Effect of Rootstocks and Interstems on Composition of ‘Delicious’ Apple Leaves1

Abstract

Abstract Leaf nutrient composition (N, P, K, Ca, Mg, Mn, Fe, Zn, and Cu) was determined for 10-year-old ‘Delicious’ apple trees (Malus domestica Borkh.) grown on 21 rootstock and interstem combinations classified according to vigor (standard, semi-standard, semi-dwarf, dwarf). Significant differences in leaf P, K, and Mn were observed between the 4 vigor classifications. P and K were higher in leaves of standard than in leaves of dwarf trees, but leaves of dwarf trees had higher Mn than those of the other size classifications had. “Delicious”/Malling (M)7/Alanarp (A) 2 (dwarf) and ‘Delicious’/M7/Robusta (R) 5 (semidwarf) contained high K and low Mg levels. High Mg and low K were found in dwarf trees on M 2 and M 26 rootstocks. Calcium was higher in leaves of trees on Mailing Merton (MM) 106 rootstock than in those on M 7/MM 104. Trees on M 26 had high Mn. Fruit yield was correlated negatively to tree size and leaf K and positively to leaf Mg and Mn. Other elements were unaffected by the rootstock systems tested, which suggested that the rootstock and interstem combinations had only a minor effect on nutritional status of scion leaves.