Apple yield and quality as affected by training and shading

Fruit yield and quality were investigated on five-year-old apple trees (Malus domestica Borkh. cv. Cox's Orange Pippin) on M9 rootstocks growing in field lysimeters, as affected by training to Y-trellis or slender spindle at full light exposure or 60 % shading treatment in the fourth growing season after planting. In comparison with the spindles and shaded trees, Y-trellis and exposed ones bore more fruits and got higher fruit yield with heavier average fruit weight and larger fruit size. Contents of dry matter, total soluble solids, the solids/acid ratio, starch, glucose, fructose, sucrose, sorbitol and total non-structural carbohydrates were higher in fruits from Y-trellis and exposed trees than those from the spindles and shaded ones. In addition, shading treatment increased N, P, K and Mg contents and K/Ca ratio, especially in K and Mg, but tendenciously decreased Ca content of fruits. Incidences of physiological disorder and fungi diseases of fruits during five months' storage were lower from shaded trees and the spindles than those from exposed and Y-trellis trees.