RESULTS OF A SWEET CHERRY ROOTSTOCK TRIAL IN NORTHERN POLAND

‘Rivan’, ‘Burlat’, ‘Merton Premier’, ‘Büttner’s Red’ and ‘Hedelfinger’ sweet cherry trees grafted on PHL-A (syn. P-HL 84), PHL-C (syn. P-HL 6), MaxMa Delbard^® 14 Brokforest (MaxMa 14) and F12/1 clonal rootstocks, as well as on Mazzard seedlings, were investigated for growth, yield, fruit weight, tree decline and suckering. The field experiment was conducted, without irrigation, at the Experimental Station in Milobadz from 1992 to 2000. The trees on F12/1 were regarded as a control.
The growth of 9-year-old trees was reduced significantly by both PHL rootstock types, more by C than A. The dwarfing effect of MaxMa 14 was similar to PHL-C. No significant differences were found in vigor between trees grafted on Mazzard and F12/1. Cumulative yields and the productivity index for trees on PHL rootstocks and MaxMa 14 were higher than for those on F12/1. Those rootstocks that reduced tree growth also exhibited reductions in fruit size. However, the trees on MaxMa 14 had a higher tendency to decrease the mean fruit weight than did those on PHL-A and PHL-C rootstocks. During the first year after planting, all ‘Hedelfinger’ trees on PHL-A declined from an apparent physiological incompatibility between rootstock and scion. Suckering was not a problem in this trial.