The effects of budding height on the field performance of two apple cultivars on three rootstocks

Abstract

SummaryLarge rootstock layers of virus-free M.9, M.26 and MM.111 rootstocks were budded with cvs Cox’s Orange Pippin and Golden Delicious at 150,300,450 or 750 mm above ground level and compared in a field trial lasting nine years. After five years, budding at 750 mm had reduced the total extension growth of cv Cox by 41% on both M.9 and MM.111 and by 60% on M.26 in comparison with low budding. Intermediate heights gave a roughly proportional reduction. Total yields were much less reduced by high budding which therefore increased the cropping efficiency of the trees. The effects were similar with cv Golden Delicious but less pronounced. After the fifth year trees on MM.111 were relatively less dwarfed by high budding whereas on M.26 the effect was increased. There was very little reduction in fruit size with high budding in spite of increased cropping efficiency except when extreme dwarfing led to very high ratios of crop to tree size. The initial reduction in vigour is believed to be due largely to the r...