Performance and genetics of provenance hybrids of Pinus caribaea var. hondurensis in Queensland

Two control-pollinated inter-provenance hybrids made between selected trees in the improved Mountain Pine Ridge (MPR) provenance, and selected trees in both Coastal and Guanaja Island provenances of Pinus caribaea var. hondurensis were evaluated along with a control (open-pollinated MPR provenance) at two Queensland sites (Tuan and Cardwell) to 6 - 7 years of age for growth, and stem and crown quality. Control-pollinated families of Coastal provenances were also planted in these tests. The major objective of provenance hybridisation was to incorporate desirable and complementary attributes of Coastal and Guanaja germplasm into the advanced breeding population of P. caribaea var. hondurensis in Queensland, which is composed primarily of trees from the MPR provenance. At both the individual sites and across the two sites, the inter-provenance hybrid MPR × Coastal had greater diameter, stem-straightness and wind-firmness, and fewer ramicorns than the MPR control provenance. This hybrid showed significant mid-parent heterosis for these same traits, and ranked better than the high-parental values.Submitted in fulfillment of the requirements of the degree of Masters of Science by Research, University of the Sunshine Coast, 2001