Screening of grape powdery mildew resistant materials by field natural identification combined with molecular markers

To confirm the suitable conditions for field identification of the grape powdery mildew, and screen effective molecular marker probe for powdery mildew resistance in grape, 8 cultivated grape varieties (Zaoheibao, Qiuhong Bao, Wanheibao, Jinghongbao, Wuhe Cuibao, Lihongbao, Summer Black, Crimson Seedless) and 2 wild grape varieties (Hejin -1 and Beibinghong) were selected as study materials. By setting different temperature gradient (4, 20, 24, 28, 32, 36℃), the grape leaves were infected by artificial living body of powdery mildew fungus. The agar glass slide method was used to germinate and culture the spores of powdery mildew fungus. And then the germination and infection dynamics were observed. Field natural identification and seedling stage molecular markers (grape powdery mildew resistant RAPD marker OPW02-1756, SCAR marker SCO11-914) were combined to classify and compare the resistance among the 10 grape varieties. The results showed that the optimum temperature of grape powdery mildew spore germination was 32℃. Beibinghong and Hejin -1 were highly resistant varieties (HR). Qiuhongbao and Wanheibao were part of the high sensitive varieties (HS). The others were medium resistant varieties (MR). Moreover, grape powdery mildew resistant RAPD markers OPW02-1756 was applicable for the detection of powdery mildew resistance on Qiuhongbao, Zaoheibao, Wanheibao, Jinghongbao, Lihongbao, Wuhe Cuibao, Summer Black, Crimson Seedless and Hejin -1 but inapplicable for Beibinghong. As for grape powdery mildew resistant SCAR markers SCO11-914, it was applicable for the detection of powdery mildew resistance on Beibinghong and Hejin -1, but inapplicable for Qiuhongbao, Zaoheibao, Wanheibao, Jinghongbao, Lihongbao, Wuhe Cuibao, Summer Black and Crimson Seedless. Both of them were applicable for Hejin -1 grape. The results provide some material and theoretical fundations for grape powdery mildew resistance breeding and hybrids identification. (authors)