Evaluation of Vitis vinifera and Vitis interspecific hybrid grape cultivars for resistance to Botrytis and sour bunch rots in Biglerville,PA,2011.

摘要

Ten Vitis vinifera and four Vitis interspecific hybrid grapes were evaluated for resistance to Botrytis bunch rot and sour rots at the Penn State Fruit Research & Extension Center, Biglerville, PA. Vinifera grapes were trained in vertical shoot positioning (VSP) and interspecific hybrid vines were top wire-trained, except for Vidal, which was trained VSP. Vines planted in 2008 were spaced 6 x 9 ft. and arranged in a randomized complete block design with six replications, and 4 vines per plot. The vineyard received a maintenance fungicide program applied at 7-14 day intervals to control seasonal grape diseases. The vineyard also received a maintenance insecticide program throughout the growing season using an air-blast sprayer (100 gal/A at 400 psi).The susceptibility of the different cultivars to bunch rots was evaluated at harvest. Rainfall for Apr, May, Jun, Jul, Aug and Sep was 11.35 in., 4.32 in., 1.42 in., 3.86 in., 4.21 in. and 16.05 in., respectively. High temperature and frequent rain in the weeks before and during harvest favored severe sour rot infection in the vineyard. The incidence of Botrytis and sour rots was rated on fruit clusters by visually determining the percent clusters infected on 40 arbitrarily-selected clusters per cultivar-plot. Severity (percent infection within a cluster) was rated using the Barratt-Horsfall scale and was converted to percent area infected using Elanco conversion tables. Data were analyzed using analysis of variance and mean separation was determinedby the Fisher's Protected LSD test (P < 0.05) (SAS Institute Inc., Cary, NC).