Progress 07/01/03 to 06/30/05
Outputs
A vineyard field trial was established on a WSU-IAREC site with three Vitis vinifera scion cultivars on six different Vitis rootstocks or their own roots. At the end of the 2004 growing season scion establishment was 90% for Merlot, 91% for Syrah, and 87% for Chardonnay. Growth, yield formation and fruit development were monitored during the 2004 growing season. Results indicated a pronounced cultivar effect (Syrah suffered considerable winter freeze damage due to insufficient cold acclimation) but few differences among rootstocks. Nevertheless, two rootstocks (110R and 140-2) performed poorly and were found to reduce scion capacity (growth and yield). This was mainly due to their poor tolerance of cold winter temperatures. Soluble solids were highest when yields were between 6.5-9 lbs/vine and decreased slightly when crop levels exceeded 9 lbs/vine. Overall, the results suggested that 110R and 140-2 are probably not among the preferred rootstocks choices for
Washington, and that establishment of field-grafted Syrah is considerably more difficult than Merlot or Chardonnay.
Impacts
Results suggested that 110R and 140-2 are probably not among the preferred rootstocks choices for Washington, and that establishment of field-grafted Syrah is considerably more difficult than Merlot or Chardonnay. Valuable knowledge was gained on the feasibility of field grafting and the performance of Vitis rootstocks under severe Washington winter conditions. As a result of this research growers have already begun to use field-grafting as a tool to change cultivars quickly and cheaply (i.e. without the need to remove and replant entire vineyards). This enables them to adapt to changing market demands much more rapidly than was previously thought possible.
Publications
- No publications reported this period
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Progress 01/01/03 to 12/31/03
Outputs
A rootstock field trial with Chardonnay, Merlot, and Syrah on their own roots or the rootstocks Teleki 5C, MGT 101-14, Couderc 3309, Ruggeri 140-2, Richter 110, and 1103 Paulsen was planted at WSU-Prosser in 1999 and 2000, and field-grafted in 2002 and 2003. Each combination is replicated ten times with seven vines per replicate. The rootstocks were field-grafted in early July of 2002 using the chip-budding technique; one shoot of each rootstock was grafted at 10 in. and another one at 27 in. above the ground. Despite the extensive cold damage due to the Halloween freeze of October 2002, we gained valuable information on scion/rootstock performance under Washington conditions. Field grafting of the WSU-IAREC rootstock trial in 2002 had a success (take) rate of 96% for Chardonnay, 94% for Merlot, and 89% for Syrah, but there were no differences among rootstocks. There was also a significant (p less than 0.001) effect of grafting height: grafting 10 in. above the ground
led to 91% take, whereas grafting at 27 in. had more than 99% take, possibly due to ease of grafting and avoidance of damage from weed control at the higher position. However, the severe fall frost (12F) before plants were fully cold acclimated led to considerable loss of scions. Budbreak in spring of 2003 was very irregular, but once a scion shoot was growing, vine collapse later in the season was extremely rare. Graft survival was assessed following budbreak, and a graft was classed as surviving if at least one shoot grew from any position on the scion. Overall graft survival was 67% for Merlot and 53% for Chardonnay, but only 7% for Syrah which grew very vigorously into the fall and had difficulties lignifying its shoots. Scion survival also varied significantly (p less than 0.001) with rootstock, with 101-14 being the highest at 73% survival and 110R the lowest at 28% survival (excluding Syrah). Many plants of the rootstock 110R had died following the cold event, so that scions
could have been killed due to the death of the rootstock rather than due to freezing injury per se. Thus 110R may not be cold-hardy enough for Washington conditions. Interestingly, Merlot performed best when grafted to 140-2, whereas Syrah and Chardonnay did poorly on this rootstock. Moreover, grafting height dramatically (p less than 0.001) affected survival rate across varieties, with 65% of the 27 in. grafts surviving, but only 23% of the 10 in. grafts.
Impacts
Results from this study are critical to the success of using grafted grape plants under Washington's climatic conditions. Even though the experiment is still in its establishment phase, preliminary results have already been used by growers to select appropriate rootstocks and change varieties quickly in the field through field-grafting. Cost and time savings due to field-grafting technique introduced by us have been substantial when compared to the costs of standard practices, which include complete removal of all vine and trellis material from a block, leaving the block fallow for at least one season, replanting and retrellising, and training young vines for three years before the first crop.
Publications
- No publications reported this period
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