Effects of the First Bearing Age on Tree Growth, Fruit Yield and Quality of Satsuma Mandarin ‘Otsu-No. 4’ Grafted on Dwarf Rootstock ‘Hiryu’

Abstract

Effects of different first bearing years (3, 4, or 5 years after planting) on the tree growth, yield and fruit quality of satsuma mandarin (Citrus unshiu Marcow. cv. 'Otsu-No. 4') trees grafted on dwarf rootstock 'Hiryu' (Poncirus trifoliata (L.) Raf. var. monstrosa) were investigated. No relationship was found between the first bearing age and fruit quality. The later the first bearing, the larger the canopy volume became, however, trees that began to bear from 5 years after planting were large and higher alternate bearers. On the other hand, trees that began to bear from at 3 years after planting showed less growth and production. In consequence, trees that began to bear from 4 years after planting (tree height 172 cm, canopy volume 3.2 m 3) had the best productivity and work efficiency.