Wines & Vines

April 2012 Oak Alternatives Issue

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WineEast Pinot Gris vines were inspected after pruning in May 2009. Control vines considered critical to vinifera productivity and survival. this study was initiated to take advantage of that natural freezing event and address the lack of information about the above is- sue. the specific objective was to evaluate various pruning strategies of one vinifera va- riety that sustained extensive winter injury, Pinot Gris, and eventually to identify the best method of pruning to recommend to commercial growers. Pinot Gris vines trained to a bilateral cor- don system and typically spur pruned were exposed to vineyard temperatures of -15°f on Jan. 15, 2009, at the Oardc research vineyard in wooster, Ohio. four pruning treatments were applied in March: 1. Spur pruning (standard): consisted of retaining six nodes per foot of cordon; 2. two-node hedging: consisted of hedging canes to two-node spurs and retaining all spurs; 3. five-node hedging: consisted of hedging canes to five-node spurs and retaining all spurs; 4. no pruning. cane pruning was not included be- cause it already is known that vines per- form poorly when cane pruned following winter injury. winter injury also was mon- itored in august 2009 by further assess- ing the vascular tissue injury in cordons and trunks. at harvest, yield components data were collected. to determine carry- over effects of the 2009 winter injury, the study continued in 2010 to assess vine recovery after returning to normal pruning practices. Since no significant bud injury occurred during the second year, all vines from all treatments were pruned similarly and back to the standard spur pruning (six nodes per foot of cordon.) Pruning duration and Wines & Vines APRiL 2012 61 weren't pruned. Also pictured: five-bud weight of 1- and 2-year-old wood were determined. Pruning weights of 1-year-old wood (i.e., canes) were used to determine the ravaz index (ri) as the ratio of crop- to-cane pruning weight. the numbers of count buds and clusters per vine were re- corded in 2010 to assess whether pruning treatments affected bud fruitfulness (ratio of clusters to count buds.) The results in May 2009, the no-pruning treatment resulted in the earliest and most vigorous growth, whereas spur pruning had the latest and weakest; hedge pruned were and two-bud hedging. Vance_Jan11.qxp 11/23/10 9:29 AM Page 1 intermediate (see photos above), resem- bling early canopy development observed in minimally pruned vines. in July and august 2009, we also observed the so called "mid-summer vine collapse," which took place pre-veraison through post-veraison and consisted of leaf wilt- ing and shoot collapse in a portion of the cordon (partial collapse) or whole vine (total collapse.) (See photos on page 64.) it is an indicator of vascular damage including phloem, xylem and even cam- bium tissues. the assessment of cordon, trunk and whole vine injuries confirmed vascular damage and that cordons, trunks ( c en t er ) ( l e f t)

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