Stability analysis of yield and capsaicinoids content in chili (Capsicum spp.) grown across six environments

There is a need for identifying chili cultivars with stable amounts of capsaicinoids so that the amount of pungency in the final product can be controlled. Therefore, six cultivars were evaluated for yield and capsaicinoid contents across six environments, four in Thailand and two in Bhutan, ranging from 200 to 1,630 m above mean sea level. Combined analyses showed significant differences among cultivars, environments, and for cultivar by environment interactions for fruit yields, individual capsaicinoid and total capsaicinoid contents. A large proportion (46.1 %) of variation on yield was attributed to environments; however, for total capsaicinoid contents, genotype effect accounted for 74.2 % of variation. Variation due to environment was 5.8 %, while for cultivar by environment interaction was 15.8 %. Cultivar Dallay khorsaney had high capsaicin, dihydrocapsaicin and total capsaicinoids but was very sensitive to environmental changes, and therefore good for specific adaptation. Cultivar KKU-P-11003 with total capsaicinoid contents of 78,721 Scoville heat unit was stable for dry fruit yield, capsaicin, dihydrocapsaicin, and total capsaicinoids with regression coefficients b = 1.06, 1.06, 0.78, and 0.96 respectively. Therefore, KKU-P-11003 was considered suitable for diverse environments. In addition, this result indicates that it is possible to select stable cultivar for capsaicinoid contents.