Effects of Timing and Severity of Summer Hedging on Growth, Yield, Fruit Composition, and Canopy Characteristics of de Chaunac. II. Yield and Fruit Composition

¹ Agriculture Canada Research Station, Summerland, B.C. V0H 1Z0, Canada.

Ten-year-old Geneva double curtain trained de Chaunac vines were hedged at one of three times (postbloom, full canopy development, and veraison) and to one of three severities (retaining five, 10, or 15 leaves per shoot) combined in a 3 x 3 factorial treatment arrangement along with an unhedged control. Yield was not influenced by treatments in 1985, but was reduced linearly by increased hedging severity in 1986 and 1987 and to some degree by delaying hedging. Clusters per vine were affected least by 10-leaf and postbloom hedging. Cluster weight and berries per cluster were reduced linearly by increasing severity of hedging. Berry weight was highest in vines least-severely hedged at full canopy development. Soluble solids (°Brix) and total anthocyanins were reduced proportional to severity of hedging in 1985 and 1987, but this trend was reversed in 1986. Both °Brix and anthocyanins decreased linearly with delays in hedging in 1985. Titratable acidity tended to decrease with delayed hedging and when hedging became less severe. Increases in pH in 1985 were associated with decreased hedging severity and delayed hedging. Control vines tended to be equal to, if not superior to, all hedging treatments in terms of many yield and fruit composition parameters. In general, all significant undesirable yield and fruit composition responses were found in treatments involving the five-leaf severity and the full canopy and veraison timings.

Key words: canopy management, hedging, de Chaunac

Submitted on September 6, 1988