Morphological and Productivity Characteristics of Tobacco Varieties as Influenced by Potassium Humate (k-humate) and Sorbitol under Drought Stress Conditions

The experiment was carried out in a completely randomized block design (RCBD) with three replications, at the Scientific Agricultural Research Station (Setkhiris-Latakia), using seedlings of three tobacco varieties (Virginia VK51- Burley R21 - Katrina) and treating them with concentrations (0- 5- 15 %) of polyethylene glycol (PEG-600) and foliar spraying with a concentration of 0.5 g/L of potassium humate (k-humate) and sorbitol. The aim of this research was to determine the response of some morphysiological and productivity characteristics under the effect of the most harmful level of drought stress induced by PEG-600 and spraying with potassium humate and sorbitol. The drought stress (PEG 5 %), as well as foliar spraying with 0.5 g/L of potassium humate and sorbitol, led to a significant increase in plant height (cm), plant leaves area PLA (cm2/plant), leaf area index (LAI), crop growth rate CGR (g/m2/day) and weight of dry leaves (g/plant). While drought stress (PEG 15 %) caused a significant decrease in the values of all the studied traits. A significant increase in the studied traits compared to the PEG 5 and 15 % treatments alone was recorded when plant foliar sprayed with potassium humate and sorbitol. Thus, it can suggested application treatment with PEG 5 %, foliar spraying with potassium humate (k-humate) or sorbitol at a concentration of 0.5 g/L to stimulate plant growth and reduce the damaging effects of drought stress.