Evaluation of Resistance to Race 3, Biovar 2 of Ralstonia solanacearum in Tomato Germplasm

Abstract

Sources of resistance to tropical race 1 strains of Ralstonia solanacearum, the causative agent of bacterial wilt, have been identified in the tomato germplasm. Till now, no experimental data are available on Lycopersicon spp. (now Solanum spp.) sources for resistance to temperate race 3, biovar 2 strains. Eighty-two accessions belonging to different Lycopersicon spp. were evaluated for resistance to a race 3 strain endemic to Re´union Island. Evaluation was conducted in growth chambers, and included the Lycopersicon esculentum cv. Roma as susceptible control. No immunity or complete resistance was observed in any accession tested under our experimental conditions. Therefore, race 3 strain was demonstrated to be highly pathogenic on all the Lycopersicon accessions tested. Partial resistance was significantly detected in only one accession belonging to the species Lycopersicon peruvianum, and one L. esculentum var. cerasiforme tomato line. Five other genotypes from the species L. esculentum, Lycopersicon hirsutum and L. peruvianum were noteworthy. The Hawaii 7996 line represented the best source of partial resistance to race 3 with 52% of wilting. It can therefore be used as a starting point for introducing resistance to bacterial wilt caused by R. solanacearum race 3 in tomato and studying its genetic control.

Chemical Pesticides and Plant Essential Oils for Disease Control of Tomato Bacterial Wilt

“…For disease control of bacterial wilt, planting resistance cultivars were screened and suggested. A few tomato cultivars had R. solanacearum resistance in recent studies (Carmeille et al, 2006;Han et al, 2009;Nakaho et al, 2004). However, changing resistant cultivars can sometimes lead to undesirable tomato traits.…”

Grafting to Manage Soilborne Diseases in Heirloom Tomato Production

“…In Hawaii 7996, the movement of R. solanacearum is limited from the protoxylem into other xylem tissue, and this breeding line has been identified for future breeding programs in Japan (Nakaho et al, 2004). Hawaii 7996 has also been identified as a viable source of resistance for managing bacterial wilt caused by R. solanacearum (race 3, biovar 2) (Carmeille et al, 2006 problematic in many southeastern U.S. crops, including tomato, potato, tobacco, and eggplant. Control of BW in tomato is very difficult.…”

Resistance to Taiwanese race 1 strains of Ralstonia solanacearum in wild tomato germplasm

“…In previous studies, Hawaii 7996 was found to be highly resistant when evaluated in fields located in 11 countries and territories (Wang et al 1997). However, it displayed partial resistance against a race 3/biovar 2/phylotype II strain isolated from potato in Reunion (Carmeille et al 2006b) and three strains of a new pathogenic variant of R. solanacearum named phylotype II/4NPB, described recently (Wicker et al 2007). Therefore, it is necessary to evaluate the new S. pennellii resistance sources reported here against strains with a wider diversity to determine their potential use.…”

“…More recently, partial resistance to a strain of race 3 biovar2 phylotype II was detected in one accession belonging to S. peruvianum, and one S. lycopersicon var. cerasiforme accession among the 82 accessions screened (Carmeille et al 2006b). Summarizing the results from previous studies, it may be worthwhile to more intensively evaluate the accessions of S. lycopersicon var.…”