FIRST RESULTS OF THE EVALUATION OF SIX PRUNUS INTERSPECIFIC ROOTSTOCK SELECTIONS IN COMPARATIVE TRIALS SET UP IN TWO DIFFERENT ENVIRONMENTS

Abstract

Peach culture is increasingly extended to areas which often do not offer soil conditions truly suited to this crop. Replanting, limestone chlorosis, soilborne pests and pathogens are among the most common problems in many Mediterranean basin countries. In a collaborative project supported by EU (1999-2003), interspecific crosses among different Prunus species originated several hybrid progenies, from which potential new rootstocks for the main stone fruit crops were selected for their resistance to biotic and/or abiotic stresses. Six of these were agronomically evaluated in two rootstock comparative trials set up in two important peach-growing areas located in the North (Romagna, Southern Po Valley) and South of Italy (Metaponto, Basilicata). In both trials, the rootstock selections P.2175 A— P. davidiana-1, P.2175 A— Garnem-3, P2175 A— P. davidiana-4, P2175 A— Garnem-16, P2980 A— Felinem-23 and P2980 A— Garnem-9 were compared with the peach A— almond hybrid GF677, susceptible to root-rot disease and by far the widest spread rootstock in Italy. The trial in Romagna was set up on a replanting soil infected by A. mellea, which had caused the explanting of the previous peach orchard; in addition to GF677, this trial included also GF43 (P. domestica) and Adesoto 101 (P. insititia) as control rootstocks, known as being endowed with some tolerance to this fungal disease. Although evaluation is still in progress, preliminary results showed variability for graft compatibility and induced vigour depending on the rootstock and on the scion cultivar. Total yield/tree was generally higher onto GF667, but some of the hybrid rootstock selections positively affected fruit size and sugar content, yield efficiency and/or significantly anticipated harvest time.