Agronomical and Physiological Responses of Faba Bean Genotypes to Salt Stress

Considering the importance of salinity stress and genotype screening under stress conditions, the current study evaluated faba bean genotypes in response to saline stress and identified those that were tolerant and determined the influential ratio of each yield component on seed yield under both conditions. As a result, 12 faba bean genotypes were tested under 2 levels of salt stress (100 mM and 200 mM) and a control. The study was analyzed with multivariate (descriptive, ANOVA, PCA, biplot, cluster analysis, and indices) analysis techniques to determine the tolerance level of each genotype. Similarly, the cluster analysis results reported that faba bean genotypes were divided into two groups under the control and 100 mM salinity levels; however, the 200 mM salinity level recorded three groups of faba bean genotypes, showing that salinity stress may limit phenotypic variability among faba bean genotypes. The descriptive analysis results showed a wide range of diversity among the studied characteristics under control and salinity stress conditions. The number of seeds/plants recorded a significant association with plant height (cm) (PH), stomatal conductance (SC), days to flowering (DF), the number of pods, and seed weight (g) (SW); however, an insignificant association was recorded with leaf temperature (LT), fresh weight (g) (FW), Na⁺, K⁺, and Na/K ratio. The first three principal components (PCs) represent 81.45% of the variance among the studied traits. The most significant characteristics that contributed the most to the diversity were (PH, leaf area, SPAD reading, stomatal conductance, DF, number of pods/plants, number of seeds/pods, SW, K, and total chlorophyll content); however, the significant genotypes (Hassawi-2, Sakha, ILB-4347, Misr-3, FLIP12501FB) were present in PC1 under both conditions. The results predicted that Hassawi-2, ILB-4347, Sakha, Misr-3, and Flip12501FB were the significant (tolerant) genotypes. However, FLIP12504FB represents a sensitive genotype based on its final grain yield. The results of the indices also recorded significant index correlations with grain yield, demonstrating that these indices are effective tools for screening faba bean-tolerant genotypes under salinity stress conditions.