José Ramón Lissarrague

Effect of irrigation on changes in the anthocyanin composition of the skin of cv Tempranillo (Vitis vinifera L) grape berries during ripening

The impact of water availability on the yield and on the chemical composition in the skins of cv Tempranillo grapes at different phases of berry growth was studied over a 2 year period by determining changes in berry weight, °Brix, titratable acidity, pH and different phenolic compounds. The evolution of phenolic compounds during berry growth followed similar patterns to those reported by previous investigators. Over the 2 year study, concentrations of total phenols and total tannins in the skins were always higher for the non-irrigated than for the irrigated vines, though the differences were not significant on some sampling dates. Total anthocyanin concentrations in 1992 were significantly higher in the non-irrigated than in the irrigated grapes, except at veraison and harvest. In contrast, in 1993, concentrations were higher in the non-irrigated grapes on the first three sampling dates and in the irrigated grapes on the last three sampling dates, but with significant differences only on day 136 after budbreak. In the first year, anthocyanin concentrations for the non-irrigated grapes were higher than for the irrigated grapes, except at harvest, though the differences at harvest were not significant. However, in the second year, concentrations in the berries from the irrigated vines were significantly higher on most sampling dates. In both years, concentrations of the five anthocyanins at harvest were higher for the irrigated treatment, the treatment that produced higher berry weights and crop yields. © 2001 Society of Chemical Industry

Vegetative Development: Total Leaf Area and Surface Area Indexes

Canopy management determines canopy shape and spatial leaf area distribution which in turn determines vineyard productivity. There are two indexes evaluating vineyard productivity which involve leaf development: total leaf area – LAI – and external leaf area – SA –. The first one refers to total leaf area developed per m2 of soil while SA refers to the external leaves, assuming that most of photosynthesis – 90% – is carried out by those leaves. This chapter aims to provide a feasible methodology to calculate both LAI and SA under different training systems and cultivars in order to predict vineyard productivity or/and to make decisions along the season. Relations between main leaf nerve length (cm) and leaf surface area (cm2) are given for Airen, Albarino, Barbera, Cabernet franc, Cabernet sauvignon, Chardonnay, Godello, Garnacha, Graciano, Mencia, Merlot, Petit verdot, Pinot noir, Semillon, Syrah, Tempranillo, Treixadura, Verdejo and Viognier.

Radiation Balance in Vineyards

Light intercepted by grapevines is linearly related to vineyard productivity. Radiation intercepted is also linked to vegetative development and in turn with water consume by plants. Thus, potential yield and crop coefficient – kc – for irrigation management can indirectly be predicted based on canopy light interception and vegetative development. The radiation balance of a crop can be calculated as absorbed radiation (Ra) or intercepted radiation (Rit). Ra is the balance between the input of radiation in the vine-soil group (incident radiation –Ri- and reflected radiation by the soil –Rrs-) and the output of radiation from the vine-soil (transmitted radiation –Rt- and reflected by soil and plant together –Rrsp-). In crops in rows, the soil between rows must be taken into account especially in those periods when the canopy does not cover it completely, representing a drain of energy. But once the development of the canopy is complete, Rit can be used as a simplification of Ra. Rit is the difference between Ri and Rt, without considering the reflected radiation because its value is very small.