Genetic diversity among four genotypes from Hibiscus rosasinensis in relation to drought stress

The effect of drought stress on growth and water relations of four Hibiscus genotypes was investigated. Drought stress significantly retarded vegetative growth as analyzed by plant height, stem diameter, leaf area, fresh and dry weight. The osmotic potential (ys) values decreased with increasing drought time, and the decrease was more pronounced in Fantasia followed by Jay´s orange. Osmotic adjustment (O.A.) increased with drought time, and was greater in Fantasia followed by Jay´s orange and lowest in Annie wood.  The genetic diversity among the four hibiscus genotypes was detected by Random Amplified Polymorphic DNA (RAPD) analysis. The data indicate that, thirty-one out of fifty four RAPD markers detected were polymorphic (57.4%). The RAPD specific markers for each genotype were determined. Ten out of the thirty one polymorphic RAPD markers generated were found to be genotype- specific (32.2%). In the meantime, the largest number of RAPD genotype-specific markers was generated for primers OPE-D-07(six markers) while for both of the OPE-B-17 and OP D-05 (two markers each). These markers can be verified as being RAPD markers associated with drought tolerance in the hibiscus genotypes that could help in marker-assisted selection breeding program.   Key words: Hibiscus, biomass production, osmotic adjustment, molecular markers, genetic polymorphism.