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54 practical winery & vineyard February 2015 G R A P E G R O W I N G P runing is one of the most impor- tant aspects of vineyard manage- ment, and selecting the optimum cane can be difficult. Although the influence of pruning techniques and training systems on vine growth and yield is well documented, 3,4 little is known regarding the influence of cane diameter on yield and gross profit. Increasing fruit production within a vineyard and improving yield predic- tions can keep grapegrowing competi- tive and cost-effective compared to other crops, which compete for land use. As the demand for wine increases world- wide, and the price of land increases, obtaining the most from a vineyard may be a more viable option than purchasing additional land. Improving yield predictions pro- vides the required information to make informed decisions regarding harvest logistics, potential financial gains, stor- age space, equipment usage and match- ing market demand. Our study investigates the influence of cane diameter on inflorescence archi- tecture, yield and the subsequent gain or loss in gross profit. Methods Sauvignon Blanc vines grafted on SO4 rootstock, in a commercial vineyard Mark Eltom,* Chris S. Winefield and Mike C.T. Trought *Department of Wine, Food & Molecular Biosciences, Lincoln University, New Zealand BY PRUNING OF SAUVIGNON BLANC VINES Influence of cane diameter on gross profit Three-cane Sauvignon Blanc vine in Marlborough, New Zealand. in Marlborough, New Zealand (41.53° latitude, 173.88° longitude), were used for the study. Vine rows were planted in a north-south orientation with 1.8 meters between the vines and 2.4 meters between vine rows. The training systems were established on whole vine rows (approximately 120 meters long), ran- domly distributed within four replicate blocks. Four vine rows per training sys- tem were used for this study. Vines were pruned during the winter as follows: 1) a bilateral-trained cordon spur-pruned to retain two nodes per spur and 10 spurs per vine; 2) head- The influence of cane diameter on yield was examined in two growing seasons. Inflorescence number per shoot along a cane increased as the diameter of the cane increased, resulting in a change in gross profit in the range of approxi- mately +/- 15%. Therefore, yield can be signifi- cantly modified as early as pruning. trained four-cane, 10 nodes per cane (40 nodes per vine); and 3) head-trained two- cane (20 nodes per vine). Two foliage wires kept shoots in a ver- tical position, and vines were trimmed two or three times during the season, at a height of 2.0 meters above ground and 0.5 meters between the vertical faces of the canopy. Leaf removal was performed approximately three weeks after fruit set on both sides of the canopy to achieve approximately 30% to 40% bunch expo- sure. Twelve, six and three vines per vine row were selected within each of the vine rows at random for the spur, two-cane and four-cane pruning systems respectively. Gross profit per vine was calculated according to equation 1 (below). Average inflorescence number per cane was cal- culated from the relationship of cane diameter versus inflorescence number per cane. Equation 1. Gross profit per vine = (number of canes per vine) X (average inflorescence number per cane) X (aver- age berry number per inflorescence) X (average berry weight) X (grape price). Renewal spur 59 Barrel alternatives supply oxygen to wines during élevage by Alexandre Pons, Andrei Prida, Benoit Verdier, Philippe Darriet and Denis Dubourdieu 67 Carboxymethyl Cellulose – CMC: Non-subtractive approach to potassium tartrate stabilization by Peter Salamone and Anita Oberholster T E C H N I C A L R E S O U R C E F O R G R O W E R S & W I N E R I E S Don Neel, Editor practicalwinerylibrary.com Access Practical Winery & Vineyard article archives online.