Preliminary results of research on new apple rootstocks in South Africa
The entire range of apple rootstocks currently available to South African commercial growers has been found to have disadvantages in terms of some of the following aspects: vigour, yield efficiency, precocity, adaptability, susceptibility to Woolly Apple Aphid and/or Phytophthora cactorum as well as apple replant disease. The standard M.793 is too invigorating under new intensive planting systems and especially so for the newer strong growing scion cultivars. Very promising results have been obtained with some of the newly imported Cornell Geneva rootstocks regarding growth control and yield efficiency in a field trial established in 2000. When tree performance over the first three cropping years is considered, the most promising rootstocks appear to be CG 222 (M.9 vigour class), CG189 (M.7 vigour class), CG 228 and CG 007 (in the M.793 vigour class) and CG 778 (MM.109 vigour class).