Effect of several new Polish rootstocks and M.9 subclones on growth, yield and fruit quality of two apple, 'King Jonagold' and 'Elshof' cultivars.

摘要

The experiment was carried out in Central Poland from 1997 to 2001. The influence of new Polish dwarfing and semi-dwarfing rootstocks, as well as subclones of M.9, on the growth, yield and fruit quality of 'King Jonagold' and 'Elshof' apple cultivars was studied. The results showed that the new Polish rootstocks P 61, P 63, P 64, P 65 and the Byelorussian PB-4 decreased tree growth of both cultivars. Sizes of these trees were significantly smaller, compared to P 22 (control). Growth of trees grafted on rootstocks of German selections of M.9, B.1, B.2 and B.3 was similar to those of trees on M.9 EMLA (standard). The new Polish very dwarfing rootstock selection, P 62, significantly decreased tree growth, compared to M.9 EMLA (control). Among the semi-dwarf rootstocks tested, P 67 reduced tree growth to the same degree as M.26 (control). For 'King Jonagold', P 66 appeared to be a more dwarfing rootstock than M.26. The highest cumulative yield of both cultivars was obtained from trees grafted on the semi-dwarfing rootstock P 67. Tree productivity results, expressed as the yield efficiency index, showed that 'King Jonagold' trees on all rootstocks were more productive than those of 'Elshof'. The highest yield efficiency index achieved with 'King Jonagold' was obtained from trees grafted on P 63 and P 64.