Plant growth and fruit quality as affected by canopy locations in ‘Shiranuhi’ mandarin

Fruit quality (soluble solids and acidity) and growth properties of fruiting branches in different canopy positions (upper, middle, and lower) of ‘Shiranuhi’ mandarin [(C. unshiu × C. sinensis) × C. reticulate] trees were determined during fruit maturation. Length, diameter, and number of leaves per fruiting branch increased in order from the upper, through the middle, to the lower parts of the canopy. Fruit diameter, fruit weight, pulp weight and pulp thickness were also highest in the upper part. Transverse sections of stem end protrusions in fruit from the upper, middle, and lower parts of the tree canopy were 37.3 ± 2.3 mm, 33.2 ± 0.2 mm and 32.1 ± 0.4 mm, respectively. Soluble solid content increased during fruit maturation at all locations within the canopy and was highest in the upper part. Likewise, acid content decreased with fruit maturity and was lowest in the lower part. These results suggested that harvesting be staggered starting with fruit from the upper part of the canopy as part of crop management in ‘Shiranuhi’ mandarin for direct effect on fruit quality.