Evaluation of Seaweed Application on Physiological Traits of Durum Wheat Landraces Under Drought Stress

Abstract

Drought stress is one of the major abiotic factors limiting wheat production worldwide and causes significant reductions in plant growth and physiological performance. Seaweed-based biostimulants have recently attracted considerable attention due to their potential role in improving plant tolerance against environmental stresses. This study was conducted to evaluate the effects of seaweed application on several physiological traits of durum wheat landraces exposed to severe drought stress under greenhouse conditions. Two cultivars and eight landraces, were used as plant material. Plants were grown under controlled greenhouse conditions and exposed to 80% drought stress at the tillering stage. A 2% seaweed extract was applied twice as foliar treatment during plant development. Physiological and morphological parameters were evaluated under drought conditions. The results demonstrated significant differences among genotypes and treatments for most investigated traits. Drought stress generally caused reductions in relative water content, SPAD values, plant height, flag leaf area, and biomass accumulation. However, several landraces maintained relatively higher physiological performance under stress conditions, indicating genotype-dependent variation in drought tolerance. Seaweed application partially alleviated the negative effects of drought in some genotypes by improving water status and chlorophyll preservation, whereas responses varied according to genotype and measured parameter. Overall, the findings indicate that durum wheat landraces possess considerable variability in physiological adaptation to drought stress and that seaweed-based applications may contribute to stress mitigation depending on genotype and environmental severity. The study provides useful information for future breeding programs aiming to improve drought tolerance in durum wheat and highlights the potential use of biostimulant applications under water-limited conditions.