Assessment of variability in morphological and wood quality traits in Melia dubia Cav. for selection of superior trees

Abstract

Assessment of natural variability in morphological and important wood quality traits and selection of trees with superior or desired wood characteristics is a prerequisite for an effective tree improvement. Variability in morphological and wood quality traits was assessed in selected trees from a 9-year-old plantation of Melia dubia raised from material of unknown genetic source. A large variation was observed in vertical and lateral tree growth within the sampled trees. Wood quality traits namely heartwood proportion, basic density, stress wave velocity, dynamic modulus of elasticity (DMoE) and volumetric shrinkage also exhibited a substantial variation between trees. Pilodyn penetration exhibited a strong negative correlation with wood basic density and DMoE. Acoustic velocity in trees, wood basic density, and volumetric shrinkage did not exhibit any significant relationship with each other. Similarly, tree growth parameters were not related to either wood density or shrinkage. Acoustic velocity measured in standing trees by transit-time method was in a close agreement with the velocity measured in logs using resonance method. A large variability in the measured traits and absence of any significant relationship in morphological and wood quality traits imply that selection of trees with superior wood properties can be made for further propagation without compromising on tree growth. Pilodyn and acoustic velocity measurements in standing trees provided an opportunity to screen and select M. dubia trees with superior wood density and modulus of elasticity.