Molecular mapping of quantitative trait loci associated with seedling tolerance to salt stress in rice (Oryza sativa L.)

Quantitative trait loci (QTL) controlling various rice seedling traits conferring salt tolerance were mapped on the molecular map of rice, generated by using a doubled haploid population derived from the cross between IR64 and Azucena, Seven QTL were identified [threshold LOD (log of odds ratio) greater than or equal to 2.00] for seedling traits under salt stress, i.e. two for seed germination (%), one for seedling root length (cm), three for seedling dry matter (mg) and one for seedling vigour. Among the seven QTL four were located on chromosome 6. A QTL for root length on chromosome 6 was flanked by restriction fragment length polymorphism (RFLP) markers RG162-RG653, exhibited a very high phenotypic variance of 18.9% and a peak LOD score of 2.852. Homozygous genotypes containing quantitative genes tolerant to salt stress were identified, The markers tightly linked to salt tolerance can be used in marker-assisted selection after testing their stability and reliability.