INFLUENCE OF ROOTSTOCK ON FRUIT AND TREE CHARACTERISTICS OF MACSPUR MCINTOSH

Macspur McIntosh apples grown on 4 rootstocks (M.9 EMLA, Ottawa 3, M.2 6 and M.4) were harvested at weekly intervals over a 5-6 week period a nd assessed for internal ethylene content (IEC), red skin colour, aver age fruit weight, flesh firmness, starch index (SI), soluble solids co ncentration (SSC), and titratable acidity. Data from the 4-year study showed no significant effect of rootstock on the proportion of fruit w ith an IEC of 1 ppm or more, a level indicative of fruit in the climac teric stage. Red skin colour, firmness, SSC, SI, and average fruit wei ght showed some differences in 1 or 2 years of the study but no trends were evident. Cumulative yield was not significantly different with r ootstock but tree canopies on M.9 EMLA and Ottawa 3 were smaller and m ore yield efficient than canopies on M.26 or M.4.