Construction of a single nucleotide polymorphism marker based QTL map
And validation of resistance loci to bacterial wilt caused by Ralstonia solanacearum species complex in tomato
Abstract
Bacterial wilt (BW), caused by Ralstonia solanacearum species complex is one of the major biotic factors limiting tomato production in the humid tropics. Pyramiding of resistance genes through marker-assisted selection is an efficient way to develop durable BW resistant cultivars. Tomato line ‘Hawaii 7996’ (H7996) is a stable and robust resistance source against various strains of the species complex. Major BW resistance quantitative trait loci (QTLs) Bwr-12 and Bwr-6, and several minor or strain specific QTLs have been coarse-mapped in this line, but none has been fine-mapped and validated. The objective of the current study was to construct a high density genetic map using single-nucleotide polymorphism (SNP) markers derived from genotyping-by-sequencing, fine-map Bwr-12 and Bwr-6 and determine the effects of these QTLs using a near isogenic line (NIL) population. A total of seven QTLs associated with BW resistance to race 1-phylotype I (R. pseudosolanacearum) or/and race 3-phylotype II (R. solanacearum) strains were located on chromosomes 6 (Bwr-6.1, 6.2, 6.3 and 6.4) and 12 (Bwr-12.1, Bwr-12.2 and Bwr-12.3) with logarithm of odds (LOD) scores of 6.2–15.6 and 6.2–31.1, explaining 14.2–33.4% and 15.9–53.9% of the total phenotypic variation contributed from H7996, respectively. In addition, the specific effect of Bwr-12 for resistance to Pss4 (LOD score of 5.8-16.1, P < 0.01) was confirmed.
This article is the result of funding from the World Vegetable Center. The World Vegetable Center is partly funded by the UK Foreign, Commonwealth and Development Office (FCDO)
Citation
Shin, I.S., Hsu, J., Huang, S. et al. Construction of a single nucleotide polymorphism marker based QTL map and validation of resistance loci to bacterial wilt caused by Ralstonia solanacearum species complex in tomato. Euphytica 216, 54 (2020). https://doi.org/10.1007/s10681-020-2576-1