Performance of selected North African barley genotypes based on agro-morphological and physiological traits under field conditions in Morocco

Abstract

As climate change accelerates, the impact on barley production, particularly in water-limited regions, is becoming more pronounced. This study assesses the physiological and agronomic responses of nine barley genotypes from Morocco, Egypt, and Tunisia under rainfed conditions across two growing seasons (2021 and 2022) in northwestern Morocco. The aim was to evaluate the vulnerability of Mediterranean barley and identify drought-resistant genotypes by analyzing key physiological traits and adaptive capacities under varying precipitation levels. A comprehensive analysis was conducted, focusing on morphological traits (peduncle length, PL; flag leaf area, FLA), physiological traits (canopy temperature depression, CTD; transpiration rate, E; chlorophyll content, SPAD; total chlorophyll; chlorophyll fluorescence, F v /F m ), and agronomic performance (grain yield, GY; plant height, PH; harvest index, HI; shoot dry weight, SDW). ANOVA results showed that genotype origin was the primary source of variation for several traits (59-90% of total variability), while the growing season significantly affected CTD, PL, HI, and E (>60% of the variation). Tunisian genotypes exhibited higher drought sensitivity, with a 43% reduction in GY, whereas Moroccan genotypes showed moderate resilience with a 7% decrease. Egyptian genotypes demonstrated the highest stability. Principal Component Analysis (PCA) confirmed a clear distinction between tolerant and sensitive genotypes, as well as a differentiation between the climatic conditions of the two growing seasons. Stepwise regression analysis revealed that RWC was the most influential trait for GY variability, explaining 76% of its variation in 2021 and 92% in 2022, while CTD contributed an additional 9% in 2021.