QTL mapping for salinity tolerance in rice using Kalarata-Azucena population
2012
de Ocampo, M.P. | The, H.V., Institute of Life Sciences, Scuola Superiore Sant' Anna, 34 Mariscoglio Street 56124, Pisa (Italy). Plantlab | Egdane, J.A. | Zantua, R.E. | Thomson, M.J. | Ismail, A., International Rice Research Inst., DAPO 7777, Metro Manila (Philippines)
Salt stress is a major constraint across large rice-producing areas because of the high sensitivity of modern rice varieties. To identify QTLs associated with salinity tolerance in rice, the authors developed an F2 population from a cross between salt-tolerant parent, Kalarata, and the salt-sensitive parent, Azucena. A population of 177 F2 plants was used for DNA extraction, and F2:3 families from this population were screened in the Phytotron in saline nutrient solution at seedling stage. After 2 weeks at an EC of 12 dS/m, families were scored for salinity tolerance using IRRI's standard evaluation system (SES). Seedling growth, biomass, Na+ and K+ and chlorophyll concentrations in the leaf tissue were determined. A genetic linkage map was constructed with 151 SSRs and InDel markers, covering 1463 cM with an average distance of 9.69 cM between Loci. A total of 16 QTLs were identified using composite interval mapping with 23 traits studied. The short arm of chromosome 1 had the highest density of detected QTLs responsible for salinity tolerance and seedling vigor, which coincide with the Saltol locus, emphasizing the importance of this locus for candidate gene discovery and use in rice breeding. Few novel QTLs were identified on other chromosomes, and these constitute future targets for molecular breeding.
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