Genetic variation, heritability and correlations of agro-morphological traits in tall fescue (Festuca arundinacea Schreb.)

Abstract

To study the genetic variation, heritability and genetic correlations of some agro-morphological traits in tall fescue, 25 parents from a genetically broad-base germplasm were polycrossed and their respective half-sib families were generated. Clonally propagated parents and their half-sib families were grown as spaced single plants using a randomized complete-block design with three replications, and observed for seven traits in 2006 and 2007. The estimates of broad-sense heritability $\left( {h^{2}_{\text{n}} } \right)$ were moderate to high $\left( {h^{2}_{\text{b}} \, = \, 0.43\, - \,0.80} \right)$ for the traits studied. Narrow-sense heritability $\left( {h^{2}_{\text{n}} } \right)$ estimates from analyses of progenies and from regression of half-sib (HS) progenies on parents $\left( {h^{2}_{\text{op}} } \right)$ suggested that genetic variation for these traits was largely controlled by additive gene action. Association of dry matter yield (DMY) with plant height, number of fertile shoot, curbs width and spring growth was positive and significant. With the exception of number of days to pollination, correlation coefficients of the traits between the parents and offspring were not significant. Based on parent-offspring regression, genetic gain from selection for DMY was high, demonstrating genetic potential for improving this trait. Overall, there was high genetic variation and moderate heritability for most traits in the tall fescue populations evaluated. In conclusion, to improve herbage yield, selection would be more effective based on forage yield components.