1992 AJCS 13(12):1992-2002 (2019) ISSN:1835-2707 doi: 10.21475/ajcs.19.13.12.p1975 Mitigating chilling stress of pepper plant (Capsicum annuum L.) using Dimethyl Ether combustion gas in controlled greenhouse Jayanta Kumar Basak 1,2 , Waqas Qasim 1 , Frank Gyan Okyere 1 , Fawad Khan 1 , Yong Jin Lee 1 , Jihoon Park 1 , Hyeon Tae Kim 1* 1 Department of Bio-systems Engineering, Gyeongsang National University (Institute of Agriculture & Life Science), Jinju 52828, Korea 2 Department of Environmental Science and Disaster Management, Noakhali Science and Technology University, Noakhali-3814, Bangladesh *Corresponding author: bioani@gnu.ac.kr Abstract In this study, the possibility of enhancing chilling stress tolerance of pepper plant (Capsicum annuum Linnaeus) during early growth stages was investigated using DME combustion gas in controlled greenhouse. The experiment was conducted to determine the performance of DME combustion gas when used as a fuel for DME burner for raising temperature and CO 2 concentration in greenhouse and also to examine its effects on morphology parameters of hot pepper in winter season. To analyze the relationship between the application of DME and morphology parameters of pepper plant, three treatments (DME-1, DME-2 and DME-3) for three controlled greenhouses were assayed. DME-1 and DME-2 treatments consisted of average DME flow quantity in duct were 17.4 m 3 /min and 10.2 m 3 /min, respectively to greenhouse-1 and greenhouse-2 and no DME gas was supplied to greenhouse-3 which was left as control (DME- 3). Morphology parameters such as plant height, leaf area and leaf area index (LAI), net assimilation rate (NAR), relative growth rate (RGR), fresh weight and dry weight were measured for eight weeks for each treatment and analyzed using completely randomized designs through analysis of variance with a significance level of P < 0.05. Although DME-1, DME-2 and DME-3 received same crop management practices and controlled environmental factors, the highest changes (p < 0.05) of plant height, leaf area, LAI and fresh weight were found from the DME-1 treatment, followed by DME-2. A comparison of relative growth rates among the treatments indicated more rapid relative growth rate of morphology parameters at vegetative phase of plant implying better yield. Therefore endorsed quantify of DME combustion gas for a specified crop can be applied to greenhouse to improve the plant growth and enhance yield with mitigating chilling stress in winter season. Keywords: DME, Greenhouse, Pepper, Morphology parameters, Vegetative phase. Abbreviations: DME_ Dimethyl Ether; LAI_ Leaf area index, NAR_ Net assimilation rate; RGR_ Relative growth rate. Introduction The optimum temperature for growth of pepper plant is between 21 0 C and 27 0 C, with growth reduction occurring when temperature is below 12 0 C and above 30 0 C. The plants give the best yield and better seed set at the temperature range between 21 0 C to 27 0 C during the day time and 15 0 C to 20 0 C at night (Kahsay, 2017; Aleemullah et al., 2000; Lemma, 1998). Lack of optimum temperature during the critical growth stage of pepper plant may hamper yield (Reddy and Kakani, 2007). Exposure of plants to chilling temperatures during winter season may stunt plant growth, induce wilting, cause necrotic lesions on leaves, and increase susceptibility to diseases and pathogens. This study attempts to measure performance of DME gas to mitigate chilling stress of pepper plant by increasing temperature and CO 2 concentration in controlled greenhouses. In Korea, pepper is usually cultivated in greenhouses during winter season due to the extreme cold temperature and to control other growth variables. Low temperature during winter is reported to be one of the most challenging factors that affect yield significantly (Hong et al., 2018; Schwartz et al., 2006; Wolfe et al., 2005; Xiao et al., 2008; Rosenzweig, 2002). For proper growth of pepper plant, it is essential to maintain warm and high humid climatic conditions, however at maturity stage, it requires dry weather.