Identification, Characterization and Validation of Salt Tolerance Determinants in Rice (Oryza sativa L) Landrace Horkuch and Its Segregating Population

Bangladesh is affected by salinity in more than 1 million hectares of coastal lands. The affected area forms a ninth of the total cultivable area. As a result, there is an urgent need for developing salt tolerant high yielding rice  varieties. This in turn demands an appropriate donor for salt tolerance traits. The rice landrace Horkuch (Oryza sativa L) from the Bangladesh coast was previously identified as a potential but novel donor, which maintains efficient photosynthesis and detoxification mechanism under salt stress. The current study aims to identify and  characterize salt tolerance associated QTL as well as differentially regulated genes under salt stress in Horkuch.  Two reciprocally crossed mapping populations were generated between Horkuch and high yielding but salt  sensitive variety IR29 where the F_2:3 design is being implemented in the mapping. Phenotypic characters affected  by salinity at   the    seedling   stage were observed in the F₃ population and the parameters were found highly  correlated with the level of salt injury. Phenotyping at the reproductive stage has also been noted. Genotyping of  the F₂segregating population is being carried out by double digested RAD sequencing which should allow clear  identification of DNA sequences segregating with tolerant or sensitive progenies. At the same time Expression QTL  mapping by RNAseq analysis of the selected tolerant or sensitive progenies are being carried out which will also  identify differentially expressed genes among the sensitive and tolerant progenies. In future, the identified QTLs  will be validated for their role on the tolerant phenotype and pyramided into breeding lines for achieving durable  salt tolerant but high yielding rice varieties.

(first 3 authors contributed equally)