Research: Cold Hardiness
Basinger, A. R., and E.W. Hellman (2007). “Evaluation of Regulated Deficit Irrigation on Grape in Texas and Implications for Acclimation and Cold Hardiness.” International Journal of Fruit Science 6(2): 3-22.
Deficit irrigation is used increasingly as a vigor management tool and to conserve water in grape vineyards. Several strategies including regulated deficit irrigation (RDI) have emerged, but none has been evaluated in Texas. Deficit irrigation has also been observed to influence vine acclimation and presumably vine cold hardiness. Experiments were established in a commercial ‘Cabernet Sauvignon’ (Vitis vinifera) vineyard in west Texas to evaluate RDI under local conditions and to study the potential for deficit irrigation to induce earlier shoot acclimation and influence cold hardiness. RDI significantly reduced pruning weights by as much as 46% and increased applied water-use efficiency up to 72%, but had little or no effect on yield components or fruit composition, indicating that these strategies could be useful in west Texas. Deficit irrigation was consistently associated with earlier and more rapid development of periderm on shoots, but had no effect on bud cold hardiness.
Fennell, A. (2004). “Freezing Tolerance and Injury in Grapevines.” Journal of Crop Improvement 10(1-2): 201-235.
Grapes, due to their wide distribution, are one of the temperate fruit crops most frequently damaged by freezing temperatures. Freezing injury can result in decreases in yield and substantial economic losses to grape growers, subsequently impacting fruit wholesalers, wineries, distributors, and related industries. Freeze damage is not limited to the northern or southern limits of the production range. Freezing injury can occur in spring, fall, or winter in many of the grape growing regions. An understanding of the mechanisms involved in freezing tolerance, acclimation, and deacclimation in grapevines is needed to match cultivars appropriately with growing sites, improve cultural practices that minimize freezing injury, and aid in breeding and selecting cultivars with improved freezing tolerance. The ability to avoid or tolerate freezing temperatures includes a complex set of traits that is influenced by the inherent genetic characteristics of the grapevine and its interaction with the environment. In the present review, the mechanisms of freezing tolerance in grapevines are summarized and discussed in relation to the influence of genotype, phenological development, and environmental factors.
Hamman, R. A. J., I.-E. Dami, T.M. Walsh, and C. Stushnoff (1996). “Seasonal Carbohydrate Changes and Cold Hardiness of Chardonnay and Riesling Grapevines.” Am. J. Enol. Vitic 47(1): 31-36.
Cold hardiness and endogenous levels of soluble sugars were monitored during the dormant season for Chardonnay and Riesling (Vitis vinifera L.) dormant buds and stem cortical tissues. Endogenous levels of glucose, fructose, raffinose, and stachyose were strongly associated with cold hardening, increasing from the onset of cold acclimation in August to maximum cold hardiness in December and January. During dehardening in March and April, endogenous levels of these sugars dropped as temperature increased. A high ratio of glucose and fructose to sucrose coincided with maximum cold hardiness, and a low ratio was associated with the dehardened condition in fall and spring. Sucrose levels, however, were not associated with cold hardiness in either cultivar. Neither cold hardiness nor soluble sugars of grape tissues were influenced by a late harvest compared to harvest at normal fruit maturity.
Mills, L. J., J.C. Ferguson and M. Keller (2006). “Cold-Hardiness Evaluation of Grapevine Buds and Cane Tissues.” Am. J. Enol. Vitic 57(2): 194-200.
A system for differential thermal analysis (DTA) was constructed to assess cold hardiness of grapevine buds and cane tissues. This updated system incorporated a sample chamber of our own design with a commercially available programmable freezer and data acquisition system (DAS). Thermoelectric modules (TEM) were used to sense exotherms that are produced when water or tissues freeze. The TEM signals recorded by the DAS at 15 sec intervals were downloaded directly to an Excel spreadsheet. The DTA system was designed to test up to 35 samples of five buds or three canes per TEM simultaneously. Bud and cane low temperature exotherms (LTE) recorded by this system correlated very closely with those of a standard system, and the extent of cane phloem and xylem injury, based on tissue browning, corresponded well with expected injury based on LTE analysis. The LTEs of moist buds were 3°C to 4°C higher and those of moist canes 2°C higher than LTEs of corresponding dry tissues, indicating that surface moisture increases the susceptibility to cold injury. Cold hardiness of eight grape cultivars increased from late fall through mid-January, after which buds and canes began to deacclimate. Riesling was the hardiest of all cultivars tested. Chardonnay reached similar levels in midwinter, but was considerably less hardy in late fall and late winter. Pinot gris and Viognier were the least hardy among the white winegrape cultivars. Among red winegrape cultivars, Cabernet Sauvignon was generally the hardiest and Merlot the least hardy, with Malbec and Syrah being intermediate.
Smallwood, M. a. D. J. B. (2002). “Coping with the Cold: The Molecular and Structural Biology of Cold Stress Survivors.” Philosophical Transactions: Biological Sciences 357(1423): 831-847.