Effect of planting density on leaf growth of 'Starking Delicious' apple trees grafted on dwarfing and semi-dwarfing rootstocks.

摘要

The effect of planting density on the leaf growth of Starking Delicious apple trees grafted on dwarfing (M.9 and M.26) and semi-dwarfing (M.7 and MM.106) rootstocks, was studied. On all 4 rootstocks, the mean area per leaf and the mean dry weight per leaf tended to decrease, but the specific leaf area (SLA) increased, as planting density increased. On all rootstocks, the leaf dry weight per tree, the leaf area per tree, and the leaf number per tree decreased, but the leaf area index (LAI) increased, as density increased. Relationships between these parameters were represented by equations. No relationship was found between fruit yield per hectare and LAI. However, a high correlation coefficient was found between fruit yield per hectare and fruit production rate per unit leaf area, independent of tree age and rootstock.