Producing plant material at intermediate grafted apple

Abstract

Tree precocity represents an important characteristic that shortens the youth of the tree and influences the cost of maintenance of the orchard during the first years of production. Low vigour rootstocks ensure precocity but do not always ensure a good ramification and are more demanding in terms of culture conditions. Testing the way apple tree behaves using seven varieties ('Pinova', 'Sirius', 'Mutsu', 'GoldRush', 'Mars', 'Karneval' and 'Topaz') grafted in eight combinations out of which four with an intermediary stock showed different reactions determined by the rootstock and by the intermediary itself regarding tree height, capacity to form branches of fruit and fruit buds. Tree height was influenced by the vigour of the rootstock; the largest trees were produced using the rootstock 'MM106' while the 'B9' used as interstem greatly reduced the vigour of the trees grafted on 'A2' and 'MM111'. The ramification capacity depended on the grafting combination; the number of formed branches per tree had values between 0-13.4 depending on the rootstock, the interstem 'B9' having a positive influence on the result. The number of fruit buds formed in the plant nursery without any interventions on the trees was greatly influenced by the grafting interstem, the growth being of over 50% for all tested combinations. Thus the use of interstems represents an alternative to produce trees with fruit branches in plant nurseries.