Fruit quality of four cactus pear (Opuntia ficus-indica Mill.) cultivars as influenced by irrigation

Because of its high drought resistance, the cactus pear in Mediterranean countries is generally cultivated without water supply. Previous experiences, however, have indicated that low volume irrigation on Sicilian cultivars improved fruit yield and quality. To study the effects of irrigation on cactus pear fruit quality, a field experiment was performed using four different cultivars: three of Sicilian origin ('Gialla', 'Rossa' and 'Bianca'), and one selected from the Sardinian germplasm ('Gialla sarda'). Six irrigated plots of eight plants and six unwatered plots were planted for each cultivar with 2.5x5m as planting distance. The experimental design included six completely randomized blocks. The seasonal volume of trickle irrigation was 1700 m(3) in the first six years. Fruit yield per plant in irrigated plots was at least two folds higher than yield in unwatered plots. The higher yield in irrigated plots derived from higher fruit number per cladode, but the fruit weight was not influenced. The increase in fruit peel thickness from irrigated plants reduced the juice percentage and irrigation also increased the seed weight. Pulp reducing sugar content and peel dry weight was generally lower in irrigated fruit, but the differences from cultivar to cultivar were relevant and not uniform.