Department of Horticultural Sciences, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, 14456, USA

Breeding for pest resistance has been a long-standing goal of grape breeders. Although some hybrids and "native varieties" have varying degrees of pest resistance, most still require a regular pesticide applications to maintain crop quality and vine health. By contrast, wild vines growing under natural conditions often appear to be virtually free of pests and disease (though fruit quality is low). Our goal is to identify and then utilize germplasm of the highest level of pest resistance under "no-spray" conditions for the development of new cultivars.

Vines were established in 1991, and have had no fungicide or insecticide applications. Standard varieties have been included throughout the planting to assess the uniformity of disease severity. The vineyard is split into two blocks: a second test block to evaluate selections and species, and a seedling block. Observations include: trunk injury, vine vigor, and crop load, as well as disease ratings of leaves and fruit.

Disease severity and timing of infection have varied between years, but disease pressure has always been high and genotypic differences consistent. Some selections have been too disease susceptible for long-term survival, while others have been healthy and vigorous. Some vigorous and fruitful vines occasionally showed a large percentage of leaf surface infected with powdery mildew. Vines judged to be highly resistant, and having reasonable fruit quality, have been paired with other "quality" parents in crosses for future evaluation and selection. Some of the top selections for disease resistance include: Ill. 547-1 (V. rupestris x V. cinerea), NY66.795.01 ((BS 2667 x V. cinerea) x Dunst. 200), BR14 (V. rupestris x Seibel 14), and NY65.550.04 ((Jaeger 70 x Victoria's Choice) x SV 23-18 op).