TEMPERATURE CRITICAL THRESHOLD FOR YIELD IN CHILI PEPPER (CAPSICUM ANNUUM L.)

Chili (Capsicum annuum L.) is a horticultural plant susceptible to high-temperature stress. This research studied how agronomic and physiological characteristics of chili decline due to high temperature and determined the threshold value of temperature decreasing 50% of its yield. The experiment layout followed a randomized design, consisting of five temperature stress levels (in the growth chamber), namely, 31 degrees C (daily temperature as a control), 33 degrees C, 35 degrees C, 37 degrees C, and 39 degrees C, with an exposure duration of 10 h. The temperature stress started when the plant reached the flowering phase. The plant parameters observed included agronomic and physiological characteristics. The study results showed that high-temperature decreased production significantly with the decline in all agronomic and physiological traits. The threshold temperature at 32.86 degrees C has reduced the production of chili plants by 50% compared with the control. The study found that an increase in temperature of 2 degrees C for 10 h in the flowering phase reduces chili production by 68.78%, and temperature stress at a maximum of 39 degrees C for 10 h during flowering reduces chili production up to 87.52%. Hence, based on the study results, future research on chili should focus on developing varieties that are adaptive to high temperatures.