Early-growth results within a Eucalyptus globulus breeding population suggest limited scope for selection focused on CO2 responsiveness

Matthew Theodore Brookhouse, David Bush, Milos Ivkovich, Florian Busch, Graham Douglas Farquhar, Elizabeth Pinkard

Research output: Contribution to journalArticlepeer-review

3 Downloads (Pure)


Increasing [CO2] may influence commercial crop and timber yield. While selection of genotypes sensitive to elevated [CO2] (e[CO2]) appears possible in agricultural crops, there is limited evidence for genotype-by-CO2 (G × CO2) interactions in commercial tree species. We examined [CO 2] responsiveness in 124 open-pollinated Eucalyptus globulus ssp. globulus (E. globulus) families with the aim of assessing whether G × CO2 interactions are detectable in seedlings for early-age screening. Plants were grown in ambient (a[CO2]; ~ 405 μmol mol−1) and e[CO 2] (640 μmol mol−1) and harvested 25 days after germination. Total, shoot, and root dry weights were determined for each plant. Carbon isotopic discrimination against 13C (Δ 13C) was determined at the family level. We observed highly significant (p < 0.0001) increases in mean total, shoot, and root dry weights. Mixed-model equations were used to estimate the main and interaction effects of the G × CO2 for each mass trait. The main effects from the mixed-model output ([CO2] and individual-tree effects) were significant for all traits. However, [CO2]-by-individual tree interactions were non-significant for all traits, indicating little G × CO2 interaction. A secondary aim was to examine the correlation between greenhouse and mature-age growth from breeding trials that use common families conducted under ambient [CO2]. These correlations were non-significant, suggesting early growth is not necessarily indicative of later-age responses. Our results suggest that while early growth of E. globulus is enhanced under e[CO2], genotypes respond relatively uniformly to e[CO2] and little opportunity exists for seedling-based selection at the population level based upon the response of plants during the first weeks of growth.

Original languageEnglish
Article number16
Number of pages14
JournalTree Genetics & Genomes
Issue number2
Early online date21 Mar 2022
Publication statusPublished - Apr 2022

Bibliographical note

Funding Information:
We wish to thank staff within the Australian National University’s Plant Service Division for their support in managing the experiment outlined in this paper. We also wish to thank Ms Victoria Allen, Mr Diego Marquez Antivilo, Dr Chandra Bellasio, Dr Ross Deans, Mr Peter Groeneveld, and Ms Zoe Groeneveld for their assistance in plant harvesting and Ms Nedelca Scharp, Dr Hilary Stuart-Williams, and Mr Haydon Siiteri for their assistance and support during weighing and measurement of stable isotopes. We also wish to acknowledge two anonymous reviewers for their insightful comments that improved the manuscript. Seed was generously provided by the Tree Breeding Association.

Open Access funding enabled and organized by CAUL and its Member Institutions This study was funded by a Science Industry Endowment Fund (SIEF; Project RP04-122) grant.

Publisher Copyright:
© 2022, The Author(s).


  • Carbon-isotope discrimination
  • Elevated CO
  • Eucalyptus
  • G × CO
  • REML

ASJC Scopus subject areas

  • Forestry
  • Molecular Biology
  • Genetics
  • Horticulture


Dive into the research topics of 'Early-growth results within a Eucalyptus globulus breeding population suggest limited scope for selection focused on CO2 responsiveness'. Together they form a unique fingerprint.

Cite this