Growth and yielding of 'Jonagold' and 'Ligol' apple trees on M.9 and P 22 subclones, and some other Polish rootstocks.

The effect of subclones of M.9 (M.9T 337, Pajam 1, RN 29), P 22 (P 22/K, P 22/A, P 22/J), and some new Polish rootstocks (P 59, P 60, P 61 and P 62) on the growth and yielding of ‘Jonagold’ and ‘Ligol’ apple trees was studied in a field experiment over a period of 10 years. The vigour of both cultivars on subclones M.9 was very close to that on the standard rootstock M.9 EMLA, but trees on Pajam 1 were the smallest. Trees ‘Jonagold’ grafted on the new Polish rootstock P 62 were significantly less vigorous than those on M.9 EMLA. Tree vigour of both cultivars on the subclones of P 22 was similar to that on the standard rootstock P 22. ‘Jonagold’ trees grafted on P 61 were significantly smaller than the standard trees on P 22. The smallest trees of both cultivars were obtained on P 59. In the group of semi-dwarfing rootstocks, the smallest trees were on P 60 and the largest on P 14. Yields were more or less proportional to tree size. Among the subclones of P 22, the highest cumulative yields for both cultivars were obtained on P 22/A. The highest cumulative yields for both cultivars on the M.9 subclones were obtained on M.9T 337 and, in the semi-dwarfing group, for ‘Jonagold’ trees on P 60 and ‘Ligol’ trees on P 14. The values of the yield efficiency index for the subclones of M.9 were similar to those for M.9 EMLA, and among the subclones of P 22 the values of this index were similar to those for the standard P 22 rootstock. The highest yield efficiency index among the... [to full text]