Induction Somaclonal Variation in Pear Plants (Pyrus Communis var. Betulifolia) for Salinaty Tolerance Through Tissue Culture Technique.

SALINITY is one of the major environmental stresses that challenge …...plant growth and crop productivity worldwide. In the present investigation, an attempt to introduce tolerant pear rootstock was achieved. Callus of betulifolia were subjected to different concentration of sodium chloride as a source of salinity (1000 mg.L-1, 2000 mg.L-1, 3000 mg.L-1, 4000 mg.L-1 and 5000 mg.L-1) via in vitro culture technique. Survival calluses decreased in all of the tested concentrations, however, no survival calluses were obtained at 5000 mg.L-1. Moreover, regenerated plants were also decreased with the increasing of salt concentration. On morphological level, the 1000 mg.L-1 concentration revealed high measurement in compare to the control. The opposite was true for the 2000 mg.L-1, 3000 mg.L-1 and 4000 mg.L-1. Increment of salt concentration reduced both of the fresh weight and relative growth of fresh weight gradually from the 1000 mg.L-1 to 4000 mg.L-1.  Chemically, proline, sodium and chloride content were gradually increased with the increasing of sodium chloride concentrations. Meanwhile, salinity stress recorded drastic effect on chlorophyll content especially at 4000 mg.L-1, total chlorophyll content were decreased by the increasing of salt concentration. It could be recommended to examine the resistant plants with higher concentrations of salinity and grafted these plants by different cultivars of pear.