Effects of foliar application of NAA on shoot growth, fruit quality, and return blooming in 'Fuji' apple trees.

摘要

The effects of NAA on shoot growth, fruit quality and return flowering in the following season of Fuji apple trees on M.26/seedling and M.9 were evaluated for one year in a high density orchard system. NAA, at a high concentration of 10, 20 and 30 mg/litre, was sprayed from 70 days after full flowering (2 applications with a one week interval) on Fuji/M.26/seedling. NAA at 10, 20, 30 and 40 mg/litre was sprayed from 60 days after full flowering (3 applications at intervals of one week) and from 70days after full flowering (2 applications with a one week interval) on Fuji/M.9 apple trees. Shoot growth and regrowth rate were significantly decreased by two foliar applications of NAA on Fuji/M.26/seedling and 2 or 3 foliar applications of NAA on Fuji/M.9 apple trees. Fruit weights were increased by 2 or 3 foliar applications of NAA in Fuji apples on both rootstocks. Fruit firmness and soluble solid contents were higher than the control after 2 applications of NAA on Fuji/M.26/seedling, but there were no differences between NAA treatments and the control in Fuji/M.9 apples. The number of return flowering clusters was increased by foliar applications of NAA in Fuji apple trees in both rootstocks. With these results, we can estimate that 2 or 3 applications of NAA at a concentration of 10 to 40 mg/litre can control the canopy size in high density orchard systems.