Intraspecific hybridization in Pinus caribaea var. hondurensis II. Genetic parameters

Genetic parameters of growth and stem straightness to seven years of age were estimated from two field populations of pure Pinus caribaea var. hondurensis provenances and their intraspecific hybrids, (Mountain Pine Ridge (MPR) × coastal provenances). There were no consistent differences in the genetic parameter estimates obtained for the parental provenances compared to those from the MPR × coastal inter-provenance hybrid crosses. Narrow-sense heritabilities of growth traits (0.06–0.33) and straightness (0.21–0.50) were within the range of estimates that have been previously reported for this species and other tropical pines. In general, additive variance was found to be more important than dominance variance for growth and straightness traits. There was no strong evidence to affirm that the superiority of the MPR × coastal hybrid could be caused by dominance variance. The low magnitude of the type-B genetic correlations within the MPR × coastal hybrid crosses suggested that the genotype-by-environment interaction might be of practical importance in breeding. For future hybridization of the MPR and coastal provenances, a recurrent selection scheme based on the utilization of additive genetic variance of both parent populations is recommended.