Effect of elevated temperature and carbon dioxide on wheat (Triticum aestivum) productivity with and without weed interaction

Wheat (Triticum aestivum L.) crop is one of the most valuable crops, and further boost in wheat yields is essential to meet the food demand of the emerging world population. It is therefore necessary to know the influence of future climate change on wheat yields. Present investigation was conducted in temperature gradient tunnel (TGTs) to evaluate the effects of elevated temperature, CO2 concentration, weed and their interactions on grain, biological yield and other yield attributes (number of spikes/m(2), number of spikelets/spike, number of grains/spike and 1000-grain weight, harvest index) of wheat. Wheat crop was grown in TGT at three different temperature levels, i.e. T-1 ambient, T-2 ambient+1.5 degrees C, T-3 ambient+3 degrees C and two levels of carbon dioxide, i.e. ambient (ACO(2)) 400 ppm and elevated (ECO2) 550 +/- 50 ppm with and without weed interaction. The study revealed that yield and yield attributes of subsequent wheat crop increased due to ECO2. Mean individual effect of ECO2 increased grain yield of wheat by 14% and biological yield by 12% compared to ACO(2). On the contrary, the yield was decreased with elevated temperature where a decrease in the grain yield from -12% to -20% and biological yield from -11% to -18% was observed at 1.5 degrees C and 3 degrees C, respectively. Similarly the interaction of weeds in wheat crop, reduced the grain yield by 8% and biological yield of wheat by 6%, irrespective of CO2 and temperature levels. The statistical analysis (P<0.05) revealed significant effect of the interactions (CxT, CxW, WxT, and CxTxW) on yield. Overall results the study proposal to adapt an effective weeds management strategy to controlled conditions of yield of wheat crop under the controlled conditions of CO2 and temperature.