RT Journal Article
SR Electronic
T1 Evaluation of Primary Bud Freezing Tolerance of Twenty-three Winegrape Cultivars New to Eastern U.S.
JF American Journal of Enology and Viticulture
JO Am. J. Enol. Vitic.
FD American Society for Enology and Viticulture
SP ajev.2015.15047
DO 10.5344/ajev.2015.15047
A1 Imed E. Dami
A1 Shouxin Li
A1 Yi Zhang
YR 2016
UL http://www.ajevonline.org/content/early/2015/12/23/ajev.2015.15047.abstract
AB Plantings of Vitis vinifera (vinifera) cultivars have increased significantly in Eastern U.S. due to market demand for their wines. However, vinifera is a cold sensitive species and planting new cultivars with unknown cold susceptibility in cold areas has resulted in frequent winter damage and crop loss in recent years. It is the purpose of this study to determine the freezing tolerance of 23 winegrape cultivars predominantly grown in Europe and South Africa and to compare three statistical methods [mode-date, piecewise regression and annual mean LT50 (AFT)] for determining the minimum low temperature that will kill 50% of primary buds (LT50). Primary bud FT, expressed as LT50 in °C, was determined biweekly over three dormant seasons under field conditions in the state of Ohio, U.S.A. Minimum LT50 was most accurately determined using the AFT method. AFT had a lower error estimate than mode-date or piecewise regression and best corresponded with the percent vines that survived exposure to the polar vortex freeze events of 2014 (R2=0.38). The 2-year average AFT ranged from −19°C for Gamay noir to −15°C for Barbera and distinguished a 1°C difference among cultivars in primary bud FT. We have also proposed to express cultivar AFT relative to a standard cultivar grown in the same location (Merlot in this study), termed RAFT. The results from this study can be used to assist selection of vinifera cultivars suitable for vineyard sites where freezing temperatures limit wine grape production.