The effects of applied water at various fractions of measured evapotranspiration on reproductive growth and water productivity of Thompson Seedless grapevines

Abstract

The reproductive growth and water productivity (WP b ) of Thompson Seedless grapevines were measured as a function of applied water amounts at various fractions of measured grapevine ET c for a total of eight irrigation treatments. Shoots were harvested numerous times during the growing season to calculate water productivity. Berry weight was maximized at the 0.6-0.8 applied water treatments across years. As applied water amounts increased soluble solids decreased. Berry weight measured at veraison and harvest was a linear function of the mean midday leaf water potential measured between anthesis and veraison and anthesis and harvest, respectively. As applied water amounts increased up to the 0.6-0.8 irrigation treatments there was a signiWcant linear increase in yield. Yields at greater applied water amounts either leveled oV or decreased. The reduction in yield on either side of the yearly maximum was due to fewer numbers of clusters per vine. Maximum yield occurred at an ET c ranging from 550 to 700 mm. Yield per unit applied water and WP b increased as applied water decreased. The results from this study demonstrated that Thompson Seedless grapevines can be deWcit irrigated, increasing water use eYciency while maximizing yields.

Response of Table Grape to Irrigation Water in the Aconcagua Valley, Chile

“…The quality parameters firmness (Table 6) and sugar content (Table 7) were not affected by the irrigation treatment in any experimental year, and were in the normal range for this cultivar [33]. Williams et al [17] found an increase in berry sugar with water application under 60% of ETc in Thompson Seedless for raisins. However, juice acidity was between 0.7 and 0.8 mg of tartaric acid/100 mL juice in all years and treatments; these are considered normal values for this variety [33].…”

“…Means followed by a different letter within a given year are significantly different at P < 0.05. Williams et al [17], using Thompson Seedless cultivar grown for raisins, found a linear relationship between SWP and berry weight at harvest; berry weight increased with increased water applied up to 80% ETc, while more water beyond 80% ETc did not produce greater berry weight. This relationship was also linear in the present study, even for greater amounts of water.…”

“…Ezzahouani and Williams [20] found that under different irrigation treatments the cultivar "Danlas" obtained the highest yield and berry weight under well irrigated treatments. Williams et al [17,21] studied the effect of SDI on Thompson Seedless for raisin production, and concluded that application of water above 80% of the crop evapotranspiration (ETc) did not increase fruit yield, whereas below 60% ETc decreased berry yield and weight but increased soluble solids.…”

“…Berry quality variables of table grapes differ from those of wine grapes. In table grape, berry size, firmness, color, acidity and total soluble solids are important quality parameters [17]. There are a few RDI studies with table grapes where an irrigation restriction was imposed after veraison when berries have almost reached full size [18][19][20].…”

Improving water use efficiency of vineyards in semi-arid regions. A review

“…In consequence, an important volume of applied and fundamental research has been focused into the exploration of the capacity to optimize grapevine water use. An important part of these researches are related to the evaluation of irrigation timing and schedule by introducing new technologies to reduce water consumption (Chaves et al 2010;Romero et al 2010;Sadras 2009;Williams et al 2010). Regarding the improvement of genetic capacities to enhance WUE, some works have been focused on the estimation of the genetic variation of grapevine rootstocks or cultivars (Alsina et al 2007;Satisha et al 2006;Tomás et al 2012).…”