Post-anthesis warm nights reduce grain weight in field-grown wheat and barley

• Published in: Field crops research Vol. 195; pp. 50 - 59
• Main Authors: García, Guillermo A., Serrago, Román A., Dreccer, M. Fernanda, Miralles, Daniel J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-08-2016
• Subjects: adverse effects; barley; carbohydrates; Climate change; crops; EGFP; filling period; flowering; FPAR; GFD; GFR; Grain filling duration; Grain weight; grain yield; growing season; heat; Hordeum vulgare; malting barley; middayFPAR; Minimum temperature; night temperature; PAR; phenology; sowing; Temperate cereals; Triticum aestivum; wheat; PAR; GW; Climate change; GFR; Grain filling duration; Temperate cereals; GFD; middayFPAR; Grain weight; Minimum temperature; FPAR; EGFP
• ISSN: 0378-4290; 1872-6852
• DOI: 10.1016/j.fcr.2016.06.002

•Wheat and barley response to post-anthesis warm nights was evaluated under field conditions.•Grain weight was reduced by 3% per °C of night temperature increase, causing a yield reduction of 4% per °C.•Grain weight response to post-anthesis warm nights was strongly driven by the developmental rate.•An accelerated development under high night temperatures led to a shorter effective grain filling period.
Wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) crops are exposed to warm nights during their growing seasons and this trend is unlikely to change. The aim of this work was to evaluate the effect of higher post-anthesis night temperatures on field-grown crop yield, focusing on final grain weight determination. Experiments combined: (i) two well-adapted crops with similar phenology: bread wheat and two-row malting barley, under (ii) two temperature regimes: ambient and high night temperatures from 10days after anthesis to physiological maturity during (iii) two contrasting growing seasons in terms of radiation and temperature: late sowing in 2011 and early sowing in 2013. The night temperature increase (ca. 4.1°C) was achieved using purpose-built heating chambers placed on the crop at 7pm and removed at 7am every day during the heating period. Across growing seasons and crops, the average minimum temperature during that period ranged from 14.3°C to 21.9°C. Thousand grain weight was reduced by ca. 3% per °C of night temperature increase, similarly for wheat and barley, causing a grain yield reduction of ca. 4% per °C. An accelerated development under high night temperatures led to a shorter effective grain filling period, reducing the final grain weight. The lack of consistent impact on source availability between crops and seasons, measured as senescence and stem water soluble carbohydrates, as well as a similar impact in magnitude and direction on individual grain weight for different grain positions along wheat or barley spikes, suggest that the negative effects of warm nights on grain weight were directly related to processes within the grain itself.