Vine vigor, yield and grape quality assessment by airborne remote sensing over three years: Analysis of unexpected relationships in cv. Tempranillo

© 2015 INIA. The prediction of grape composition is becoming more important due to the need of reducing the current levels of alcohol and pH of the wines, a problem that is exacerbated by climate change. This work presents a 3-year study of the spatial variability of grape composition in a rainfed Tempranillo vineyard located in Rioja (Spain). It is based on the acquisition of multispectral imagery at véraison (start of the ripening process); and zoning based on NDVI, to assess its performance for zonal management. The results reveal a high spatial variability within the plot, with a stable pattern over the years, even with very different climate conditions. NDVI was a good predictor of vegetative growth variables. However, the prediction of grape composition was more complex. Unexpectedly, anthocyanins were found to be higher in the highest vigor zone, which is probably related to the effects of climate change. This unexpected relationship is particularly discussed in the article.This work was financed by a CDTI (Spanish Centre for Industrial Technological Development) program IDI 20110576 in Bodegas Eguren Ugarte (Laguardia, Álava, Spain).Peer Reviewe

Unexpected relationships between vine vigor and grape composition in warm climate conditions

[Aim] The purpose of the research was to link vigor with grape composition in a climate change scenario. [Methods and results] This work presents a 4-year study (from 2010 to 2013) in a non-irrigated Tempranillo vineyard located in La Rioja (Spain). It is based on the acquisition of multi-spectral imagery at véraison and a subsequent zoning in two different vigor zones based on NDVI (Normalized Difference Vegetation Index). All parameters related to vigor showed significant differences within the zones (total shoot length, leaf area, pruning weight). Unexpectedly, the content in anthocyanins was found to be higher in the highest vigor zone in most of the years of study, a point particularly discussed in this work. [Conclusion] Climatic conditions may affect considerably bunch microclimate and disturb the biosynthetic pathways of major grape components, leading to maturation mismatches. In hotter years, high vigor vines may favor anthocyanin accumulation through shading and protecting effects in the bunch area. [Significance and impact of the study] Many studies have shown a negative relationship between vigor and grape anthocyanins, but in the present research the opposite trend was observed in hot years.Peer Reviewe