Estimates of Genetic Variability and Correlation in Eucalyptus Hybrid Progeny For Early Selection

A trial of progeny of 11 Candidate Plus Trees (CPTs), 2 sources of clonally propagated planting material and one source of clonal seed orchard seedlings was conducted at Thathlan, Hoshairpur (Punjab) to assess the growth performance and to evaluate genetic variability and correlation among different growth characters for three consecutive years. In all quantitative characters assessed, clonal material viz. T₉, T₁ and T₁₀ gave the best height, diameter and clean bole. The heritability values for height (0.67 to 0.71), diameter (0.50-0.59) and clean bole (0.64-0.76) were high with high genetic gains upto three year of observations. The findings suggest that these characters are governed by the genetic make up of the trait and attribute significantly to the phenotypic performance at early stage giving ample opportunity for selection of the outstanding genotypes. Similarly, straightness exhibited high heritability varying from 0.55 to 0.64 during the first and third year respectively. The heritability estimate for axis persistence ranged from 0.46 to 0.56 with high genetic gain of 21.10 to 14.63 in year one and three respectively. The significant genotypic and phenotypic correlation found between height and diameter suggests that improvement in one character will be accompanied by another. Also a high positive significant correlation was exhibited in year one to three. A highly significant age-age correlation for height and diameter growth indicate that selection based on these two characters can be done at the juvenile stage to achieve more gain per unit time.