- - AGRICULTURE CORE CURRICULUM - - (CLF7000) Advanced Core Area: PLANT AND SOIL SCIENCE (CLF7600) Unit Title: PRUNING ____________________________________________________________________________ (CLF7608) Topic: PRUNING Time Taught in Year(s) GRAPEVINES 2 hours 3 and 4 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson the student will be able to: Learning Outcome #: (K-6) - Identify 3 common training systems (head, cordon, cane) that are currently used in Calif., and name a variety trained to each system. (K-7) - Demonstrate a grapevine pruning technique in class. (K-8) - Using specific terms, identify the external parts of a grapevine. (K-9) - Define the following terms related to grapevine pruning head, cordon, cane, renewal spur, replacement spur and spur. Special Materials and Equipment: Appropriate tools and vines for practice and picture of pruned vines using the various systems. References: U.C. Publications for Vineyard Management Evaluation: Quiz by instructor TOPIC PRESENTATION: PRUNING GRAPEVINES A. The success of a vineyard may depend to a large extent on the pruning practices used. The styles of pruning used on grapevines in California are grouped into three systems namely head, cordon, and cane. B. In the head system the mature vine has a vertical trunk 1 to 3 feet high. 1. It bears at its top, a ring of arms or short branches. 2. Each winter pruning spurs are left at the ends of these arms to produce shoots that will bear next years crop and furnish canes for next year's spurs. 3. This system consists of head training and spur pruning. 4. There are several advantages of head pruning: a. simplicity of form, b. ease of training, c. cheapness of establishment, and d. cross cultivation is possible. 5. The disadvantages of this system include a depressing effect of such severe pruning and the massing of fruit in a small area. 6. Head pruning suits most varieties that bear well on short spurs. It is used for wine grapes and some table grapes. (Varieties so pruned include Alicante, Grunache, Mission, Muscat and Zinfandel.) C. Cordon pruned vines have no definite head. 1. The trunk, which is much elongated either vertically or horizontally, has arms at intervals of 8 to 12 inches over the greater part of its length. a. In California only the horizontal bilateral form is recommended. b. The trunk rises vertically to a point about 8 inches below the supporting wire of a tellis. 1) Here the trunk is divided into two equal branches (cordons) rising to the wire in a gentle bend and extending in opposite directions. 2) Each cordon comes to within 8 to 12 inches of the cordon from the adjacent vine. c. The bearing units are spurs on short arms located at regular intervals on the horizontal part of the cordons. d. These spurs should, whenever possible , extend in an upward direction. 2. Advantages to the cordon system are: a. fruit is well distributed horizontally across the vine, b. all clusters hang about the same distance from the ground (favorable to uniform development and maturation of fruit). 3. Disadvantages are: more laborious job to train and establish, more expensive to establish, and employees must be more skilled. 4. In California, cordon pruning is well adapted for table grape varieties, particularly Cardinal, Emperor, Malaga, Ribier and Tokay. D. In cane pruning, the vine is given a trunk similar in form to that in head pruning. 1. This head differs in that it is fan-shaped in the plane of the trellis. a. Only two arms on each side of the head are usually needed. b. The bottom two are at the level of a lower wire of the trellis, the top two at the level (or below) the upper wire. 2. At each annual pruning of a mature vine fruit canes containing 8 to 15 buds (2 to 5 ft in length) are retained for producing the crop. a. The old fruit canes are removed each year. b. The production of canes for use the following year is left largely to renewal spurs. c. These renewal spurs are usually 2 buds long and located near the base of each fruit cane. 3. Cane pruning is necessary for varieties such as Thompson Seedless that have mostly unfruitful buds near the base of the canes. Other varieties include Black Monukka, Perlette, White Riesling, Sauvignon blanc and some Pinots. 4. Several advantages are apparent for the cane pruning system. a. The fruit is distributed over a large area. b. There is a reduction in shot (small seedless) berries for varieties so inclined. 5. The disadvantages are two-fold. a. There is a tendency for most varieties to overbear. b. There is a high cost of trellising and annual pruning. E. The following are terms and definitions used in discussing grapevine pruning. 1. Head pruning is a pruning system where the mature vine has a 1 to 3 foot verticle trunk bearing a ring of arms, each ending in a spur. 2. Cordon pruning (bilateral) is a pruning system that has a vertical trunk that branches into two horizontal arms (cordons). Spurs are left at intervals along these cordons. 3. Cane pruning is a pruning system using a trunk with fan shaped arms trained in the plane of the trellis. Canes are left to produce the crop. 4. Renewal spurs are spurs left on the vine at the annual pruning that are used to grow (renew) the canes for the next years fruit production. 5. A replacement spur is a spur left by the pruner to replace an arm that is broken or being removed because of insect or disease problems. 6. A spur is the basal portion of a cane left to produce shoots and fruit for the next season (usually 1 to 4 buds in length). __________________________________________________________ ACTIVITY: 1. Show the students photos of the various pruning systems on vines that are dormant and on vines that are covered with foilage. 2. Demonstrate each of the three pruning systems to the students (cane, cordon, and head). 3. Have the students prune vines using each of the systems. 4. Have each student select the "best" vine that they have pruned explaining its merits. (shape, size, vigor, symmetry, framework, freedom from insects and diseases). __________________________________________________________ 7/25/90 sg #%&C