Effects of irrigation at critical crop stages on fruit yield and quality of cactus pear (opuntia spp.)

The effects of three irrigation doses at two critical stages on fruit yield and fruit quality of three varieties of cactus pear (the spineless ‘Aissa’ and ‘Moussa’ and the thorny ‘Achefri’) in the Agadir area were recorded for two years (2011 and 2012). In 2011, irrigation treatments were: the control T1 (0 mm), T2 (30 mm during flowering (mid-April) and 30 mm during fruit enlargement (mid-June) and T3 (30 mm only during fruit enlargement). In 2012, the irrigation dose was doubled (60 mm) and irrigations were applied at flowering (February) and at the beginning of fruit growth (May). In 2011, irrigations had a negative effect on ‘Moussa’ and ‘Aissa’ cultivars (less than 2.8 kg/plant) and a significant positive effect on the ‘Achefri’ cultivar (+2.7 kg/plant for T2). Fruit quality, including size and its chemical features, were not affected by the irrigation doses. In 2012, all three varieties reacted positively to irrigation: ‘Aissa’ and ‘Achefri’ yielded best with a T3 irrigation and Moussa with the earlier and higher dose T2 irrigation. Yield increment varied between 30% for ‘Moussa’ to 63% for ‘Achefri’. Differences in yield originated both from more fruit and higher single fruit weights. Irrigations increased fruit size (fruit weight, length and diameter) and fruit number and slightly decreased titrable acidity and the content of total sugars. Irrigations had no significant effect on the amount of juice in fruits, juice dry matter, pH and degree Brix values.