The Effects of Apple Clonal Crown Rot Tolerant Rootstocks Series on the Growth Control of Scion Cultivars

The 2- and 3-year-old of 60 apple combinations of 'Golden Delicious' and 'Red Delicious' onto promising clonal rootstocks tolerant to crown rot series along with 6 common clonal rootstocks were assessed for dwarfing potential. Branch length and number, internode length, active vegetative buds, annual shoots growth and diameter, sapling height, growth habit, root-sucker number and length per sapling, diametric values of rootstock, graft point and scion as well as pest/disease damages were assessed. The modified dwarfism ranking method was achieved in 5 groups, based the length of lateral branches per sapling. So, the rootstock series were ranked in very dwarfing (8 hybrids), dwarfing (6 hybrids), mid dwarfing (6 hybrids), vigorous (7 hybrids) and very vigorous (3 hybrids). The three categories of very-dwarfing, dwarfing and mid- dwarfing had the least shaded area compared to controls as the worldwide dwarfest ones. ANOVA and mean comparisons by Dunken test of the growth traits particularly lateral branches length and number, sapling height and annual branch length of the two scion cultivars was achieved related to M7 combinations. The trial was compiled within RCBD.