Eco-friendly management modules for bacterial wilt (Ralstonia solanacearum) of tomato for protected cultivation in a tropical island ecosystem

Genetic approaches for mitigating losses caused by bacterial wilt of tomato in tropical islands

“…None of the genotypes showed stable resistance to bacterial wilt in subsequent years which could be due to variation in pathogen biovars and concentration in soil (Ramesh and Ansari 1989;Chellemi et al 1994;Hanson et al 1996;Jyothi et al 2012). Reactions of some genotypes against R. solanacearum agreed with reports of Agrawal et al (2000) and Singh et al (2014). Disease reaction of previously identified resistant genotypes needs to be confirmed as the host-pathogen interaction evolves with time and R. solanacearum might have also evolved to overcome the level of resistance in previously identified resistant genotypes (Jyothi et al 2012).…”

“…Hassan and Abo-Elyousr (2013) tried to investigate plant defence responses against R. solanacearum using DL-3-aminobutyric acid (BABA) but the link between hormonal shift in plants during transformation , 2012-13, 2012-14) from vegetative to reproductive stage and bacterial wilt incidence is still not clear. The incidence was low in pot culture primarily due to absence of predisposing factors such as nematode infection (Jayakumar et al 2006;Singh et al 2014) or chance of root damage by cultural practices which are common in field conditions. Variation in reports might be due to differences in crop age, variety, climatic temperature and humidity, soil type, previous crop, and management practices affecting bacterial populations and host tolerance levels (Michel et al 1996;Singh 2002;Jyothi et al 2012;Singh et al 2014).…”

“…The incidence was low in pot culture primarily due to absence of predisposing factors such as nematode infection (Jayakumar et al 2006;Singh et al 2014) or chance of root damage by cultural practices which are common in field conditions. Variation in reports might be due to differences in crop age, variety, climatic temperature and humidity, soil type, previous crop, and management practices affecting bacterial populations and host tolerance levels (Michel et al 1996;Singh 2002;Jyothi et al 2012;Singh et al 2014). Bacterial wilt incidence in ten genotypes of tomato had more negative correlation (r=−0.42; p<0.05) with yield during dry season than rainy season (r=−0.15; p<0.05) (CARI 1985) which could be due to prevalence of all three favourable factors i.e., congenial climate, susceptible host and sufficient time for pathogenicity (Singh 2002).…”

“…Thus, a wide range of wilt management options including crop rotation (Ramesh and Ansari 1989;Michel et al 1996); soil fumigation (Enfinger et al 1979); resistant germplasm (Sharma and Ansari 1987;Sharma et al 1997); grafting techniques and cocopith based growing media (Black et al 2003;Singh et al 2014); supplemental irrigation with sea water (van Elsas et al 2001); screening of antagonists (Jayakumar et al 2006;Lwin and Ranamukhaarachchi 2006;Amaresan et al 2012;Chakravarty and Kalita 2012;Feng et al 2013), and crop protection methods (Ramesh and Ansari 1989;Bhagat and Kumar 2010) are not commercially significant because R. solanacearum has a broad host range, widespread distribution, and great extent of genetic variability of R. solanacearum (Hayward 1991). Resistant varieties are suggested to be the only useful and rational solution to bacterial wilt in fragile ecosystem in tropical region ).…”

“…Resistant varieties are suggested to be the only useful and rational solution to bacterial wilt in fragile ecosystem in tropical region ). The varieties with stable and durable resistance to bacterial wilt in tomato could support other management strategies such as crop rotation, cocopith based growing media and grafting technique (Hanson et al 1996;Singh et al 2014). Transfer of bacterial wilt resistance gene(s) suffers from linkage drag wherein undesirable traits also get transferred with wilt resistance gene (Scott et al 1993;Jyothi et al 2012).…”