Evaluation of Salinity Tolerance on New Selected Almond × Peach Hybrid Rootstocks

The main objective of this investigation was to evaluate the determination effect of salt tolerance of five new almond× peach hybrid rootstocks namely hybrid 1, 2, 3, 4 and 5 through their vegetative growth parameters and chemical concentrations. This evaluation aimed to recommend these rootstocks for the commercial use. This experiment was carried out at the Horticulture Research Institute, Agriculture Research Center, Giza, Egypt, during two successive seasons (2018-2019 and 2019- 2020) respectively. Rootstocks chosen for this study included new almond× peach rootstocks which are resistant to nematode. Salinity irrigated water included four levels of NaCl salt which was 500, 1000, 1500, 2000 ppm and the control which was the usual irrigated water. Results cleared that increasing salinity levels led to reduction in all growth parameters including seedling stem diameter, heights, average leaves number and buds per one, leaf area, fresh and dry weights. High salinity levels declined gradually mineral concentrations like N, P, K, Mg%, Fe and Mn ppm. Moreover the highest level of salinity conducted to the highest level of Na and Cl ppm concentrations. Chlorophyll values take the same trend while proline values take the opposite trend with high salinity due to it considered an indicator to high salinity. Moreover, there were differences between rootstocks to salinity tolerance. Hybrid No.5 was the most resistant hybrid to high salinity concentration followed by hybrid No.4 while hybrid No.3 was the least one. Hybrid No.5 reached the highest values of growth parameters and it shared with hybrid No.4 the highest values of N, P and K, Mg concentrations and the highest levels of Fe, Mn, Na and Cl. Chlorophyll values take the same trend with slightly differences with hybrid No.4. On the other hand hybrid No.3 was the least hybrid in all growth measurements, mineral concentration and chlorophyll except proline concentration it recorded the highest value. From the above investigation we can recommend hybrid number5 or hybrid number4 which had the best results compared to other seedlings rootstock under experiment salinity conditions.