Effect of Citrus Rootstocks on Root Distribution and Leaf Mineral Content of ‘Orlando’ Tangelo Trees1

Abstract

Abstract The effect of rootstock on tree size, root distribution and leaf mineral content of ‘Orlando’ tangelos on 11 rootstocks was studied. Pronounced differences in depth of rooting, weight of feeder roots and tree height were detected. Depth of rooting was correlated to tree height, (r = .58, 1970; r = .83, 1971) i.e., the tallest trees had the deepest root systems. Feeder root wt and tree height were not related. The level of leaf N, K, Ca and Mg but not P was related to rootstock, suggesting a differential absorption of mineral nutrients by rootstock. The level of N appeared to be influenced by root distribution. Trees with deep extensive root systems or with a large number of feeder roots near the surface had high leaf N. Leaf K was significantly correlated with depth of rooting, (r = .96, 1970; r = .84, 1971). The results suggested the maximum performance of all rootstocks was not attained under the uniform cultural conditions of this experiment and therefore the need to examine each rootstock under conditions optimum for it.