Early Acclimation Response in Grapes (VITIS)

Abstract

Acclimation in response to a decreasing daylength prior to the onset of low temperatures can be critical to the winter survival and productivity of many woody plants. This is particularly true for temperate fruit crops such as grapes. Grapes are native to the northern hemisphere, however they have a very large production range extending from the subtropics to 50 N and S latitude. Acclimation and freezing tolerance characteristics of this high value crop are very important as many production regions incur damaging freezes in fall, winter or spring. Typically production regions are recommended on the basis of the midwinter low temperatures; however, in many North American growing areas, injury during unseasonable low temperatures in the fall when the canes are maturing and acclimating can be as damaging as low midwinter temperatures (Bordelon et al., 1997, Clore et al., 1974, Seyedbagheri and Esmaeil, 1994). Therefore, a better understanding of the mechanisms involved in the onset of acclimation and freezing tolerance in grapes is needed to improve cultivar selection and cultural practices to minimize losses due to freezing injury.