Propagation of Selected Pear and Quince Rootstocks By Hardwood Cuttings

As long as new rootstocks continue to be developed, there will always the need for new genotypes to be controlled and evaluated. This study involves verification of selected rootstocks with reference to growth, propagation ability and other characteristics. Different rootstocks, different growth stimulators and different kinds of cuttings techniques were adopted for these experiments. Stimulators used for evaluations included: 1 % Racine (2.5 % naphthalene acetic acid - NAA), 0.5 % Rhizopon AA (2.5 % indole-3-butyric acid - IBA) and 0.25 % IBA in 50 % ethanol solution. There were three sets of experiments in all. In Experiment 1, the bases of cuttings were treated with the stimulators and part of them was also treated with heat before planting. Results from Experiment 1 indicated that cuttings treated with Rhizopon AA produced the best effect after heat treatment (with an overall average of 36.9 % of rooted cuttings). Pyrodwarf (78.7 %), Cydomalus (73.9 %) and Pyroplus (60.6 %) were the best performing rootstocks among the evaluated ones. In Experiment 2, we evaluated the influence of the date of harvesting the cuttings on rooting (comparisons were made between cuttings prepared in December [early] and March [late]). For BA29 rootstock cuttings, the best performance was attained by cuttings taken in March. The difference in rooting between March and December was 43.9 %. On the other hand, early harvested rootstocks (cuttings taken in December) for Cydomalus showed the best performance, with an 18.7 % difference between cuttings made in December and in March. Results from other evaluated rootstocks were not significant enough. In Experiment 3, the effect of chemical (phytohormone) stimulation and heat stimulations was compared. The best result was obtained by combinations of treatments without heat stimulations, when the cuttings were stored at 5°C and later treated with 0.25 % IBA in 50 % ethanol solution. The least rooting results, on the other hand, were observed in heat treated cuttings, in cuttings stimulated with IBA and subsequently with heat and in cuttings treated with a 3 cm radial cut at the base. Based on our findings we cannot prove clearly that heat stimulation and the phytohormones used have beneficial effects on rooting of especially new rootstock genotypes with an unknown propagation coefficient. This means that propagation using cuttings still remains an interesting topic to be further researched.