Abstract

In the Aconcagua Valley, Chile, a 5-year research (2007/2012), has been carried out to evaluate the response of table grape 'Thompson Seedless' vines to different volumes of irrigation water. The experimental site was a commercial orchard of 'Thompson Seedless' grafted on Freedom rootstock, located in the Aconcagua valley (70 degrees 41'23 '' W. Long. and 32 degrees 47'20.9 '' S. Lat.), Chile. Four irrigation treatments were applied: 60, 90, 120 and 140 percent of crop evapotranspiration (ETc) during the seasons 2007/08 to 2010/11, and 40, 54, 92 and 108% of Etc in the last season (2011/12). Soil water content was monitored with a capacitive probe in each treatment. Midday stem water potential was also measured. Soil available water as a result of irrigation treatments affected berry size distribution. A linear relationship between berry size and SAW was found. The bunch weight was also affected by a lower application of water (60% ETc). Maximum exportable yield was obtained in the 120% ETc treatment. Table grape production was lowered either by a water application of less than 90% ETc or more than 120% ETc. In the former case, yield reduction may be related to soil water deficit. In the latter case it may be related to poor soil aeration. The water use efficiency changed, on the average, from 7 kg/m(3) of exported fruit at 40% ETc to 2.3 kg/m(3) with water applied at 140% ETc.