Determining the Tolerance of Selected Almond Rootstock Genotypes to Salt Stress Under in vitro Conditions

The research was carried out to determine the salt stress tolerance status of some almond genotypes considered as rootstock candidates under in vitro conditions. The genotypes were cultured in the MS nutrient medium containing 0, 50, 100 and 150 mM NaCl. Apart from NaCl, 1.0 mg/l BAP, 0.01 mg/l IBA, 30 g/l sucrose and 7 g/l agar were added to the nutrients and the pH was adjusted to 5.7. In vitro shoots were incubated for 4 weeks in a climate room with 16-h light and 24 degrees C temperature, and then the number of shoots per explant, the proline, chlorophyll, total phenolics, total flavonoids and total protein contents, superoxide dismutase, CAT and APX enzyme activities were evaluated. In parallel with the increase in salt stress level, it was determined that the number of shoots and chlorophyll contents decreased significantly in all genotypes as compared to the control treatment. The proline, total phenolic, total flavonoid and total protein contents and enzyme activities increased significantly with the increase in the salt level. In the study, no significant difference was observed regarding the tolerance status of the genotypes in the MS medium containing 50 mM NaCl. Considering the 100 and 150 mM NaCl applications, it was determined that the genotypes numbered 9, 29, 54, 120, 134, 183, 185, 196 and 241 showed better development and therefore they stood out in terms of salt tolerance as compared to the other genotypes.