ISHS Acta Horticulturae 689: VII International Symposium on Grapevine Physiology and Biotechnology
INFLUENCE OF CROP LOAD ON ´CHAMBOURCIN´ YIELD, FRUIT QUALITY, AND WINTER HARDINESS UNDER MIDWESTERN UNITED STATES ENVIRONMENTAL CONDITIONS |
| Authors: | I. Dami, D.C. Ferree, S.K. Kurtural, B.H. Taylor |
| Keywords: | crop level, cluster thinning, cold hardiness, photosynthesis, ripened nodes |
| Abstract:
The effects of various crop levels on vegetative growth, yield components, fruit composition and winter hardiness of ‘Chambourcin’ grapevines were evaluated in Illinois and Ohio for two and four years, respectively. In the Illinois study, treatments consisted of three pruning levels (15, 20 and 25 nodes retained for each 0.454 kg of dormant prunings) and three cluster-thinning levels (1, 2 and 2+ clusters (no thinning) per shoot in year one and 1, 1.2 and 1.5 clusters per shoot in year two). Treatments consisted of three cluster-thinning levels of 10, 20, and 30 clusters retained per vine in Ohio. As the number of clusters retained per vine increased, yield increased. Total soluble solids and pH of the grape juice decreased as the number of clusters retained per vine increased. As the number of clusters retained per vine increased, the number of ripened nodes and bud cold hardiness (measured as LT50) decreased. There was little interaction between pruning and cluster thinning treatments in both years of the study in Illinois. ‘Chambourcin’ grapevines were most affected by cluster thinning treatments in both states. Crop load varied with vineyard geographical location. It was concluded that ‘Chambourcin’ grapevines grown at a wider spacing and longer growing season in southern Illinois had higher crop load ratios (10 to 14) than those grown at a narrower spacing and shorter growing season in northeast Ohio (4 to 8). | |
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