First Paragraph: The cultivars 'Tokay,' 'Carignane,' 'Zinfandel,' 'Chenin blanc,' and 'Grenache' were used in shoot break-out experiments in seven vineyards in San Joaquin County. A total of 45 single-vine plots were used in a completely randomized block within each vineyard. The shoots were I to 8 inches long at the time that some had been injured by frost. In each trial the shoots on 15 vines were broken out by hand and on a second group only frostdamaged shoots were removed. All shoots on control vines were left untouched. At harvest, clusters were separated into classes depending on the origin of the supporting shoots. Analyses of variance revealed no significant increases in yields due to either treatment.