Wood and tree age as factors influencing the ability of apple flowers to set fruit

SUMMARYThe different fruit setting ability of flowers borne on different aged wood and trees of 'Cox's Orange Pippin'apple was examined. Developmental and physiological changes of flower buds were examined from bud burst to full bloom and related to their ability to set fruit. The capacity of apple flowers on young wood to set fruit was considerably less than that on older wood and although fewer fruits were retained until final set, it was the lack of initial set that limited cropping. There were gross morphological differences between flowers on different aged wood. Flower clusters on young wood typically had smaller leaf areas and mean flower weights as well as fewer flowers than those on older wood. The reduction in flower cluster size did not appear to be the obvious result of competition between reproductive and vegetative growth for mineral nutrients. Female fertility, effective pollination period, and the microscopical anatomy of flowers were also examined. Flowers on both young wood and trees sho...