Tolerant Evaluation of Different Cultivars of Sunflower (Helianthus Annus L.) Against Drought Stress
This study showed the effects of drought on germination ability and growing of four sunflower genotypes: Alstar, Armaviresky, Haison25 and Uoroflour in laboratory and greenhouse. The experiment was conducted using factorial experiment based on a completely randomized design with four replications. In the laboratory, drought condition was induced by PEG 6000 at the same potentials of 0 (control), -0.2, -0.4, -0.6 and -0.8 MPa. In greenhouse drought condition was induced by using identify field capacity method with five levels 100 (field capacity), 85, 70, 55 and 40% of field capacity. Results revealed that germination percentage and rate, dry weight of hypocotyl and root, length and dry weight of plants and LAI decreased markedly in osmotic potential -0.6 and -0.8 MPa and at 55 and 40% of field capacity. A moderate water stress caused a marked increment in root growth. Also, among these varieties, Alstar and Haison25 were the most tolerant of drought stress.