Effect of nutrient solution and temperature on capsaicin content and yield contributing characteristics in six sweet pepper (Capsicum annuum L.) cultivars

Capsaicin is a unique pungent ingredient in Capsicum spp. and mechanism responsible for the increase in capsaicin content in non-pungent Capsicum spp. is an important task. Capsaicin biosynthesis is regulated by developmental and environmental factors. In this study, capsaicin content in green and ripe fruits in six cultivars of sweet pepper and yield contributing characters by applying temperature and nutrient solution formulations were investigated. Six cultivars of sweet pepper (e.g., V-1 Wonder bell, V-2 Furupi-red, V-3 Papri-E-red, V-4 Papri new-E-red, V-5 AVRDC PP 0436-6055, and V-6 AVRDC PP 0436-6006) were grown under two growing conditions of high temperature (T-1) and low temperature (T-2) applying three nutrient formulations (e.g., S-1 Hoagland and Amon No. 2, S-2 double strength of Si, and S-3 customized nutrient formulation) using solid soilless culture technique. The capsaicin content differed among six cultivars, two different temperature conditions and three nutrient solution formulations. The highest capsaicin content of fruits was found from V-6 cultivar and S-3 treatment grown under high temperature treatment (T-1) over low temperature (T-2). The capsaicin content was higher in ripe fruits than in green fruits of sweet pepper at both of the temperature treatments applying S-3 nutrient formulation. The capsaicin biosynthesis involved the activity of capsaicin synthase in the placental tissue, and capsaicin synthesis might be increased in high temperature, nutrient solution formulation and advancement of fruit maturity. Therefore, high temperature and nutrient solution formulation had important effects on capsaicin contents at both of the fruit maturity stages in sweet pepper cultivars. The improving tendency in yield and yield contributing characters was found in high temperature treatment and customized nutrient formulation in V-6 and V-4 cultivars. In our study nutrient formulation and high temperature had positive effects on yield and yield contributing characters in sweet pepper.