Texas Viticulture Research
Ongoing Projects
For additional information on the Texas Viticulture Research Program contact members of the team:
Ed Hellman
Thayne Montague
Jim Kamas
Pierce's Disease
Pierce's disease in Texas is being addressed by a multidisciplinary interagency program that combines the research and Extension education expertise of numerous scientists. Research reports are posted on the program website:
Texas Pierce's Disease Research and Education Program
Physiology of Grape Variety Adaptation to Climate
A research vineyard was established in 2006 to study the physiological basis of grapevine adaptation to climate – what makes a variety well-adapted to a hot climate? Twenty grape varieties have been planted representing a range of varieties that are known to perform well in different climatic regions (hot, warm, cool). The trial was established in a randomized, replicated experimental vineyard at the Texas A&M Agricultural Research and Extension Center in Lubbock. Each variety is represented by 4 replications of 5-vine plots in a randomized complete block design.
Preliminary grapevine physiology data has been collected from young vines. Vine physiology parameters measured are: leaf water potential, stomatal conductance, transpiration, and photosynthesis. Weather data is being collected on-site with an automated weather station to enable study of relationships between grapevine physiology and climatic variables.
Wine Grape Variety Evaluations
Texas is participating in the national program NE-1020: Multi-state Evaluation of Wine Grape Cultivars and Clones. This program employs coordinated regional trials using a standardized experimental design and data collection protocol, and includes production of experimental wines. Two "standard" varieties are included in each trial to enable comparison of results from different testing locations. The Texas variety trial includes eight varieties that show good promise for hot climates. The trial will be established in 2008 at the Texas A&M Agricultural Research and Extension Center in Lubbock. Varieties included in the trial are listed in the table below.
| Texas NE-1020 Variety Trial |
| Aglianico | Negro Amaro |
| Cabernet Sauvignon* | Roussanne |
| Carignane | Souzao |
| Malvasia bianca | Touriga nacional |
| Merlot* | Verdejo |
| *Standard variety for comparison |
Rootstock Evaluations
A preliminary rootstock evaluation trial has been established at the Texas A&M Agricultural Research and Extension Center in Lubbock. The trial includes Merlot grafted to five rootstocks: 110R, 1103P, 44-53, 5BB, and Freedom. Grenache is being compared on three rootstocks: 110R, 1103P, and Freedom. A large rootstock evaluation trial is being planned for establishment in 2009 or 2010. It will include 6 rootstocks currently in common use and 6 new rootstock varieties developed in California for resistance to root-knot nematode. Rootstocks will be evaluated for effect on the viticultural characteristics of the scion variety. Parameters to be measured include pruning weight, yield and yield components, fruit composition, and phenology dates.
Recently Completed Projects
Evaluation of Regulated Deficit Irrigation in Texas
Basinger, A.R. and E.W. Hellman. 2006. 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.
ABSTRACT. 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.
Evaluation of Abscisic Acid to Delay bud break of grapevines
Hellman, E.W., S. Shelby, and C. Lowery. 2006. Exogenously applied abscisic acid did not consistently delay budburst of deacclimating grapevine.Journal of the American Pomological Society 60:178-186.
ABSTRACT. An experimental formulation of abscisic acid (ABA; Valent Biosciences VBC-30025) was evaluated for potential to delay budburst of (Vitis vinifera L. winegrapes. Five experiments were conducted during 2004 and 2005 on dormant grapevine cuttings, container-grown vines, and field-grown vines to evaluate rates and/or timing of ABA applications. Two application methods were tested - spray application to buds or soil application. Spray application of ABA solutions to unopened buds increased the number of days to budburst by 3.5 days in one of four laboratory trials on single-bud cuttings, and delayed budburst by one day in established field-grown vines in one of two years. Further study to enhance the efficacy of ABA spray applications should examine materials or methods to improve penetration of ABA through bud scales. Soil applications of ABA to container-grown vines provided the greatest delay in budburst (up to 7 days) and gave the most consistent response. Soil application of ABA to established field-grown vines, however, produced no response and this may not be a practical or economical application method for commercial vineyards.
Archive of Viticulture Research Reports
Grape Cultivar Performance on the Texas South Plains, 1974-1986
