COMPARISON OF SEVERAL PRUNUS HYBRIDS AND PEACH SEEDLINGS USED AS ROOTSTOCKS FOR 'MAYGRAND' NECTARINE

Several peach rootstocks - five Prunus Besseyi interspecific hybrids ('299', 'Manson', 'Sapa', 'S. Anthony' and 'Yuksa'), three Prunus Besseyi clones ('B. 25/1', 'B.25/3' and 'B.25/6'), two peach seedlings ('P.S.A1' and 'P.S.A2') and one Prunus tomentosa seedling - were grafted with 'Maygrand' nectarine and compared in a four years trial at the I.C.A. Experimental Station in Pisa.

Graft incompatibility was highest in 'Besseyi 25/1' (67%), 'B.25/6' (70%), 'B.25/3' (100%) and Prunus tomentosa (100%), and intermediate in 'Sapa' (25%), 'Yuksa' (15%) and 'Manson' (50%). The rootstocks '299', 'P.S.A1', 'P.S.A2' and 'S. Anthony' showed a good compatibility.

For vigour and yield, during the first four years period, it is evident that the more vigorous was the rootstock ('299', 'P.S.A1' and 'P.S.A2'), the higher were the yield and tree crop efficiency. 'Yuksa', 'S. Anthony' and 'Sapa' proved to be about 20% less vigorous than the peach seedlings, but yields were 60% lower. Our result suggest avoiding the former rootstocks for high density plantings.

The interspecific hybrid '299', in the environment conditions of the trial, induced a good level of vigour, uniformity of behaviour and high productivity.