Abstract:

Elevated CO₂ concentrations and temperatures under global climate change scenarios projected for coming decades could impact bread wheat (Triticum aestivum) quality. Hence, there is a need to understand the effects of these environmental factors on crop quality. The objective of this study was to experimentally test the effects of elevated CO₂, temperature, and their interactions on wheat grain quality characteristics relevant to its processing, including grain protein content, wet gluten content, sedimentation value, and falling number (alpha-amylase activity). Bread wheat ('Liaochun 10') was field grown in CO₂ and temperature gradient chamber (CTGC) and ambient controlled temperature gradient chamber (TGC). The results indicated that elevated CO₂ concentrations (433.3 to 610.2 μmol·mol^-1) had negative effects on grain protein content, wet gluten content and sedimentation value of bread wheat, but gradual temperature increases (2 ℃ range) had positive effects on these three main quality characteristics. The interaction between gradual increases in CO₂ levels from 433.3 to 551.5 μmol·mol^-1 and temperature increases (+2 ℃ range) showed a similar benefit on grain protein content, wet gluten content and sedimentation value of bread wheat, but when CO₂ concentrations approached 610.2 μmol·mol^-1 and mean daytime temperature increased more than 2 ℃, the interaction of CO₂ and temperature had a negative effect on the three bread wheat quality characteristics. In addition, under CO₂ concentrations of 433.3-610.2 μmol·mol^-1 and gradually increasing temperatures, CO₂ enrichment reduced alpha-amylase activity of bread wheat whereas elevated temperatures and the interaction of elevated CO₂ and temperature enhanced alpha-amylase activity of bread wheat.

Key words: Elevated CO₂, Temperature, Bread wheat, Quality characteristics, CO₂ and temperature gradient chamber (CTGC), Global climate change