Combining ability of tomato inbred lines to bacterial wilt resistance

Abstract

Tomato is one of the most important crops worldwide. Bacterial wilt (BW), caused by Ralstonia spp., is a major disease for tomato production around the world, especially in tropical and subtropical regions. Currently in Brazil, only commercial hybrids are available as resistant rootstocks for use in infested areas, and we lack information regarding resistance to aggressive strains. Thus, the aims of this work were to estimate combining abilities of five tomato inbred lines and hybrids and to identify resistant genotypes for using as rootstocks resistant to Ralstonia solanacearum biovar 2, phylotype II, one of the most aggressive strains in Brazil. Combining abilities for BW resistance were assessed through full diallel crossings among five tomato inbred lines without reciprocals. The experiment was carried out in a greenhouse, in a complete randomized blocks design, using 15 genotypes (hybrids and parents). Additive genetic effects showed to be the most important for controlling bacterial wilt. The inbred line Hawaii 7996 exhibited the highest general combining ability among the five parents assessed. The hybrid Hawaii 7996 × Rodade was the best crossing in terms of resistance and specific combining ability, which was greater than those of all other hybrids. Although Hawaii 7996 remains as a major source for BW resistance, further researches are needed to better understand the resistance dynamics, seeking to develop hybrids with transgressive segregations and more stable resistance against aggressive strains and thrive under environmental conditions highly favorable to bacterial wilt infection.

Incidence and Severity of Bacterial Wilt Disease on Three Eggplant (Solanum melongena L.) Varieties in Central Uganda.

“…Ralstonia solanacerum is a soil-borne pathogen that infects the xylem tissue of plants through natural openings or wounds (Vasse et al, 1995;Huet, 2014). It usually manifests as wilt that begins from the upper parts of the plant, eventually spreading to the entire plant, causing death under favourable environmental conditions such as warm temperatures (between 25°C and 37°C) and high soil moisture (Lopes, 2009). Under unfavourable conditions (such as temperatures below 15°C or higher than 37°C and drought conditions), plants grow slowly and may appear to be stunted.…”

Ralstonia solanacearum pandemic lineage strain UW551 overcomes inhibitory xylem chemistry to break tomato bacterial wilt resistance

“…Introgressing this resistance into commercial cultivars is difficult because undesirable agronomic traits like small fruit size are tightly linked to the resistance QTLs (Carmeille et al., 2006 ; Opina et al., 1990 ; Wang et al., 1998 ; Yuliar et al., 2015 ). Despite these difficulties, the Hawaii breeding lines are the source of nearly all tomato bacterial wilt resistance worldwide (Brand‐Daunay et al., 2010 ; Ho et al., 2013 ; Lopes et al., 2022 ; Scott et al., 2009 ; Wang et al., 2000 ).…”

Ralstonia solanacearumpandemic lineage strain UW551 overcomes inhibitory xylem chemistry to break tomato bacterial wilt resistance

“…Introgressing this resistance into commercial cultivars is difficult because undesirable agronomic traits like small fruit size are tightly linked to the resistance QTLs (Opina et al, 1990;Wang et al 1998;Carmeille et al 2006;Yuliar & Toyota, 2015). Despite these difficulties, the Hawaii breeding lines are the source of nearly all tomato bacterial wilt resistance worldwide (Lopes et al 2022;Brand-Daunay et al 2010;Ho et al 2013;Scott et al 2009;Wang et al 2000).…”