Summary: Bacterial wilt caused by race 1 strains of Ralstonia solanacearum is one of the most important and widely distributed plant diseases in the tropics and subtropics, particularly on tomato. Planting resistant material is the most suitable measure for the control of tomato bacterial wilt. To elucidate genetic control of resistance in Hawaii 7996, a stable resistance source, a population of 188 F9 recombinant inbred lines (RILs) derived from a cross between S. lycopersicum Hawaii 7996 (resistance parent) and S. pimpinellifolium West Virginia 700 (susceptible parent) was used for this study. First, the genetic map was improved, and a total of 362 markers including 74 AFLP, 260 DArT, 5 RFLP, 1 SNP, and 22 SSR markers was used for map construction. Total of ten major and two minor linkage groups spanning 2131.7 cM were identified. A framework map of 106 loci (32 AFLP, 59 DArT, 6 RFLP, 11 SSR) distributed over 15 linkage groups covering 1089.1 cM was used for quantitative trait loci (QTL) mapping with the composite interval mapping method. The phenotypic data used for the QTL analysis included 9 datasets: 3 for disease evaluations and 6 for morphological traits. Disease reactions of the RIL population were evaluated against two phylotype 1, race 1 strains (Pss4 and Pss181) at seedling stage. A total of 13 QTLs were identified. Out of these 13 QTLs detected, 7 QTLs were identified for bacterial wilt resistance, one for sympodial index, two for citric acid, two for soluble solid content and one for fruit color (a/b). They explained between 5.0% and 20.1% of the phenotypic variation, depending on the traits. Resistance in Hawaii 7996 is related to the suppression of the pathogen colonization in the stem, as similar QTLs were found based on visual symptom data as well as colonization data caused by Pss4. Possible linkages between critic acid and bacterial wilt resistance was observed. QTLs located on chromosome 6 showed significant linkages with disease reactions against several pathogen strains should be targeted for fine mapping and developing closely linked markers for marker-assisted selection and gene cloning.
Type: Non-ISI/SCOPUS listed journals with ISSB/ISBN
Author: Trương Thị Hồng Hải, Jaw-Fen Wang, E.B. Graham, E. Esch
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Journal:The First Asian Horticultural Congress (AHC 2008)
Issue, Number, Pages85
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Year of publication: 2008
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