Comparative drought resistance in sunflower under controlled conditions [Articol]

Abstract

Under changing climatic conditions, sunflower (Helianthus annuus L.) cultivation is increasingly challenged by abiotic stresses such as drought. This study evaluates the response of three sunflower genotypes to osmotic stress induced by polyethylene glycol (PEG) at concentrations of 10%, 20%, and 30% during germination and early seedling development under controlled conditions. The germination rate was evaluated daily over a 10-day period. Seeds were exposed to PEG to assess germination rate, seedling growth, and stress tolerance indices. Genotype H3 demonstrated moderate tolerance, maintaining satisfactory germination at 10% PEG but showing a marked decline at higher concentrations. H1 was highly sensitive, with poor germination and severely restricted growth of 20% and 30% PEG. In contrast, H2 displayed strong resilience, maintaining consistent germination, root development even under severe stress. These highlight the genotypic variability in sunflowers drought tolerance and suggest that H2 is a promising candidate for cultivation in water-limited environments. H1 may be suitable under moderate stress, while H1 may require additional agronomic interventions. Overall, the selection of stress-resilient sunflower genotypes emerges as a key strategy for enhancing productivity in drought-prone regions.