Journal Article

Simulating the Influence of Vernalization, Photoperiod and Optimum Temperature on Wheat Developmental Rates

Gregory S. McMaster, Jeffrey W. White, L. A. Hunt, P. D. Jamieson, S. S. Dhillon and J. I. Ortiz-Monasterio

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 102, issue 4, pages 561-569
Published in print October 2008 | ISSN: 0305-7364
Published online July 2008 | e-ISSN: 1095-8290 | DOI: http://dx.doi.org/10.1093/aob/mcn115
Simulating the Influence of Vernalization, Photoperiod and Optimum Temperature on Wheat Developmental Rates

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  • Ecology and Conservation
  • Evolutionary Biology
  • Plant Sciences and Forestry

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Background and Aims

Accurately representing development is essential for applying crop simulations to investigate the effects of climate, genotypes or crop management. Development in wheat (Triticum aestivum, T. durum) is primarily driven by temperature, but affected by vernalization and photoperiod, and is often simulated by reducing thermal-time accumulation using vernalization or photoperiod factors or limiting accumulation when a lower optimum temperature (Toptl) is exceeded. In this study Toptl and methods for representing effects of vernalization and photoperiod on anthesis were examined using a range of planting dates and genotypes.

Methods

An examination was made of Toptl values of 15, 20, 25 and 50 °C, and either the most limiting or the multiplicative value of the vernalization and photoperiod development rate factors for simulating anthesis. Field data were from replicated trials at Ludhiana, Punjab, India with July through to December planting dates and seven cultivars varying in vernalization response.

Key Results

Simulations of anthesis were similar for Toptl values of 20, 25 and 50 °C, but a Toptl of 15 °C resulted in a consistent bias towards predicting anthesis late for early planting dates. Results for Toptl above 15 °C may have occurred because mean temperatures rarely exceeded 20 °C before anthesis for many planting dates. For cultivars having a strong vernalization response, anthesis was more accurately simulated when vernalization and photoperiod factors were multiplied rather than using the most limiting of the two factors.

Conclusions

Setting Toptl to a high value (30 °C) and multiplying the vernalization and photoperiod factors resulted in accurately simulating anthesis for a wide range of planting dates and genotypes. However, for environments where average temperatures exceed 20 °C for much of the pre-anthesis period, a lower Toptl (23 °C) might be appropriate. These results highlight the value of testing a model over a wide range of environments.

Keywords: Wheat; Triticum aestivum; T. durum; air temperature; thermal time; shoot apex; phenology; growth stages; anthesis; flowering

Journal Article.  5495 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

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