Effects of elevated carbon dioxide and ozone on the growth and yield of spring wheat (<i>Triticum aestivum L</i>.)

Abstract

Spring wheat cv. Minaret was grown under three carbon dioxide (C0 2 ) and two ozone (O 3 ) concentrations from seedling emergence to maturity in open-top chambers. Under elevated CO 2 concentrations, the green leaf area index of the main shoot was increased, largely due to an increase in green leaf area duration. Biomass increased linearly in response to increasing CO 2 (ambient, 550 and 680 ppm). At anthesis, stem and ear dry weights and plant height were increased by up to 174%, 5% and 9 cm, respectively, and biomass at maturity was 23% greater in the 680 ppm treatment as compared to the ambient control. Grain numbers per spikelet and per ear were increased by 0.2 and 5 grains, respectively, and this, coupled with a higher number of ears bearing tillers, increased grain yield by up to 33%.