GENETIC PARAMETERS OF <em>GMELINA</em> <em>ARBOREA</em> : HEIGHT AND DIAMETER GROWTH

Abstract

An open-pollinated progeny trial from 36 plus trees of Gmelina arborea was established using randomized complete block design (RCBD). Individual tree height (Ht) and diameter at breast height (DBH) were measured annually. Narrow sense heritability (h²_u), phenotypic (τ_P) and genotypic (τ) correlations, and genetic gain (▲G) were estimated for Ht and DBH from age one to six and age three to six years respectively. Heritability values for Ht ranged from 0.07 to 0.17 while for DBH, it was about to 0.12. The values for both traits were very low indicating a very low degree of inheritance. τ_p and τ_G between Ht and DBH at year one to six were strong (> 0.5), indicating that early selection for these traits would be effective. Expected ▲G for Ht and DBH were 0.221 m and 0.456 cm respectively. The gains represented an improvementof4.4% (Ht) and 8.6% (DBH) over the base population. It is suggested that low intensity mass selection followed by high intensity family selection could be carried out to warrant good response in ▲G.