Genetic parameters for growth, stem straightness, and branch quality for Pinus elliottii var. elliottii × Pinus caribaea var. hondurensis F1 Hybrid in Argentina

Abstract

Genetic parameters for growth, stem straightness, and branch quality were estimated in five progeny trials of Pinus elliottii var. elliottii (PEE) × Pinus caribaea var. hondurensis (PCH) F1 hybrid measured at ages three, five, and seven years. The trials comprised 133 full-sib families from the tree breeding program initiated by the National Institute of Agricultural Technology. Single-site analyses showed that the average individual-tree narrow- and broad-sense heritability estimates were respectively 0.24 and 0.53 for diameter and 0.34 and 0.47 for total height. Average estimated heritabilities were low to moderate for stem straightness (< 0.18), branch diameter (< 0.26), and branch angle (from 0.28 to 0.33). Bivariate analyses showed that the estimated additive and family genetic correlations between diameter and height were consistently high and positive (> 0.84). However, genetic correlations between growth variables and stem straightness, branch diameter, and branch angle were not significant in general. The average estimated additive genetic correlation between sites was high for growth trait and stem straightness (> 0.70), while for branch diameter and angle, the correlations between sites ranged from 0.19 to 0.99. The implications of these results for genetic improvement strategies based on PEE × PCH F1 hybrid in Argentina are discussed.