EVALUATION OF GRAPE ROOTSTOCKS FOR RESISTANCE TO PIERCE'S DISEASE AND ADAPTATION TO NORTH FLORIDA ENVIRONMENT
To understand the adaptation of grape rootstocks commonly used in major grape production areas worldwide to Florida, where the growing season is hot and humid that favors the prevalence of Pierces Disease (PD), ten major grape rootstocks were evaluated for their PD resistance and growing performance at the experimental vineyard, Florida A&M University, Tallahassee, Florida. Leaf necrosis of Pierces disease was observed among all the rootstocks tested, but severity varied. Ramsey, St George, 5C and 110R demonstrated relatively light PD symptoms, while Freedom, 3309C and O39-16 showed high PD scores. Significant variations of vine survival rate were observed in the 3rd growing season when Freedom, 3309C and O39-16 lost more than 50% of their original vines. In the mid-6th growing season, only four rootstocks had more than 70% vines alive, with 100% survival of Ramsey rootstocks. Vine vigor was evaluated from 2002 to 2005, and varied among the rootstocks when assessed by trunk diameter, annual shoot length, annual shoot node number, and shoot diameter. The overall growth performance suggested that Freedom, 3309C, 44-53M, 101-14MGT and 5BB could not endure the North Florida environmental conditions.
Jiang Lu, , Zhongbo Ren, and P. Cousins, (2008). EVALUATION OF GRAPE ROOTSTOCKS FOR RESISTANCE TO PIERCE'S DISEASE AND ADAPTATION TO NORTH FLORIDA ENVIRONMENT . Acta Hortic. 772, 257-261
Vitis vinifera, North American grapes, disease resistance