Identification of novel source and inheritance of resistance to bacterial wilt (Ralstonia solanacearum) in tomato (Solanum lycopersicum L.) for sustainable disease management

Abstract

Bacterial wilt caused by Ralstonia solanacearum is a destructive disease severely restricting tomato (Solanum lycopersicum L.) productivity in tropical and subtropical regions. The purpose of this study was to identify novel sources of resistance and explicate the inheritance pattern of bacterial wilt resistance in tomato.  A total of 59 genotypes, including open-pollinated lines, hybrids and breeding accessions, were subjected to screening experiments during two consecutive seasons (2022–2023 and 2023–2024) under controlled net house conditions at Centurion University of Technology and Management and natural epiphytotic field conditions at Indian Institute of Horticultural Research - Central Horticultural Experiment Station , Bhubaneswar, India. Disease severity was evaluated using percent disease index (PDI) and area under disease progress curve (AUDPC). The open-pollinated cultivar ‘Utkal Kumari (BT-10)’ exhibited consistent high resistance, with significantly lower AUDPC values (<150 vs >1800 in susceptible checks) and high survival rates (90 %) across environments. Among others, tomato cultivars Arka Samrat, Arka Abhed and JK Desi, demonstrated significant resistance while genotypes such as Pusa Ruby and EW815 were consistently highly susceptible. A segregating F₂ population derived from a cross between resistant ‘BT-10’ and susceptible ‘Pusa Ruby’ exhibited continuous variation in disease response. Chi-square analysis revealed significant deviation from a 3:1 Mendelian segregation ratio (χ² = 72.30, P < 0.01), indicating a quantitative mode of inheritance. These findings highlight the potential of Utkal Kumari and allied resistant lines as donors for resistance breeding and emphasize the need to integrate robust phenotypic screening with molecular approaches for durable and strategic bacterial wilt management in tomato.