Adverse high temperature effects on pollen viability, seed-set, seed yield and harvest index of grain-sorghum [Sorghum bicolor (L.) Moench] are more severe at elevated carbon dioxide due to higher tissue temperatures

Summary

This controlled-environment study demonstrates that elevated CO₂ concentration (700 μmol mol⁻¹) exacerbates the adverse effects of high temperature on grain-sorghum reproduction and yield compared to ambient CO₂ (350 μmol mol⁻¹). Whilst elevated CO₂ increased seed yield by 26% at optimal temperatures (32/22 °C), this benefit was reversed at elevated temperatures, with decreases in pollen viability, seed-set and harvest index at high CO₂ being more severe than at ambient CO₂. The researchers attribute this temperature sensitivity to higher canopy and seed temperatures under elevated CO₂.

Regional applicability

Although the study was conducted in controlled environments rather than UK field conditions, the findings are relevant to understanding climate change impacts on sorghum production globally. UK cultivation of grain-sorghum is limited by climate, but the mechanistic insights into CO₂–temperature interactions may inform crop breeding and adaptation strategies as temperatures rise in temperate regions.

Key measures

Pollen viability, pollen production, panicle emergence, seed-set, seed yield, harvest index, canopy foliage temperature, seed temperature

Outcomes reported

The study measured pollen viability, pollen production, seed-set, seed yield, harvest index, and panicle emergence in grain-sorghum under combined temperature and CO₂ treatments. It quantified how elevated CO₂ exacerbates the negative reproductive and yield impacts of high temperature stress.

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