POSSIBLE IMPROVEMENT TOWARDS SALT TOLERANCE IN EMS MUTATED STRAWBERRY (Fragaria x ananassa Duth.) FESTIVAL CULTIVAR

Abstract

The present study was established to enhance NaCl tolerance in strawberry (Fragaria x ananassa Dutch) ‘Festival’ cultivar which is grown widely in Iraq and it is sensitive to salt stress, Leaf explants were treated with Ethyl Methane Sulfonate (EMS) to induce genetic variation and then used for callus induction and shoot regeneration under NaCl stress. Different concentrations of NaCl (0.0, 10, 25, 35 or 45 mM) were dissolved with irrigation water and added to the soil. Response to NaCl was evaluated after three months. Callus cultures were initiated on Murashige and Skoog (MS) medium supplemented with different concentrations of α-naphthalene acetic acid (NAA) and 6- benzylaminopurine (BAP), 4 mg/L-1 NAA+1 mg/L-1 BAP. The regenerated shoots were inoculated on shoot induction medium containing 2 mg/L1 BAP + 0.5 mg/L-1 NAA then transferred to MS medium supplemented with IBA 1.0 mg/L-1 for rooting. Morphological parameters, number of leaves, plant height, vegetative area, number of flowers, number of fruits and weight of fruits were investigated compared with in vivo plants. Genetic variation based on RAPD- PCR technique was used to detect variability. The results showed a high reduction in shoots regeneration and rooting in response to increasing NaCl. Morphological characteristics decreased in response to increase NaCl concentrations as well. However, in vitro regenerated plants derived from leaf discs treated previously with EMS, exhibited better performance in these parameters than in vivo plants at high concentrations of NaCl. Using eight RAPD primers a total number of 15 unique bands resulted after EMS treatment in Festival, while 3 unique bands appeared under NaCl stress. This study revealed that EMS as a chemical mutagen is a promising in enhancing NaCl tolerance.