Influence Of within-tree and environmental factors On fruit quality of cactus Pear (O. ficus-Indica)

Introduction. Opuntia ficus-indica fruit quality was studied, in the main sites for cactus pear cultivation in Italy, with the ultimate goal of understanding the main sources of variability and increasing crop value. Materials and methods. A first study was carried out in 2006 on mature Opuntia ficus-indica trees, cvs. Gialla and Rossa, grown in ten commercial orchards located in the main sites for their cultivation in Italy. Trees were managed to produce an out-of-season crop in October, through the removal of the spring flush at bloom time, during the first week of June. Trees had a similar crop [(52 ± 10) kg of fruits•tree-1], and no more than six fruits were left on each of the fruiting cladodes. At commercial harvest time, indicated by the peel colour breakage, 75 fruits in each orchard and 750 fruits for each site were picked, analysed and evaluated by a consumer panel. A second experiment was carried out in 2006 on 8-year-old O. ficus-indica trees, cv. Gialla, grown in a commercial orchard. Within-tree factors, such as fruit position within the canopy, number of fruits per tree and per cladode, and cladode dry weight were studied. Results and discussion. Fruit weight, shape and total soluble solid content significantly changed with the environmental conditions, i.e., site and altitude, while flesh percent, pH and total titratable acidity did not. Cultivars had a significant influence only on fruit weight and seed content. Fruit weight changed greatly within the tree, while total soluble solid content and flesh percent variability was much reduced. Fruit weight decreased with fruit number per tree and both fruit weight and total soluble solid content decreased with more than six fruits per cladode. Light interception and cladode dry weight were the main sources of fruit dry weight variability and sugar content, while cladode surface area was poorly related to fruit quality. The role of cultivars in determining fruit quality did not change with site and, moreover, the sensory analysis was unable to discriminate for cultivar and environment.