معرفی ارقام مقاوم هلو به قارچ عامل بیماری سفیدک پودری هلو Podosphaera pannosa (Wallr.) de Bary

In order to evaluate ۲۵ peach varietiesagainst powdery mildew an experiment was conducted in randomized complete block design with three replications under natural infection condition in the Meshginshahr Agriculture and Natural Resources Research Station during ۲۰۱۴ and ۲۰۱۵. The peach varietieswere consist of Robin, Red haven, Early red, Spring crest, Vesevio, Red top, J.H. Hale, Shasta, Early glo, Amesdn, Loring, Spring time, Velvet, Sudanell, sundance, Anjiri, Haj Kazemi, Paeizeh, Elberta, Baby gold۷, Dixi red, Red skin, Sabz-e- Mashhad, Sun crest and July Elberta. Combined analysis of variance showed that disease severity of powdery mildew among varieties was significantly different at the ۱% probability level. Based on mean comparisons, varietiesRed haven, Anjiri, Early glo, J. H. Hale, Loring, Red top, July Elberta, Velvet, Spring crest, Red skin, Shasta, Early red, Sudanell and Elberta had lower mean disease severity of powdery mildew on leaves compared to other varieties. Based on cluster analysis, varietiesEarly glo, J. H. Hale, Red haven, Anjiri, Loring and Red top were classified as very resistant and July Elberta, Vesevio, Elberta, Spring crest, Velvet, Shasta, Early red and Red skin as resistant varietiesto causal agent of peach powdery mildew.