Prognosis of iron chlorosis in pear (Pyrus communis L.) and peach (Prunus persica L. Batsch) trees using bud, flower and leaf mineral concentrations

Abstract

Background and Aims The possibility of using tree materials in early phenological stages, such as dormant buds and flowers, for the prognosis of Fe deficiency occurring later in the year has been studied in peach and pear trees. Methods Thirty-two peach trees and thirty pear trees with different Fe chlorosis degrees were sampled in different commercial orchards. In peach, samples included flower buds, vegetative buds, bud wood, flowers and leaves at 60 and 120 days after full bloom (DAFB). In pear, samples included buds, bud wood, flowers and leaves at 60 and 120 days DAFB. Leaf chlorophyll was assessed (SPAD) at 60 and 120 DAFB. Sampling was repeated for 3–5 years depending on the materials. Mineral nutrients measured were N, P, K, Ca, Mg, Fe, Mn, Zn and Cu. Results The relationships between the nutrient concentrations in the different materials and leaf SPAD were assessed using four different statistical approaches: i) comparison of means depending on the chlorosis level, ii) correlation analysis, iii) principal component analysis, and iv) stepwise multiple regression. In all cases, significant associations between nutrients and SPAD were found. The best-fit multiple regression curves obtained for the multi-year data set provided good prediction in individual years. Conclusions Results found indicate that it is possible to carry out the prognosis of Fe chlorosis using early materials such as buds and flowers. The relationships obtained were different from those obtained in previous studies using a single orchard. The different methods of analysis used provided complementary data.