Growth responses of hot chilli (Capsicum Chinense jacq.) to elevated carbon dioxide and temperature

Abstract

The current study was carried out to evaluate the response of hot chilli (Capsicum chinense Jacq.) to elevated CO2 and temperature for two consecutive years by using CTGT (Carbon dioxide Temperature Gradient Tunnel) technology at Assam Agricultural University, Jorhat. Hot chilli plants were grown at different conditions viz. ambient (open condition); CTGT I (380 ppm CO2 and ambient temperature); CTGT II (550 ppm CO2 + 2oC temperature elevation from CTGT I) and CTGT III (750 ppm CO2 + 4oC elevation from CTGT I). Results of the study revealed that plants grown at CTGT II and CTGT III recorded a significant increase in root: shoot ratio, leaf area index (LAI), leaf area duration (LAD) in both the year of experimentation. An increase in specific leaf weight (SLW) and a decrease in specific leaf area (SLA) was observed due to the elevation of CO2 and temperature at CTGT II. A highly significant positive correlation (r = 0.997) was obtained between SLW and LAI. Further, LAD showed a significant positive correlation (r = 0.968) to fruit yield per plant. Regression analysis revealed 79.1 % contribution of LAD to the fruit yield. Amongst the two cultivars (cv. Manipur and cv. Assam), cv. Manipur performed better in terms of morphological and growth parameters under elevated carbon dioxide and temperature conditions. This indicates the differential responses of hot chilli genotypes under future climate change conditions. Thus, the current study documented that elevated CO2 @ 550 ppm and 2OC temperature may favor the production of Bhut Jolokia due to enhanced assimilation of CO2.