RESPONSES OF MICROPROPAGATED KEPOK BANANA TREATED BY SILICA AND CHITOSAN AS ELICITORS PROCEEDED BY FUSARIUM OXYSPORUM F. SP. CUBENSE TROPICAL RACE 4 IN VITRO INOCULATION

• Main Author: Jessica Padmadewi Kemunin, Putu
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47031
• Institution: Institut Teknologi Bandung

Fusarium wilt causes devastating decline of banana production in Indonesia. The disease is caused by the fungus Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4). Several means are done to increase plant resistance to Foc TR4, one of which is elicitation. Silica and chitosan are among potential elicitors which are thought to be able to increase banana resistance to fusarium wilt. This study aims to analyse physiological responses of kepok banana plantlets treated by sodium silicate 15 ppm, 30 ppm, and 60 ppm and chitosan 20 ppm, 40 ppm, and 80 ppm before in vitro inoculation with Foc TR4. The method used consists of measuring disease severity index, measuring growth parameters such as pseudostem length, leaf total chlorophyll content, measuring enzymatic activity of polyphenol oxidase (PPO), peroxidase (PO), and phenylalanine ammonia lyase (PAL), and measuring tissue and medium phenolic compounds. The observations showed that these elicitors were able to reduce the disease severity index of kepok banana plantlets inoculated with Foc TR4, 14 days after inoculation. The Rhizome Discoloration Indices (RDI) of rhizomes treated by silicate were 2.33; 3; and 1.67 which are categorized as tolerant. RDI of rhizomes treated by chitosan were 1.33; 1.33; (tolerant) and 1 (resistant). These are lower than the positive control, which is considered vulnerable (RDI: 5). Leaf Severity Indices (LSI) didn’t show any difference among treatments. LSI of leaves treated by silicate are 2; 1.33; 1.5 (tolerant) while chitosan are 1, 1, (resistant) and 1.33 (tolerant). Treatment with sodium silicate causes better pseudostem growth compared to chitosan treatments and control. Chitosan increases chlorophyll content better than silicate treatments and control. Plantlets that were treated by chitosan had higher PPO, PO, and PAL enzyme activities compared to control and sodium silicate treatments. The concentration of phenol compounds in the treated showed an increase. The increase in the concentration of phenol compounds in the medium only occurred in the control and chitosan treatments. The results showed that at given concentrations, sodium silicate was able to stimulate plantlet growth and chitosan was able to increase of defence-related compounds production so that it could be concluded that the plantlets treated by both types of elicitors had better resistance to Foc TR4.