Management implications of the distribution of fruit set on breadfruit (Artocarpus altilis) trees

The study was conducted to determine whether position on the canopy, canopy orientation, location of the tree within the row and time influenced fruit set distribution on the canopy and the implications for managing a pure stand breadfruit (Artocarpus altilis (Park.) Fosberg) orchard. Fruit set distribution was recorded from 1999 to 2001 on 18 seven-year old trees growing in two east to west-oriented rows and spaced at 12 m x 12 m in an orchard at the University of the West Indies, Trinidad. Tree size was also measured. The canopy of each tree was divided into quadrants designated Upper East, Lower East, Upper West and Lower West. The total number of fruits present in each quadrant was counted at two to three-week intervals. At the end of the bearing period, 55% and 52% of the fruit set was the upper quadrants and on the eastern quadrants, respectively, over the three years. The trend was more pronounced in the first week of bearing when 64% and 66% of the fruit were set in the upper quadrants and in the eastern quadrants respectively. Tree position in the row had a very highly significant (P<0.01) effect on cumulative fruit set and on the distribution of fruit set. Fruit set was very highly significantly (P<0.01) related to tree width (R-2=0.62) but the relationships with tree height, canopy depth and canopy volume were not significant. The results indicated that fruit set distribution was influenced by uneven tight interception by the canopy. The implications for orchard management strategies to improve light interception and reduce tree height, including row orientation, plant spacing and arrangement and, pruning are discussed.