Assessment model for scion/rootstock interaction in cherry compatibility.

Abstract

SUMMARY Breeding process of cherry rootstocks aims to obtai n a large spectrum of vigour, which new rootstocks give to trees by grafting. The inter actions of rootstock to varieties and expression of their compatibility are complicated, but essential in choosing the best combination variety / rootstock (Hrotko, 2004; Sita rek, 2006). Making a database support for optimal graft combinations and designation of the m ost valuable biotypes in terms of agroproductivity potential is a step forward in achievi ng sustainable fruit systems. Therefore, the main objective was to emphasize new elements of the compatibility and incompatibility at cherry such as forms, manifestation, early expressi ons related to the morphological and metabolic changes. The tested rootstocks were inter specific hybrids as follows: Prunus subhirtella x Prunus canescens, Prunus pseudocerasus x Prunus inc isa, Prunus incisa x Prunus subhirtella and Prunus subhirtella x Prunus pseudocerasus. Sweet cherry varieties used as scions were ‘Van’, ‘Van C’, ‘Starking’, ‘Ne ro 2’, ‘Nero 3’ and ‘Durone di Batza’. In the nursery field, it was observed a lot of interes ting scion/rootstock interactions, which we concentrate them in models for cherry incompatibili ty. Earliest form of incompatibility is evidenced in the bud stage, when the scion began ex panding, but in the end is withering and it drops. Another manifestation of incompatibility is the one when the bud is expanding, is opening, but the rootstock eject the scion in that condition. In a different phenologic phase the incompatibility symptoms starts after three weeks w hen the leaves are opened but a senescence metabolic process interpose and it is di stinguished by chlorotic yelowed leaves which premature drops. In the next phenological sta ge, incompatibility is manifested by a very slow rhythm of scion growing. At the end of ve getation, the shoot stays in the spur type. In any development stage of the scion, a very negat ive influence of the rootstock may appear more or less intense by eluding tendency of the sci on shoot or branch. Also in many cases, the scion is detached and the mechanical resistance of the grafted plant is compromised. In conclusion, many of the incompatibility forms are l ocalized in the grafting zone and are morphological emphasized.