Issue link: http://winesandvines.uberflip.com/i/766392
Janaury 2017 WINES&VINES 167 WINE EAST GRAPEGROWING Basic Hoe comes with a Hillup and a Takeaway Blade. Additional attachments include .3 Tooth Cultivator, Undercutter Blade, Rotary head, " NEW " Rolling Cultivator and "Vine Auger". The Green Hoe Company, Inc. 6645 West Main Road, Portland, NY 14769 PHONE (716) 792-9433 FAX (716) 792-9434 WWW.GREENHOECOMPANY.COM GREEN GRAPE HOE critical temperature of -20° C (-4° F) five times (-20.1° C [-4.2° F] to -24.5° C [-12.1° F]). All 23 varieties sustained trunk damage, with the exception of Regent. The extent of whole-vine damage was assessed in late summer 2014, and vine death was recorded. In general, variety vine mortality corre- sponded to the computed LT 50 . For example, Tempranillo, with the highest LT 50 (most cold sensitive), sustained the highest vine mortal- ity (100%), while Gamay Noir, with the lowest LT 50 (most cold hardy), sustained the least vine mortality (17%). Therefore, the 2014 winter damage sustained in the vineyard co- incidently confirmed our cold hardiness de- termination in the laboratory. Modified standard method: This method based on regression analysis was explored to alleviate the limitation of the standard method. It proved superior to the standard method since it distinguished the CH between two varieties at 2° C (3.6° F). However, it was not possible to obtain estimates for all varieties tested since more LT 50 observations were needed. A new index–the AFT: The annual freezing tolerance (AFT) or annual cold hardiness con- sisted of averaging LT 50 throughout the dor- mant season. AFT has several advantages over the standard method currently used by nurser- ies, growers and researchers. First, AFT pro- vides an estimate of CH across all stages of cold acclimation (i.e., autumn acclimation, mid- winter maximum hardiness and spring deac- climation). As a result, the AFT had the least LT 50 variability, and differences between two varieties were detected at the 1° C (~ 2° F) level (see "Annual Freezing Tolerance for Cal- culating Cold Hardiness"). Second, the stan- dard method provides an LT 50 of a given variety determined on a specific date and location. Hence, this absolute value provides an arbi- trary measure of CH, which will vary with time and space. In other words, one cannot extrapo- late LT 50 published values determined in one location (e.g., in New York) to equate the ac- tual LT 50 in another region (e.g., in Missouri). This may be common knowledge within the research community, but it is frequently misin- terpreted by vineyard owners and nurseries. To overcome this issue, we propose to com- pare the CH of varieties to a standard or bench- mark variety grown in the same location. We call the new index the relative annual freezing tolerance, or RAFT. Merlot was selected since it is a common variety grown in different re- gions worldwide and has mid-range CH. The figure above illustrates RAFT with nega- tive numbers indicating more cold-hardy varieties and positive numbers more cold-sensitive variet- ies than Merlot. For example, Gamay has a RAFT of -2.5° C, meaning Gamay is more hardy than Merlot by ~2.5° C. However, Barbera has a RAFT of ~1.5° C, meaning Barbera is less cold hardy than Merlot. In other words, if a region is known to have Merlot as a borderline variety for winter survival, then a grower should not even think about planting Barbera in the same region. Finally, among the three methods, AFT pro- duced the best prediction of whole-vine CH. Imed Dami is professor of viticulture in the Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, in Wooster, Ohio. The author thanks project participants Dr. Yi Zhang and Shouxin Li and the USDA-NIFA (agreement No. 2010- 51181-21599), Ohio Grape Industries Program and OSU Department of Horticulture and Crop Science for their financial support. RELATIVE ANNUAL FREEZING TOLERANCE RAFT (˚C) 3 2 1 0 -1 -2 -3 Cultivar Annual cold hardiness is shown relative to that of Merlot, computed by subtracting the annual mean LT 50 of each variety from that of Merlot (baseline 0º C). Gamay Noir Pinotage Rotberger Chardonnay Malvasi Regent Siegerrebe Carmenère Cabernet Sauvignon Sauvignon Blanc Cabernet Franc Malbec Arneis Merlot Kerner Teroldego Sangiovese Syrah Lagrein Tempranillo Durif Barbera Dolcetto EASTERN WINE LABS Serving the Analytical needs of East Coast Wineries WWW.EASTERNWINELABS.COM Ph 609-859-4302 Cell 609-668-2854 chemist@easternwinelabs.com AOAC Member EasternWineLab_Mar09.qxp 1/22/09 9:47 AM Page 1