Screening of different bitter gourd breeding lines for bacterial wilt disease (Ralstonia solanacearum) and develop disease control methods.

Abstract

Bitter gourd (Momordica charantia) is one of the famous highly medicinal value vegetable crops in the Sri Lanka. The bacterial wilt disease caused by Ralstonia solanacearum is known with negative effect in crop production. The studies related to screening of resistant varieties for this disease is less known. Therefore, this study was aimed to assess the resistance levels of various bitter gourd breeding lines against bacterial wilt disease and to develop an effective eco-friendly disease control method. The experimental design employed in this study follows Complete Randomize Design. Pathogen was isolated from diseased plant and pathogenicity test was done. Healthy bitter gourd plants were inoculated with bacterial suspension, and disease incidence was assessed within 14 days after inoculation. Data analysis was done using the SAS 9.4 version. Data were analyzed by Analysis of Variance and means were compared by Duncan's Multiple Range Test. The disease incident scale was considered according to the protocol of the Asian Vegetable Research and Development Centre. Different bitter gourd lines were screened for their susceptibility or resistance to bacterial wilt, resulting in the categorization of Neerogi (7%) and Thinnaveli white (9%) as resistant, MC43 as moderately resistant (18%), MG (25%) as moderately susceptible, Matale green (70%), Kalu karavila (65%), and Krishna (50%) as susceptible. In addition to this, five soil amendments were used for the effective control measures (paddy husk biochar (1 and 2 kg/m2), bordex mixture, champ fungicide, and lime powder). This investigation revealed that amending the soil with lime powder at a rate of 500 g/m2 (T-5) proved to be the most suitable and effective method for controlling bacterial wilt disease and improving flowering and fruit formation. This method demonstrated not only high efficacy but also costeffectiveness and environmental friendliness compared to other treatments. Additionally, Bordex mixture and Champ fungicide exhibited moderate activity in disease control. Findings of this research provide valuable insights into the management of bacterial wilt disease in bitter gourd cultivation, emphasizing the importance of adopting eco-friendly and cost-effective methods for sustainable agriculture.