Abstract
Downy mildew, caused by the fungal pathogen [Plasmopara viticola (Berk. & Curt.) Berl. & de Toni], is one of the most damaging diseases worldwide in grapes (Vitis L.). It not only adversely affects grapevine ecological characteristics but also lowers the fruit yield, berry quality, wine-making property, and consumer consumption appearance. This study evaluated downy mildew disease resistance in 182 F1 plants of a cross combination C30-5-1 × ‘Chardonnay’ based on a scale of 0–5 with 0 score: clear leaves, no sign of any kind of disease symptoms; 1: few single spores on a single leaf; 2: more than 10 single separated incidents of spores on a single leaf; 3: clustered incidents of spores covered more than 50% of a single leaf area; 4: incidents of spores covered more than 75% of a single leaf area; 5: over 75% of a single leaf area was covered by spores. Both parents were used as control. The results indicated that downy mildew resistance varied in F1 offsprings of C30-5-1 × ‘Chardonnay’, which gives us hope for selection of downy mildew resistant grape cultivars or germplasm in our disease resistant grape breeding program.
