Hardy framework influence (1969-1983) on yield, tree size and yield efficiency of Wellspur and Goldspur apple

Abstract Cumulative yield, trunk cross-sectional area, and yield efficiency were measured between 1969 and 1983 in an experimental planting (established in 1964 and top-worked in 1965) of ‘Wellspur’ and ‘Goldspur’ apple top-worked on frameworks of 19 cold-hardy cultivars (‘Alnarp 2’, ‘Antonovka’, ‘Beacon’, ‘Canada Baldwin’, ‘Delcon’, ‘Dr. Bill’, ‘Duchess’, ‘Haralson’, ‘Hawkeye Greening’, ‘Heyer 12’, ‘Heyer 20’, ‘J. Luke Seedling’, ‘McIntosh’, ‘Minnesota 447’, ‘Ottawa 271’, ‘Ottawa 292’, ‘Red Astrachan’, ‘Robusta 5’, ‘Yellow Transparent’) that were grafted on domestic seedling roots. There were significant differences in yield, trunk diameter and yield efficiency related to the interstock. ‘Duchess’ and ‘Heyer 12’ ranked highest in yield efficiency and lowest in tree size. ‘Red Astrachan’ ranked lowest in efficiency and largest in tree size. ‘McIntosh’ also tended to be low in efficiency. No severe winter temperatures occurred to test differential cold hardiness.