Effects of Chitosan and Drought Stress on Morpho-Physiology and Resistance of Red Chili (Capsicum annuum L.) Infected by Colletotrichum scovillei Damm, P.F. Cannon & Crous

• Main Author: HUSNUL CHOTIMAH (NIM: 10614025), HANY
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/27720
• Institution: Institut Teknologi Bandung

<p align="justify">Chili productivity in Indonesia decreased from 8,65 to 8,47 tons/Ha during 2015-2016. The decrease was due to disease, such as anthracnose, which cause a rotten disease caused by Colletotrichum scovillei, one of the most virulent species. The use of alternative ingredients of chitosan as a substitute for fungicides is known to be able to improve morpho-physiological character and induce the response of chili plant resistance to pathogens. On the other hand, drought stress can increase capsaicin levels in chili, and it is reported that anthracnose-resistant chili cultivars have a higher capsaicin content compared to susceptible cultivars. Therefore, the aims of this study was to determine the effect of chitosan, drought stress, and combination of both on plant morpho-physiology and red chili resistance to C.scovillei attacks. In this study two chili cultivars (LADO and LABA) were used, which represented different resistance to anthracnose. The treatment started when plants enter the generative phase, by applying 1 mg/mL chitosan every week and a water deficit of 50% normal volume. Observations were made on various growth parameters (plant height, number of leaves, number of flowers, number of fruits), stomatal opening, and capsaicin levels from chili pericarp. Identification of fungi based on morphology and molecular was conducted to ensure that the species used was C.scovillei. Disease severity of red chili fruit was evaluated through scoring method (incidence and intensity of the disease) and PR1 gene expression analysis. The results showed that the application of chitosan and drought stress caused morpho-physiology, such as growth and chili yield, decrease. However, the application of 1 mg/mL chitosan and 50% drought stress was able to increase capsaicin levels in pericarp and red chili resistance to C.scovillei. The combination of the two treatments simultaneously caused greater increase in capsaicin levels and chili resistance than that in the control (increase in the resistance category of susceptible (LABA) and very vulnerable (LADO) to moderate). Increased of chili resistance was also confirmed by the result of analysis, that higher PR1 gene was expressed in LADO cultivars following chitosan treatment and drought stress compared to that in controls.<p align="justify">