1a.Objectives (from AD-416):
The objective of this cooperative research project is to conduct collaborative
viticulture research of mutual benefit to ARS and the University of Idaho. The
research conducted by the University of Idaho will be complementary to the wine
grape research program established by ARS at the University of Idaho’s Parma
Research and Extension Center. The broad objective of the ARS program is to
investigate integrated, sustainable production practices for development of improved vineyard management strategies and improved end product quality or perceived market
1b.Approach (from AD-416):
Investigate critical management and production practices impacting wine grape
quality components. Emphasis will be placed on water and canopy management, endproduct processing methods, as well as germplasm evaluation.
This research was conducted in support of NP305 objective 1 "Determine effects of water management on wine grape productivity and fruit maturity" of the parent project. Establishment of vines according to quadrilateral cordon improved cluster and berry quality in all cultivars. Emerald, Alborz, and Jupiter had much “cleaner” berries without any blemish when grown under quadrilateral cordon as compared to bilateral cordon. That is due to that fact that clusters hang freely, without being tangled between wires in quadrilateral cordon. Cluster shortening did not significantly improve berry size in Jupiter while it improved berry size in Alborz. Yield of Alborz with quadrilateral cordon was almost twice as much as that of bilateral cordon while fruit quality was the same. Cluster removal and cluster cutting with and without girdling were practiced in ‘Alborz’ and ‘Emerald’ and Jupiter. Alborz vines that received cluster shortening and cluster removal plus girdling had significantly larger berries than control vines. Alborz vines that received no treatment (control) as well as those with cluster removal but not shortened had significantly longer clusters than all other treatments. Vine acclimation and hardening under divided canopy systems was much faster than that under bilateral cordon in all tested cultivars.
Our results indicated that new cultivars such as ‘Kashishi’, and ‘Autumn Royal’ and ‘Jupiter’ may have a great potential and we intend to continue our research on these cultivars. However, ‘Anahita’ and ‘Kashishi’ were sensitive to spring cold and productivity could be diminished as a result of cold springs. Overall, three applications of gibberrelic acid, each at 50 ppm, starting at fruit set within a 5-day interval showed satisfactory results and produced berries at sizes 12-14 (based on California sizing system). Effects of regular storage on fruit quality and berry storability were studied in certain cultivars including ‘Alborz’, ‘Jupiter’, ‘Bidaneh’ and ‘Red Globe’. ‘Red Globe’ and ‘Bidaneh’ had the longest storage life and with the use of sulfur pads, they could be stored until late November and some until late December. Performance of different cultivars under storage conditions will be further studied.