Carbon dioxide and temperature interactions on stem extension, node initiation, and fruiting in cotton

Abstract

Understanding the response of agricultural crops to rising carbon dioxide concentration (CO 2) and temperature is critical for modeling the effects of future climate change on crop productivity. The objective of this study was to evaluate the direct and interactive effects of temperature and CO 2 on mainstem and branch expansion rates, node initiation rates, and fruiting in cotton to be used for the development of a cotton simulation model. Cotton plants ( Gossypium hirsutum L., cv. DPL 50) were grown in plant growth chambers exposed to natural light levels with temperature and CO 2 as treatments. The average temperatures were 17.8, 18.7, 22.7, 26.6, and 30.6°C during a 70 day experimental period with CO 2 treatments of 350 and 700 μl l −1 at each temperature. Plant height and number of mainstem nodes increased with increase in temperature and CO 2. A nine-fold increase was observed in number of fruiting branches with increase in temperature from 17.8 to 30.6°C, however, no significant differences were observed in fruiting branch number due to doubling of CO 2 except at 30.6°C. The number of days from emergence to first square was strongly influenced by temperature, and CO 2 had no effect on this process. The number of squares and bolls were increased at higher temperatures, and the rate of increase was greater at 700 μl l −1 CO 2.