Genetic Parameters and Gain Estimates for Growth Traits in Chir Pine (Pinus Roxburghii Sarg.) in a 22 Years Old Half-Sib Progeny Test

Abstract

Twenty two year old half-sib progenies of 58 plus trees of Chir pine (Pinus roxburghii Sarg.) grown in a progeny test at Solan, Himachal Pradesh, India, were evaluated. The estimated test mean for tree height and dbh was 12.43 m and 21.37 cm with current annual increment 0.93 m and 1.31 cm, respectively. Family mean for tree height varied from 8.04 m to 16.08 m and for dbh from 14.56 cm to 27.23 cm. The family differences were highly significant (P<0.001). Tree-to-tree variance within plot (σ²w) was the major contributor (more than 78%) towards the total phenotypic variance for all the growth traits studied. Narrow sense heritability of family means (h²f) ranged from 0.514 to 0.443 and was consistently higher than that calculated on individual tree basis (h²i) for each growth traits. A genetic gain of 13.37% in height growth and 12.04% in dbh at age 22 years is expected to be realized by selecting best 30% (18 out of 58) of families in combination with retaining best five of total ten trees in each family plot (50% selection intensity at within-family level) of these selected families.