ISHS Acta Horticulturae 493: I ISHS Workshop on Water Relations of Grapevines
RESPONSES TO DROUGHT OF BALANCE-PRUNED AND MINIMALLY-PRUNED 'CONCORD' GRAPEVINES |
| Authors: | Alan N. Lakso, R. M. Dunst, A. Fendinger |
| Keywords: | pruning, photosynthesis, fruit growth, light interception, yield |
| Abstract:
Historically, Concord (Vitis labruscana) native-American fresh juice grapes have not been irrigated when grown with standard heavy pruning in the cool, humid climate and soils of New York. The advent of minimal pruning of vines has led to more rapid canopy development and heavier crops that may need more water than conventionally-pruned vines. An experiment was established with minimal versus conventional pruning with and without supplemental drip irrigation. Differences in light interception were documented showing a much more rapid light interception by the minimally-pruned vines although by mid-season differences were small. In a very dry warm year comparisons were made of vine growth and leaf gas exchange responses over the season. The primary difference in response to drought was that the minimally-pruned vines used more soil water early in the season due to the higher early light interception and therefore depleted the soil water supply earlier than in the conventionally-pruned vines. This led to earlier reduction in leaf photosynthesis, reduced berry growth earlier during the cell division period and later and eventual partial defoliation in the drier sites. Numbers of live shoots the following year in the minimally-pruned vines was reduced as was the subsequent crop, while the subsequent crop of conventionally-pruned vines was only slightly reduced. | |
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