Full Length Research Paper

Phenotypic and genotypic screening of rice genotypes at seedling stage for salt tolerance

Salil Kumar Bhowmik¹*, Soubir Titov², Mirza Mofazzal Islam³, Ayesha Siddika¹, Sharmin Sultana¹ and M. D. Shahidul Haque¹

¹Department of Biotechnology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh, India.

²Department of Applied Biology, Faculty of Agriculture and Forestry, University of Helsinki, FI-00014, Helsinki, Finland.

³Bangladesh Institute of Nuclear Agriculture, P. O. Box 4, Mymensingh 2200,   Bangladesh, India.

*Corresponding author. E-mail: salil_kist@yahoo.com.

Accepted 25 September, 2008

   Abstract

Selection for salinity tolerance genotypes of rice based on phenotypic performance alone is less reliable and will delay progress in breeding. Recent advent of molecular markers, microsatellites or simple sequence repeats (SSRs) are used to find out salt tolerant rice genotypes. Three selected SSR markers; RM7075, RM336 and RM253 were used to evaluate rice genotypes for salt tolerance. Phenotypic and genotypic evaluation for salinity tolerance was done at the seedling stage. Phenotyping of 11 genotypes was done in hydroponic system using salinized (EC 12 dS/m) nutrient solution. IRRI standard protocol was followed to evaluate salinity tolerance. Large variation in salinity tolerance among the rice germplasms was detected. Plant height and total dry matter of tolerant lines were reduced by 19.0 and 40.6%, respectively under salt stress (EC 12 dS/m), whereas those of susceptible lines were reduced by 46.0 and 73.5%, respectively. The markers showed polymorphism and were able to discriminate salt tolerant genotypes from susceptible. The genotypes having similar banding pattern with Pokkali were considered as salt tolerant. The SSR markers (RM7075, RM336 and RM253) identified 8, 9 and 7 salt tolerant genotypes, respectively. Through phenotypic and genotypic study, three genotypes viz., Pokkali, TNDB-100 and THDB were identified as salt tolerant rice cultivar. These SSR markers might have sequence homology with salt tolerant rice genotypes and consequently the markers could able to identify salt tolerant rice genotypes from susceptibles.

Key words: Rice, salinity tolerance, SSR markers, seedling stage.