SEMI-COMMERCIAL EVALUATION OF PROMISING IMPORTED ROOTSTOCKS

The rootstocks Thomas, Barr-Duke, D9, G755 and Duke 7 are being evaluated for Hass avocado on a semi-commercial basis (220 trees per rootstock) in the Tzaneen-Duivelskloof area. The potential low-vigour rootstocks Wilg, Ryan and Colin V-33 are also being compared to Duke 7. Wilg has had a significant dwarfing effect on Hass, but production potential of this rootstock is not yet known. To date, Colin V-33 interstock has decreased the vigour of Hass only slightly. Drought has influenced the results of the evaluation and, at this stage; the only recommendation is to continue with Duke 7 as a rootstock for Hass