Identification of major QTLs associated with stable resistance of tomato cultivar 'Hawaii 7996' to Ralstonia solanacearum

Issue Date

11-2012

Abstract

Bacterial wilt caused by Ralstonia solanacearum is one of the most devastating diseases of tomato. Tomato cultivar 'Hawaii 7996' has been shown to have stable resistance against different strains under different environments. This study aimed to locate quantitative trail loci (QTLs) associated with stable resistance using 188 recombinant inbred lines (RILs) derived from 'Hawaii 7996' and 'West Virginia 700.' A new linkage map with good genome coverage was developed, mainly using simple sequence repeat markers developed from anchored bacterial artificial chromosome or scaffold sequences of tomato. The population was evaluated against phylotype I and phylotype II strains at seedling stage or in the field in Indonesia, Philippines, Taiwan, Thailand, and Reunion. Two major QTLs were identified to be associated with stable resistance. Bwr-12, located in a 2.8-cM interval of chromosome 12, controlled 17.9-56.1 % of total resistance variation. The main function of Bwr-12 was related to suppression of internal multiplication of the pathogen in the stem. This QTL was not associated with resistance against race 3-phylotype II strain. Bwr-6 on chromosome 6 explained 11.5-22.2 % of the phenotypic variation. Its location differed with phenotype datasets and was distributed along a 15.5-cM region. The RILs with the resistance allele from both Bwr-12 and Bwr-6 had the lowest disease incidence, which was significantly lower than the groups with only Bwr-12 or Bwr-6. Our studies confirmed the polygenic nature of resistance to bacterial wilt in tomato, and that stable resistance in 'Hawaii 7996' is mainly associated with Bwr-6 and Bwr-12. © 2012 Springer Science+Business Media Dordrecht.

Source or Periodical Title

Euphytica

ISSN

0014-2336

Volume

190

Issue

2

Page

241-252

Document Type

Article

Physical Description

tables

Language

English

Subject

Bacterial wilt, Linkage map, Simple sequence repeat, Solanum lycopersicum

Identifier

doi:10.1007/s10681-012-0830-x.

Digital Copy

yes

Link to Full Text

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