Assessment of salt tolerance and variability within some rice germplasm using microsatelittes

Soil salinity is a major abiotic stress that affects rice production. It can reduce yield drastically and result in total crop failure. The objectives of this study are to determine the genetic diversity within thirty-six rice accessions and to identify genotypes that are tolerant to salinity. Thirty-six rice accessions including three check varieties were sown in experimental pots and their leaves harvested for DNA extraction. Screening was done with 31 simple sequence repeats (SSRs) primers, of which 14 were markers for salt tolerance, 2 primers did not produce any results. 28 out of the 31 primers were polymorphic. The polymerase chain reaction (PCR) products were run and visualized on a 3% agarose gel matrix stained with ethidium bromide. Amplified bands were scored and analyzed with PowerMarker v3.25 and DARwin v5 software. The genetic diversity among the accessions assembled was high (He=0.6, I=0.516, PIC=0.471). Saltol primers RM10711 and RM10793 were the only primers able to completely discriminate tolerant genotypes from susceptible ones, hence they can be used in selections involving the genotypes. Accessions SR1, IR72, Sebota 337-1, Perfume (Short) type, Anyofula, Local Red, GR18Red, GH1580, GH1528, GH1575, NericaL23, NericaL24 and NericaL27 performed well under salinity stress in this study and were identified to be superior among the accessions used. These accessions should be incorporated into major breeding programs to improve the salt tolerance of existing commercial lines or for the production of new commercial lines. Key words: Rice, abiotic stress, agarose gel, genetic diversity, polymerase chain reaction (PCR), simple sequence repeats (SSRs) markers, salinity.