Understanding The Double Effect Of High Temperature On Crop Yield

GRDC - Victor Sadras, Mariano Cossani and Lachlan Lake (South Australian Research and Development Institute (SARDI)).

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

The authors of this paper note in the conclusion: "Crop establishment is of course important – we don’t want patchy stands. Likewise, grain filling is important – we don’t want small grain and screenings. However, grain yield is mostly correlated with grain number, and grain number is most sensitive to stresses in the crop-specific periods – before flowering in cereals, and after flowering in pulses and canola. Consequently, management for high yield should seek: a) long duration of the critical window (mild temperature), (b) high crop growth rate (for example, good nutrient supply), and (c) low risk of frost and heat during the critical window." Please access the full paper via the link below if this research interests you.

The take home messages from this GRDC funded research are below. Please access the full paper via the link below for methodology, references, acknowledgements and discussion.

Take key messages from the paper include:

  • Crop yield is a primary function of grain number per unit area; grain weight is secondary.
  • Grain number is defined in a crop-specific critical period. The most critical stage is shortly before flowering in cereals, and shortly after flowering in pulses and canola.
  • There are two distinct effects of elevated temperature. First, elevated non-stressful temperature that shortens the critical period, hence reducing grain number and yield; for example, 1oC increase in mean temperature in critical period of wheat in South Australia (SA) reduces yield by 0.2 to 0.6t/ha. Second, elevated stressful temperature that causes sterility; stressful temperatures are low 30oCs for cereals and low to mid-30oCs for pulses.
  • Focus on growth and stress avoidance during critical period for grain set.

2020 - Australia - GRDC - Victor Sadras, Mariano Cossani and Lachlan Lake (South Australian Research and Development Institute (SARDI)).
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