Increasing Chili (<i>Capsicum annuum</i>) Resistance to Yellow Leaf Curl Disease through Jasmonic Acid Application

Abstract Pepper Yellow Leave Curl Disease caused by Gemini viruses have become a major of diseases in horticultural plants worldwide, including chili. This research was conducted using lotanbar chili (local name in West Sumatra). Jasmonic acid is a signal hormone to induce the plant’s defense system when the plant is infected by virus. This study aims to determine the effect of application and optimum concentration of jasmonic acid on symptoms caused by gemini virus-infected chili peppers. The study used a randomized block design (RBD) and continued with Duncan’s Multiple Range Test (DMRT). The jasmonic acid application was varied based on concentration of 0, 50, 100, 150 μMol, and duration of application J1: 0, 20, 40 days after planting; J2: 20, 40, 60 days after planting. The 100 μMol treatment produced chilies weighing 898.12 g, while those not treated with jasmonic acid only had 251.56 g. The 100 μMol concentration resulted in a 257% increase in yield and a reduction in symptoms of gemini virus attacks. Jasmonic acid treatments also enhanced chlorophyll content, with the total chlorophyll increasing from 0.41 mg/L in untreated plants to 0.86 mg/L in treated plants, representing a significant improvement. However, applying more than 100 μMol suppressed plant growth.