Experience with some Pinus hybrids in Queensland, Austrlalia

Abstract

Hybridisation has been undertaken extensively in Queensland among and within several Pinus species with the aim of discovering and developing high-yielding varieties with suitable wood properties and matched to sites of industrial plantations. The plantations are located on a wide range of sites between 17°S and 27°S. The desired matching requires use of a number of taxa including hybrids. Currently the plantation area of Pinus elliottii var. elliottii × P. caribaea var. hondurensis (PEE × PCH) hybrids exceeds 26 000 ha (21% of the lowland, Pinus estate). Annual plantings of outcrossed F2 (best orchard families bulked) and selected
F1 families and clones exceed 3000 ha. Many other pine hybrids are under test.

This paper reviews the domestication of PEE, PCH and other taxa involved in hybridisation, the choice and development of the PEE × PCH F1 hybrid, and the exploration of a number of other hybrids. The production of PEE × PCH outcrossed F2 and the first backcross hybrids, and the potential of these and other hybrids locally and internationally are also reviewed. Possible future directions of pine hybrid breeding in Queensland and the main conclusions from the 40-year program, which has been intensive over the past 25 years, are indicated. It is suggested that “useful” hybrid vigour, in an industrial tree plantation program, is the economic (multi-trait) superiority of the hybrid over the higher-performing (high) parent.