SSR Markers Mapping And Genetic Analysis Of Resistance To Powdery Mildew Gene In Common Wheat WP6192

Wheat （Triticum aestivum L.） is one of major grain crops in China; its production isrelated to the national economy and the people’s livelihood. Powdery mildew leads to loweryield and quality of wheat and affects wheat production, which caused by Blumeria graminis f.sp. tritici. Breeding resistance is the most economical and environmental method forcontrolling, and the vital guarantee for sustainable development of agriculture. Wild relativesof wheat are an important source of powdery mildew resistance genes, which is significanceto improvement of common wheat powdery mildew resistance. The subjects of this study arethe resistance material WP6192that is derived from the cross of Triticum polonicum L.×Zhong13. Genetic analysis of its resistance to powdery mildew and linkage analysis of theWP6192by a use of wheat SSR markers for chromosomal positioning were be researched inthis paper. The results were presented below:1. The resistant WP6192as female parent and the susceptible Xiaoyan166as male parent,that all F₁plants of WP6192×Xiaoyan166and BC₁plants of WP6192/Xiaoyan166//WP6192, which was high resistant to powdery mildew after artificial inoculation shownthat the resistance of WP6192was dominant. One hundred and thirty-three plants wereresistant and forty-nine plants were susceptible to powdery mildew in F₂. Chi-square testindicated that the ratio of resistance and susceptibility was3:1. In addition, the ratio ofresistance: susceptibility was1:1in the BC₁of WP6192/Xiaoyan166//Xiaoyan166. AsZhong13is susceptible to powdery mildew, the resistance gene of WP6192comes fromTriticum polonicum L. So, resistance to powdery mildew of WP6192was controlled byone dominant gene which was temporarily designated as PmWP6192.2. DNA samples extracted from leaves of the F₂population were extracted and ten each ofresistant and susceptible individuals DNA were pooled into two separate groups forbulked segregation analysis （BSA）. Of894pairs of SSR markers, there were262pairswith polymorphism between parents by bulk segregation analysis. Nine of262pairs ofpolymorphic SSR markers including Xgwm515, Xgwm249, Xgwm425, Xgwm372, Xgwm630, Xbarc10, Xbarc201, Xbarc220and Xbarc353were found to be linked toPmWP6192. According to the chromosomal sites of the linked SSR markers, theresistance gene was located on chromosome2AL.3. Linkage analysis showed that these nine polymorphic SSR markers including Xgwm515,Xgwm249, Xgwm425, Xgwm372, Xgwm630, Xbarc10, Xbarc220, Xbarc201and Xbarc353have the estimated genetic distance of30.5cM,9.6cM,9.3cM,7.6cM,5.6cM,5.3cM,5.0cM,4.0cM and2.3cM, respectively. These markers were associated with PmWP6192in an order of Xgwm249â†'Xgwm425â†'Xgwm372â†'Xgwm630â†'Xbarc10â†'Xbarc220â†'Xbarc201â†'Xbarc353â†'PmWP6192â†'Xbarc515. And the nearest marker fromPmWP6192was Xbarc353with genetic distances of2.3cM.4. It had been reported that Pm4resistance gene loci including Pm4a and Pm4b were locatedon chromosome2AL also. It was clear that PmWP6192differed from Pm4by allelism testusing molecular markers. The results of this study confirmed that PmWP6192might be anovel resistance gene to powdery mildew.