Screening of sunflower (Helianthus annus L.) accessions under drought stress conditions, an experimental assay

Drought is the major abiotic stress that limits the crop production at drastic level. Screening of tolerant accessions from available germplasm is the basic step in plant breeding. Sunflower is becoming popular and major oilseed crop in world but unfortunately it is drought sensitive. Screening in field has uncertainties due to the uncontrolled conditions, interaction of biotic and abiotic stresses and variability in environmental factors. Response of the sixty sunflower accessions to drought stress at germination and seedling stage was examined by using polyethylene glycol (PEG-6000) as drought simulator under laboratory. Normal and drought stress treatments i.e. T-1 = zero (control), T-2 = -1.33 MPa and T-3 = -1.62 MPa were developed by dissolving 0, 15 g and 20 g Polyethylene Glycol (PEG-6000) in 100 mL distilled water and a completely randomized design with three replications were used. Promptness, germination, seedling height, fresh weight, dry weight and stress indexes were determined to evaluate the response of sunflower accessions under normal and PEG simulated drought stress treatments. Principal component analysis was used to select the drought tolerant and sensitive accessions. The accessions 017583, A-75, A-79, 017592, G-33, A-48, A-23, G-61, HBRS-1 and 017566 were selected as drought tolerant while, CM-621, 017577, HA-124, HA-133, HA-342 and HA-341 were as drought sensitive. This study may be helpful for the comparison of drought indexes in a controlled experimental assay and for the identification of drought tolerant sunflower cultivars to be used in further breeding programs.