Effects of Rootstocks and Microsprinkler Fertigation on Mineral Concentrations, Yield, and Fruit Color of ‘BC-2 Fuji’ Apple

Abstract

Mineral concentrations in shoot leaves, spur leaves, mixed-buds, and fruit tissue, and yield, and fruit color of ‘BC-2 Fuji’ apple ( Malus domesticaBorkh.) trees as affected by five rootstocks, B.9, M.9 NAKBT337, O.3, M.26 EMLA, and M.7 EMLA, and five nutrition treatments, applied through a microsprinkler system, were evaluated during 1998 and 1999. Nutrient treatments were 22.4 kg N/ha (low N), 89.7 kg N/ha (medium N), 156.9 kg N/ha (high N), 89.7 kg N/ha plus 78.5 kg K/ha (medium N + K), and 156.9 kg N/ha plus 78.5 kg K/ha (high N + K). Trees on B.9 had lower K and higher Ca in the shoot and spur leaves, and had higher fruit Ca than other rootstocks in both years. Shoot and spur leaves, and fruit tissues of trees on M.7 EMLA had significantly higher K concentrations than those on other rootstocks. Shoot leaves and mixed-buds of trees on M.26 EMLA had higher Mg concentrations than trees on most other rootstocks during the two years. Fruits of trees on B.9 had significantly higher Ca and Zn concentrations than those on other rootstocks during both years. Trees on B.9 were more yield efficient (yield/trunk cross-sectional area) than those on M.26 EMLA and M.7 EMLA in both years. Trees receiving low N had lower N but higher K concentrations in all tested tissues, except in mixed-buds, compared to trees in other nutrient treatments. Fruits from trees with low N had better color than those from trees receiving higher N. Addition of K with N fertigation treatments had little effect on K concentrations of tree tissues.