The investigation of trunk cross-sectional area (TCSA) and yield of apple cultivars Alkmene, Elstar, Hi Early and Golden Delicious clone B was done over four years (from 4th to 7th year after planting). Apple trees were grafted on rootstocks M.26, MM.106 and on MM.106 with M.9 as interstock. Trees were trained as slender spindle. Trunk cross area as the best indicator of the growth of the whole tree, expressed specific interaction between cultivars and rootstocks. TCSA of cvs. Alkmene and Elstar was bigger than TCSA of other cultivars, especially in combination with MM.106 rootstock, while TCSA of these cvs. grafted on M.26 and MM.106 with M.9 as interstock was almost the same. TCSA of cv. Hi Early was lower and of cv. Golden Delicious clone B the lowest. Yield increment (t/ha) was different for particular cultivar. It was evident that cv. Alkmene reached full cropping very late, while cvs. Elstar and Hi Early showed tendency to biennial yielding. The best yield was obtained with cv. Golden Delicious clone B when it was grafted on M.26 rootstock. Generally, examined cvs. exhibit better yield efficiency (kg/cm2 TCSA) on MM.106 rootstock with M.9 interstock. The best yield efficiency reached cv. Golden Delicious clone B.

apple; rootstock; interstock; vegetative growth; yield

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia