Intraspecific hybridization in Pinus caribaea var. hondurensis I. Performance for growth and form traits

Inter-provenance hybrids of Pinus caribaea var. hondurensis were progeny tested in Queensland, Australia in order to assess the feasibility of incorporating some desirable traits into the local breeding population, consisting largely of a single upland provenance Mountain Pine Ridge (MPR). Data on phenotypic traits up to seven years from planting revealed that an inter-provenance hybrid, MPR × coastal had greater diameter, straightness and wind-firmness, and fewer ramicorns than the MPR control provenance. The data were mostly consistent for two widely separated sites, and also when pooled across those sites ( p <0.05). In addition, hybrid vigor for tree volume was apparent ( p < 0.05). Trees of coastal × Guanaja Island, and pure coastal provenances were as large as those of the MPR provenance but had fewer ramicorns. Even though the coastal ×Guanaja provenance seemed to produce trees that were more crooked than the MPR provenance, there was evidence at least within one site to suggest that the hybrid trees were superior in terms of wind-firmness ( p < 0.01). Breeding for hybrid vigor and pedigree selection of the priority hybrid, MPR × coastal are suggested as future measures. Pure provenance populations of coastal and Guanaja island are to be bred as sublines to the MPR breeding population for future use in inter-provenance hybridization and for gene conservation.