Growth and Performance of Four Apple Cultivars on M.26 and Mark Rootstocks, With or Without Preplant Mineral Nutrients

Abstract

To evaluate the interactions between cultivar and rootstock, four apple ( Malus domestica, Borkh.) cultivars, 'Pioneer Mac,' 'Marshall Mc-Intosh,' 'Ginger Gold' and 'Empire' on two rootstocks, M.26 and Mark, were planted in a splitplot design. After five years, 'Pioneer Mac' and 'Ginger Gold' had larger trunk cross-sectional area (TCSA) on M.26 than on Mark. 'Marshall Mclntosh' and 'Empire' had larger TCSA on Mark than on M.26. Precocity, expressed as both number of flower clusters and yield was greater for trees on Mark for all cultivars except for 'Ginger Gold,' which had greater flower cluster numbers and yield on M.26. Fruit size was variable from year to year, depending on crop load, however 'Pioneer Mac' and 'Ginger Gold' usually produced the largest fruit, while 'Empire' consistently produced the smallest fruit, 'Ginger Gold' appears to be incompatible with Mark. The results of this study demonstrate that cultivar x rootstock interactions can be significant and need to be considered when rootstock and planting density recommendations are made.