Calcium, Iron and Boron Contents of Nursery-Produced Trees Affect Long-Term Orchard Productivity of Apples

High initial investment costs of an orchard generate the need for higher productivity in the first years of its life. Various nursery techniques have been proposed for obtaining high-quality nursery trees to accelerate the early high yield of apples. However, there is no detailed study on which nursery tree attributes determine orchard productivity, especially for spur-type apple cultivars. This study firstly aimed to reveal the features of two types of planting material, namely 1- and 2-year-old nursery trees. Secondly, it aimed to reveal which morphological and physiological nursery tree attributes affect productivity in a significant lifetime of the orchard in both narrow (1 m) and wide (2 m) tree spacings. The study was conducted at the Fruit Research Institute located in the Mediterranean area of Turkey. In this study, two successive trials, one in the nursery during two growing seasons (2009-2010) and the subsequent trial in the orchard over 6 years (2011-2016), were conducted in spur-type 'Red Delicious' apple on 'MM.106' rootstock. In the nursery, 2-year-old trees had significantly higher values for the number of branches, trunk cross-sectional area, tree height, total leaf area and Soil Plant Analysis Development index than 1-year-old nursery trees. Using 2-year-old nursery trees significantly increased the yield, especially at 1 m tree spacing. The number of branches, calcium, iron and boron contents in the leaves of nursery-produced trees significantly promoted productivity in the apple orchard.