Model-based Approach to Study the Response of Bt-cotton Towards Elevated Temperature and Carbon Dioxide in the Semi-arid Region of Hisar

Cotton is one of the principal commercial fibercrop. India is highest in terms of agricultural land involved in cotton production but second highest in production. Decadal yield data reveals that its productivity is 243 kg/ha lesser than the global average. Weather aberrations is one of the paramount reasons for the productivity loss. The present study aims at estimating the implications of increasing temperature and CO₂ concentrations on cotton yield using a crop model DSSAT. Three different Bt-cotton varieties Pancham-541, RCH-791 and SP-7007 are considered for the study with three sowing dates 10th May, 21st May and 6th June. For Pancham-541 variety, rise in 1°C of temperature with 50 ppm CO₂ is beneficial, but further rise is harmful. Whereas for RCH-791 and SP-7007, productivity decreases gradually with increasing temperature and CO₂. Generally, yield decreases with increase in temperature (by 1°C), but no significant effect observed with increasing CO₂ (50 ppm) cumulatively. The adverse effects of rising temperature is moderated due to increase of CO₂ with the increase in photosynthesis when considered together. The leaf area index as well as evapotranspiration rate increase with increasing temperature and CO₂ for all varieties in all sowing dates. Whereas, the harvest index and maturity dates decrease in general. Therefore, increasing temperature at the present rate will be harmful for the productivity of cotton with the changing climate. Although this effect is abated with simultaneously rising CO₂ but yet the adversity due to global rise in temperature is partially mitigated.