Phenotypic plasticity of leaf length to an environmental gradient in Khaya ivorensis (Meliaceae) populations in Ghana

Abstract

Khaya ivorensis encountears different ecological conditions in its native habitats in Ghana. The demand for this species has led to severe depletion of the natural stand, thus threatened with extinction. To address the dwindling populations demands intervention for restoration and establishment of plantations. The goal of reforestation is to establish a new generation of trees with optimal growth and adaptedness. Doing this requires knowledge of relative level of plastic response to environmental variables to aid general seed transfer which could be implemented by forest managers. In this study we employed Environmental Standardized Plasticity index (EPSI) and one-way ANOVA to understand the level of phenotypic plasticity in leaflet morphology to environmental gradient. Highly significant (P<0.0001) plastic response in leaf length was observed among the populations in relation to precipitation, temperature, altitude and latitude. The results suggested South-North clinal relationship to leaf length. The observed clinal variation in leaf length with environmental variables provide suitable framework for matching each provenance site or population to designate ecological zone, under premise each population has adapted to the local environmental conditions.

Key words: Clinal variation, Khaya ivorensis, climate change.