Growth, yield and quality of maize with elevated atmospheric carbon dioxide and temperature in north-west India

An experiment was conducted growing maize (Zea mays L.) in open top chambers (OTCs) to determine the effects of elevated atmospheric carbon dioxide (CO2) and temperature on growth, yield, yield attributes and grain quality of maize. Maize (var. PEHM 5) was grown with two levels of carbon dioxide i.e., ambient (400 ppm) and elevated (550 ± 20 ppm) and three levels of temperature i.e., ambient, ambient +1.5 °C and ambient +3.0 °C during kharif (July-October) seasons of 2013 and 2014 in New Delhi, India. Elevated CO2 increased grain yield of maize by 53.7% and harvest index (HI) by 2.9% compared to ambient CO2. Stover yield and yield attributes such as cob length, cob diameter, grain weight cob−1, number of grains cob−1 and 100 grain weight also increased with elevated CO2. However, elevated CO2 decreased N concentrations in grain by 11.0% and P content by 19.0% but increased K content by 5.0% over ambient CO2. Elevated temperature by 1.5 °C and 3.0 °C decreased grain yield by 4.9% and stover yield by 37.0% but increased HI by 6.0% compared to ambient temperature. Elevated temperature levels positively affected grain N, P and K concentrations in grain. Simultaneous elevation of CO2 and temperature increased leaf area index, number of grains row−1, grain yield and harvest index but decreased days to 50% tasseling, cob length, cob diameter, grain weight cob−1 and crude protein content in grain. Test weight, stover yield and total biomass increased at elevated CO2 with ambient +1.5 °C temperature but decreased at elevated CO2 with ambient +3.0 °C temperature. The results indicated that elevated CO2 had positive effects whereas elevated temperature had negative effects on growth and yield of maize. With elevation of both CO2 and temperature, elevated CO2 reduced the negative effects of elevated temperature on yield and yield components of maize.