Evaluating the growth and water use efficiency of chili pepper ‘Tanjung’, ‘Unpad’, and ‘Osaka’ using SFM1 sap flow in agro-environment

Water use efficiency in horticultural crops is necessary for sustainable agriculture, especially under changing micro climate conditions. This study assesses the water use efficiency (WUE), growth, and physiological performance of three chili cultivars (Tanjung, Unpad, and Osaka-3) under various conditions of agro-environment. The experiment was carried out from December 2023 to May 2024 at Universitas Padjadjaran in Indonesia, using a factorial randomized complete block design with 432 plants spread among four conditions of agro-environment: greenhouse, rain shelter, screen house, and open field. Plants were given nutrient solutions in varied quantities based on evapotranspiration (ETc) in four conditions of agro-environment. a Sap Flow Meter (SFM1) with the Heat Pulse Velocity technique measure volume of nutrient solution for watering the plants which was predicted using a soil water balance model. The results revealed interaction and significant effect of cultivar and four conditions of agro-environment that influenced water intake, sap flow, and growth. Osaka had the highest water sap velocity, indicating intense transpiration, particularly in the screen house and open field. Tanjung performed best in the screen house, with the maximum WUE (2.0 g/L) and absolute growth rate (> 0.60 cm/day), despite the low water usage. Correlations between sap velocity and water consumption for absolute growth rate (AGR) was 0.68* and WUE was 0.59. These findings emphasize the significance of controlled conditions of agro-environment designs to maximize water use efficiency and maintain chili productivity.