Sample size is critical when exploring the grain set in wheat cultivars grown under frost-prone field conditions in Western Australia

Brenton Leske1, Ben Biddulph2, Mario D’Antuono2, Ifeyinwa Olive Onyemaobi2 and Timothy Colmer

1 University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Department of Primary Industries and Regional Development, 3 Baron-Hay Court, South Perth, WA 6151


Quantifying the grain set and floret sterility (FS) of wheat cultivars is crucial to benchmarking their susceptibility to frost and exploring cultivar differences so that genetic improvement can be made. Ensuring that the measurement of grain set and FS is accurate and adequately captures the variation within and between spikes and cultivars, is vital to making progress in this space. A field trial with eight times of sowing blocks (from mid-April to early-June) was established at Dale, Western Australia to evaluate the susceptibility to frost of 15 wheat cultivars, of which three are reported on in this paper. Variance component analysis was used to determine the optimal sample size from a sub-set of three wheat cultivars with known differences in their susceptibility to frost damage (Impose CL Plus, Kunjin and Magenta). The optimal sample size was determined to be 15 to 20 spikes per plot, when grain positions per spike ranged from 25 to 35.. Future phenotyping experiments exploring stresses or traits related to spike fertility would benefit from undertaking a variance component analysis to ensure efficient use of their resources.



The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography Graham Centre for Agricultural Innovation, Charles Sturt University

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