Potential resistance sources for powdery mildew disease of sainfoin.

Sainfoin is an important forage crop in Turkey. Powdery mildew is one of the diseases that affects sainfoin quality and yield. In this study, 119 sainfoin genotypes containing64 different sainfoin species, subspecies and varieties and 9 Onobrychis species with no species identification were evaluated for their susceptibility to powdery mildew disease under field conditions in Ankara province, Turkey, during the years 2009-2011. These genotypes were obtained from different locations. The causal agents of the powdery mildew species observed on sainfoin species were identified as Erysiphe trifolii and Leveillula taurica. Erysiphe trifolii caused disease on 6 species, 2 varieties and 1Onobrychis sp. Leveillula taurica caused disease on 13 species, 2 varieties, 1 subspecies and 1 Onobrychis sp.Eleven sainfoin species, 1 variety, 2 subspecies and 7Onobrychis sp. were infected by both fungi. Powdery mildew disease was observed on some of the genotypes of same species obtained from different regions, however, no disease was present some of the other genotypes. No powdery mildew disease was observed in 20 species, 1 variety and 3 subspecies of sainfoin. Species, varieties, subspecies and different genotypes without disease symptoms should be evaluated as the resistance sources for powdery mildew.