Estimation of Variability in Growth Characters of Forty Clones of Tectona gralvdis L.F.

Three and a half-year-old plants of 40 clones of Tectona grandis were quantitatively measured for plant height, collar diameter and survival per cent to assess the variability. Significant variations were recorded in all the three parameters studied. The extent of variations in growth parameters of height and collar diameter was large compared to survival per cent. Plant height and collar diameter gave comparable values for genotypic and phenotypic variations and coefficient of variation indicating that these parameters are under genetic control. Maximum heritability was observed for height (85.50%) followed by collar diameter (74.02%) compared to 23.07% in survival per cent. Both the growth attributes, i.e., height and collar diameter were found to be heritable and there is a scope for considerable genetic gain through selection. Plant height and collar diameter also recorded the higher genetic gains 46.63% and 36.83% respectively, indicating effectiveness of these parameters for selection of best individuals/ clones.