Influence of Four Apple Cultivars on Five Dwarfing Rootstocks on Morphology of Two-Year-Old Limb Sections

Abstract

Morphological characteristics on two-year-old stem sections of four apple cultivars on five dwarfing rootstocks (M.26 EMLA, O.3, M.9 EMLA, B.9, Mark) were measured in Wooster, OH, Manhattan, KS and Wichita, KS from 1994-1996. Location and year had the greatest influence on all the morphological characters. Rootstock had minor influence on morphological characters measured, while cultivar had a significant influence. Stem length of all cultivars and rootstocks was positively correlated to spur and shoot numbers. For most of the cultivars and rootstocks, yield was positively correlated with density for flowering spurs and negatively correlated with stem length. Consistently for all cultivars M.26 EMLA and O.3 produced the longest stems and had the most spurs/stem, while the opposite was true for MARK and B.9/ the data in this study supports the theory that rootstock controls total growth and cultivar controls distribution of growth. However, the cultivar rootstock interactions show that some rootstocks were able to cause slight changes in the distribution of growth of a given cultivar.