Paper Reviewed
Prakash, V., Dwivedi, S.K., Kumar, S., Mishra, J.S., Rao, K.K., Singh, S.S. and Bhatt, B.P. 2017. Effect of elevated CO2 and temperature on growth and yield of wheat grown in sub-humid climate of eastern Indo-Gangetic Plain (IGP). Mausam 68: 499-506.

Prakash et al. (2017) examined the combined effects of elevated CO2 and temperature on wheat production in an effort to understand how this important food crop might respond to changes in growing conditions that are anticipated for the future.

Wheat plants from two cultivars (DBW 14 and HD 2967) were grown outdoors in open-top chambers at the experimental farm of the ICAR Research Complex for Eastern Region, Patna, India, during the Rabi season of 2013-2014. The plants received adequate fertilizer and irrigation and were subjected to one of two temperature treatments (ambient and ambient + 1°C) and one of two CO2 levels (mean of approximately 335 and 477 ppm) during daylight hours.

In describing their findings, Prakash et al. report that grain yield and several yield attributes, including ear length, number of grains per ear, test weight, plant height and days to physiological maturity, all benefitted from elevated CO2, even at elevated temperatures. Grain yield, in particular, experienced respective CO2-induced increases of 52 and 44 percent in cultivars DBW 14 and HD 2967 under ambient temperatures, the magnitudes of which enhancements fell to 8 and 38 percent in the combined elevated temperature and elevated CO2 treatment (see Figure 1). Nevertheless, they were still enhancements!

Given their observations, Prakash et al. conclude that the "positive role of CO2 in enhancing photosynthesis of wheat is expected to counteract the negative effect of increase in temperature." And most individuals would consider that an encouraging outcome, especiallywhen it comes to meeting future food security needs.

Figure 1. Grain yields of two wheat genotypes in response to different CO2 and temperature treatments; T0C0 = ambient temperature and ambient CO2, T0C1 = ambient temperature and elevated CO2, T1C0 = elevated temperature and ambient CO2, T1C1 = elevated temperature and elevated CO2. Source: Prakash et al. (2017).