Prognosis and correction of iron chlorosis in peach trees and relationship between iron concentration and Brown Rot

This study investigates the possible correlations between bark, floral, and leaf iron (Fe) concentrations and SPAD measures to be used as early methods for prognosis of iron chlorosis in peach trees. The results showed that there were significant correlations between bark, floral and leaf Fe concentrations and SPAD measurements. This study shows for the first time the possibility Of using bark analysis as an early predictive method of iron chlorosis in peach trees. Differences in mineral composition of leaves of peach trees, in relation to rootstocks were also found. This study also investigated the distribution of mineral elements in different parts of peach leaves. Tissue analysis of different leaf parts showed that the peripheral and petiole of leaves had the highest P, Ca, Mg, Zn, Fe, B and Cu concentrations. In contrast, the highest K concentration was found in the internal parts of leaves. High Mn concentration was found in the laminar of leaves, but was lower in the petioles. In other experiments, the effect of different sources of Fe application on the leaf Fe concentrations and development of Brown Rot in the year of application and one and 2 years later was also examined. No application increased significantly the leaf Fe concentrations in the year of application and 1 year later. Leaf Fe concentrations were significant higher in trees treated with FeSO4 center dot 7H(2)O + S 2 years after application. The possible effect of flesh Fe concentration to susceptibility of peach (cv. Sun Crest) to Monilinia laxa was also evaluated. The results showed no correlation between flesh Fe concentration and Susceptibility of peach to M. laxa. Besides, no statistical difference was found in the Susceptibility of peach to M. laxa collected from the cultivar Sun Crest grafted on different rootstocks. (C) 2008 Elsevier B.V. All rights reserved.