Relationships between apple tree rootstock, crop-load, plant nutritional status and yield

摘要

Impact of the choice of rootstock and crop-load on apple tree nutritional status and yield relationships between biochemical parameters were analysed. Apple cultivar `Ligol' was grafted onto semi-dwarfing rootstock M.26; dwarfing rootstocks M.9, P 67 and B.396; and super-dwarfing rootstock P 22. Crop-load was adjusted to 60, 105 or 150 inflorescences per tree. Flower buds were removed at the pink bud stage. Super-dwarfing P 22 rootstock under intensive crop-load (150 inflorescences per tree) resulted in N deficiency in the leaves, which caused an accumulation of leaf sugars. Leaf elements were influenced by rootstock and crop-load. With the dwarfing rootstocks P 67 and B.396, a significantly larger leaf area and a decrease in photosynthetic pigment and leaf carbohydrate content were observed. Apple tree yield was directly correlated with the crop- load and the number of fruits, independent of the rootstock onto which they were grafted. Average fruit weight, independent of rootstock, was inversely related to crop load. Generally, yield, fruit weight were crop-load, while metabolite changes were rootstock dependent. Mineral sufficiency was dependent on rootstock and crop-load. Super-dwarfing P 22 rootstock resulted in the smallest yield and fruits. (C) 2016 Elsevier B.V. All rights reserved.