Evaluation of Fruit Rot Disease Resistance in Muscadine Grapes (Vitis rotundifolia Michx.), Poster Board #386

Musacadine grapes (Vitis rotundifolia Michx.) are truly a sustainable fruit for the southeastern United States. Although far more resistant to many fungal and bacterial diseases and pests than most of the bunch grapes (V. vinifera, V. labrusca, or their derivatives), muscadine grape suffers considerable economic losses every year due to berry rotting diseases such as black rot (Guignardia bidwellii f. muscadinii), bitter rot (Greeneria uvicola), and macrophoma rot (Botryosphaeria dothidea), which could significantly decrease yield and affect their marketability. The objectives of this study were to evaluate commercial muscadine grape cultivars for fruit rot resistance in order to identify promising muscadine germplasm for use in the breeding program and to make cultivar selection decisions for grape growers.  Among the cultivar evaluated,  bitter rot was the most prevalent fruit rot disease that occurred on 38 muscadine grape cultivars, followed by black rot, and the incidence of macrophoma rot was relatively low. The most susceptible cultivar to bitter rot was ‘Early Fry’, while cultivars ‘Pride’, ‘Noble’, ‘Albemarle’, ‘Sothern Home’, and ‘Cowart’ showed some degree of resistance to the bitter rot disease. In addition, ripe rot is also commonly found on the muscadine berries, especially at the late harvesting season, which often makes the identification of bitter rot more difficult.