|REEVE, ALISON - Oregon State University
|SKINKIS, PATRICIA - Oregon State University
Submitted to: Oregon Wine Research Institute
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2014
Publication Date: 4/1/2014
Citation: Reeve, A.L., Skinkis, P.A., Lee, J., Tarara, J.M. 2014. Vine balance: relationships between Pinot noir vegetative vigor and fruit composition. Oregon Wine Research Institute. Meeting booklet.
Technical Abstract: Vine balance metrics have been determined in hot climates to help growers quantify vine growth in relation to crop level to produce high quality fruit. A study was implemented in a commercial vineyard to evaluate a range of crop loads in relation to vine growth and fruit quality. Vegetative vigor was decreased moderately or severely by growing a perennial grass cover crop in either or both of the adjacent alleyways, respectively. The cover crop decreased nitrogen in vine tissues during 2011-2013, but did not decrease soil moisture in 2012-2013 or plant water stress in any year. Two crop levels were established by leaving all crop on the vine or thinning to one cluster per shoot. Total soluble solids (TSS) decreased as Ravaz increased over the range of 0.52 to 3.74 experienced in this study (p<0.0001). TSS increased as the leaf area to yield ratio increased in each year. Anthocyanin (ACY) concentrations increased as the ratio of leaf area to yield increased, despite the decreased solar radiation in the fruit zone. Within any year, anthocyanin concentrations increased when yields were reduced, but were not affected by leaf area. Total phenolic (PHE) concentrations did not depend on Ravaz, as they decreased with yield (p=0.0008) and were not affected by pruning weight. Total tannin concentrations were not influenced by vine balance, except when they increased with Ravaz in 2013. Tannin concentrations were associated more with vegetative growth such as pruning weights and leaf area rather than yield. This research suggests that a lower Ravaz Index than the previously suggested 3-6 may be more suitable for this region and cultivar as higher vigor vines had the capacity to produce fruit with similar ACY and TSS at slightly higher yields than those with a higher Ravaz Index (lower vigor) in this trial.