The performance of the apple cultivar Delicious on Merton and other clonal rootstocks in southern Queensland

Abstract

Final results are reported of the performance of the Delicious apple on rootstocks Merton 778, Merton 779, Merton 789, Merton 793, Northern Spy, local selection S4, and its own roots planted under wide spaced dryland conditions on 2 soil types on the Granite Belt. Rootstocks interacted with soil types for trunk girth and yield, and results are discussed in this context. Largest and smallest tree girths on both soil types were produced by S4 and Northern Spy, respectively. Large differences in girth occurred between soil types for all rootstocks except Merton 779. Highest accumulated yields on the more fertile soil were produced by Merton 778, Merton 793 and Merton 779 in that order. Merton 779 gave highest yields on the poorer soil. Own roots, Merton 789 and Northern Spy yielded least on both soils. Two estimates of mean tree fruitfulness showed Northern Spy and Merton 793 to be the most fruitful and S4 the least. Northern Spy may be useful in high density hedgerow orchards where soil fertility is good. For wide-spaced, dryland management on variable and poor soil Merton 779 is recommended, while on fertile soil Merton 778 or Merton 793 is recommended.