Influence of Rootstock on Fruit and Tree Characteristics of ‘Macspur McIntosh’

Abstract

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