GRAPE BUD SURVIVAL IN THE MIDWEST FOLLOWING THE WINTER OF 1993-1994

The winter of 1993-1994 was one of the coldest on record across much o f the midwestern U.S. Minimum winter temperatures in January 1994 rang ed from -16 degrees F (-27 degrees C) to -39 degrees F (-39 degrees C) across Michigan, Indiana, and Ohio. Temperatures remained below 0 deg rees F (-18 degrees C) in most areas for several days during January p receding the coldest temperature events. Primary bud survival was rate d on 69 American, French-American hybrid, and Vitis vinifera grape cul tivars and advanced breeding selections in research blocks and commerc ial vineyards in Indiana, Michigan, and Ohio. Results generally are in agreement with previous reports in that American cultivars were the m ort hardy, French-American hybrids were somewhat less hardy, and the V itis vinifera cultivars were the-least hardy. However, some French-Ame rican hybrids including 'Foch', 'DeChaunac', 'Frontenac', 'LaCrosse', and 'Ventura' were more hardy than the American cultivars. Many cultiv ars had better bud survival than expected for the minimum temperatures experienced. These ratings represent a good measure of the maximum wi nter hardiness of the cultivars surveyed because conditions for winter hardening in the fan of 1993 were ideal, and there were no winter tem perature fluctuations or sharp temperature drops leading to the Januar y 1994 episode.