Response of weeds under elevated Co2 and temperature: A review

Abstract

Climate change refers to a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). Under changing climate, high temperature and elevated CO2 are predicted to increase in frequency, causing serious challenges to sustain global food security. Among the 86-plant species which supply most of the world's food, only five are C4 species. Among 18 most troublesome weeds in the world, 14 are C4 species. Most of troublesome weeds species are C4, while most major crops areC3photosynthetic pathway. Various studies revealed that both crops and weeds respond to changing climate scenario. Weeds comes under C3 pathway may dominate under elevated CO2 conditions, whereas in elevated temperature, C4 weeds may dominate. The interactive effect of elevated CO2 and temperature showed that C4 weeds dominate over C3 weeds. Crop-weed competition was low at elevated CO2 whereas high under elevated temperature. The interactive effect of elevated CO2 and temperature on crop-weed competition was high. Hence, weed management is considered as a major threat to future agriculture.