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Genetic analysis of Eucalyptus fastigata progeny trials and implications to selection

By Mari Suontama, Mark Miller, Kane Fleet, Toby Stovold and Heidi Dungey, June 2018.

Download SWP-T050 (pdf)

Executive summary

Progeny trials for Eucalyptus fastigata in the third cycle, planted in 2009 and 2010 in Kaingaroa and Waihaha were assessed in 2012-2013 for growth, form and adaptability. These trials are now advanced to the age where selections for the next generation can be made and due to forest management requirements in Kaingaroa, it is necessary to collect measurements for selection purposes prior to the thinning.

The objective of this milestone was to first assess trees at Kaingaroa for growth, form and wood stiffness and at Waihaha for growth, form, and foliar health. Following phenotypic assessment, genetic analyses were conducted for estimation of genetic variation and covariation, and to identify any genotype by environment interaction across sites. Finally a list of breeding values for selection of next generation seed orchard and breeding population individuals were produced.

Results from this study indicate that there is great potential for genetic improvement of productivity and tree form in the E. fastigata breeding population. Wood stiffness was measured for the first time in this breeding population, with an average modulus of elasticity of ~12 GPA (MOE in gigapascal) and a moderate estimate of heritability. Genetic correlations between the traits and between the different ages showed that some highly correlated traits can be replaced by one another if there is a requirement for more efficient assessment scheme. Due to the seed introductions from South African and Australian seed sources along each breeding cycle, provenance/seed source variation is still considerable for form traits and should be taken into account in selections.

Selection and marking of trees to remain post-thinning can now be progressed during 2018-19.

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