Impact of Environments on the Accumulation of Capsaicinoids in Capsicum spp.

The use of a chili fruit is distinguished by its capsaicinoid content, which shows many beneficial effects in food and pharmaceutical applications. However, chilies exhibit wide variations in the accumulation of capsaicinoids depending on their genotype and environmental interaction. Therefore, we conducted experiments to evaluate the capsaicinoid responses of 14 cultivars of chili across four different elevations. Experiments were conducted during the rainy season from June to Oct. 2009 at elevations of 200 m asl (Khon Kaen) and 680 m asl (Chiang Mai) in Thailand and from Apr. to Sept. 2010 at elevations of 1400 m asl (Lobesa) and 1630 m asl (Kabesa) in Bhutan. A high-performance liquid chromatography technique was used to determine capsaicin and dihydrocapsaicin. Significant differences were observed among the cultivars, the locations, and the cultivar-by-location interactions. Large variations of cultivar effects indicate that it is possible to select cultivars for capsaicinoid concentration that are adapted over a wide range of environments. Average capsaicin, dihydrocapsaicin, and total capsaicinoids were greater at higher elevations in a particular year. There was significant correlation between capsaicin and total capsaicinoid contents with elevations, but capsaicinoid yield showed negative correlation. Small-fruited cultivars with high pungency showed consistent capsaicinoid production over different environments. Dallay khorsaney, KKU-P-22006, KKU-P-31141, and KKU-P-21041 cultivars showed high stability for pungency, producing high capsaicinoids at all four locations.