EARLY PERFORMANCE OF 4 APPLE CULTIVARS ON MARK AND OTHER ROOTSTOCKS IN MAINE

In 1985, a study was established to compare the growth and fruiting of 'Cortland', 'Empire', 'Delicious' and 'McIntosh' apple (Malus domestica Borkh.) on Mark and MM.111 rootstocks. 'Delicious' and 'McIntosh' on M7A and M.26 were also included. Tree survival for the first six years was 90% or greater for all combinations except' Empire'/MM.111, 30% of which died as a result of winter injury. Burrknots occurred on all cultivar/rootstock combinations, with the fewest on 'Mclntosh'/MM.111. Early flowering was greatest with 'Empire' and 'McIntosh' on Mark. M.26 also induced early flowering, while M.7A induced early flowering with 'Delicious' but not with 'Mclntosh'. Cumulative yield was highest with 'Mclntosh on Mark and M.26 and with 'Cortland'/Mark. The lowest cumulative yields were recorded for Empire'/MM.111 and for 'Delicious' regardless of rootstock. Tree leaning was severe for trees on Mark or M.26, and growth proliferations at the soil line were observed on all cultivar Mark combinations.