Western Iowa 1992 Apple Cultivar x Rootstock Trial
To better serve the commercial apple industry in western Iowa, a cultivar by rootstock study was established at the Western Iowa Research Farm in 1992. The trail is evaluating the performance of three apple cultivars (Smoothee Golden Delicious, Empire, and Nured Jonathan) on seven commercially available rootstocks (seedling, MM.111, MM.106, M.7 EMLA, M.26 EMLA, M.9 EMLA, and Mark) trained to a central leader system. Due to the differences in size-control potential of the rootstocks, trees on seedling, MM.111 and MM.106 were planted at an in-row spacing of 16 ft and were not staked. Trees on M.7 EMLA, M.26 EMLA, M.9 EMLA, and Mark were spaced 12 ft apart in the rows and were supported with a wooden stake. Large and small trees were maintained in separate rows. Between-row spacing was established to allow for 8 ft of clearance between rows (24 ft between rows of large trees, 22 ft between large and small trees, and 20 ft between rows of small trees). Each cultivar/rootstock combination was replicated 10 times in a split-plot arrangement of randomized complete block design with cultivar whole-plots and rootstock sub-plots. Cultivar and rootstock performance has been reported in the 1994 through 1999 Annual Fruit and Vegetable Progress Reports. This report summarizes the tree growth and yield characteristics for the 2000 growing season by cultivar and rootstock main effects.