifferent. The actual value of71.43%combinations were greater than the theoretical value withgrowing rate0.94-16.62%in2013. Seven combinations were significantly different.3. In the analysis of grain weight,50.00%of grain weight measured value was greater thanthe theoretical value of the portfolio with increasing rate0.03%-9.32%in2012. One combinationwas significantly diffenrent.67.79%of grain weight measured value was greater than thetheoretical value of the portfolio with increasing rate0.01%-9.10%in2012. One combination wassignificantly diffenrent.4. The analysis of small spikes showed that the actual value of96.43%combinations weregreater than the theoretical value with growing rate2.93-20.71%. No. Five combinations weresignificantly different.5. The analysis of the content of crude protein showed that the actual value of80.77%combinations were greater than the theoretical value with growing rate0.59-5.23%which was nosignificant difference in2012. the analysis of the content of crude protein showed that the actual value of75.00%combinations were greater than the theoretical value with growing rate0.54-5.43%which was no significant difference in2013. the correlation analysis between the the content ofcrude protein and mixed planting control effect showed there were no significant difference.Therefore, wheat hybrids had some effect on yield, but no effect on the1000grain weight, earnumber and protein content.6. In this study, we studied pure line varieties of wheat grown and powdery mildewpopulations in mixed planting combinations. When planted in pure line, wheat powdery mildewpopulation genetic richness of diversity was related to the complexity of the genetic background ofwheat varieties. When the number of cases of powdery mildew population groups was more, theproportion of the dominant populations was less. Genetic diversity of erysiphales in mixedplanting combinations was higher than that in pure line combinations. Mixed cultivation can easethe host pathogen selection pressure on white, it remained at a relatively stable state of equilibrium,but the combination of the genetic background of the richness of the various wheat varieties willhave a direct impact on wheat powdery mildew levels of genetic diversity. Therefore, to make thewheat pathogen produces stabilizing selection we can choose the complex genetic background ofwheat varieties and not simply by increasing the number of hybrid varieties to achieve.