WATER STRESS EFFECT ON PHYSIOLOGICAL, MORPHOLOGICAL PARAMETERS AND THE YIELD OF FIVE SUNFLOWER CULTIVARS (Helianthus annuus L.) GROWN UNDER GREENHOUSE

Sunflower (Helianthus annuus L.) is one of the world’s major oilseeds species however, it faces the problem of summer drought which coincides with the end of its cycle inducing yield decrease. The aim of this study is to identify morpho-physiological traits that can be used as selection criteria in hybridization programs for stress tolerance. In this context, a greenhouse essay has been carried out using five oleic sunflower genotypes arranged in a randomized complete block design with two water regimes; water regime 2:100% of field capacity and water regime 1:30% of field capacity. The obtained results show that water stress affects many measured parameters such as relative water content, stomatal conductance, stem diameter and yield components (seed number per head and 100-seed weigh). Genotype effect was significant for stomatal conductance, number of leaves per plant and yield components. However, the effect of the genotype x water regime interaction was significant only for the number of leaves per plant, yield and seed number per head.