Impact of Salinity on Tolerance, Vigor, and Seedling Relative Water Content of Haricot Bean (Phaseolus Vulgaris L.) Cultivars

A laboratory experiment was undertaken to evaluate the impact of salinity on seedling tolerance and vigor indices, phytotoxicity, and relative water content of haricot bean cultivars. Two haricot bean cultivars (Lehade and Chercher) and five salinity levels (0, 2, 4, 8, and 16mM) were factorialy arranged in Completely Randomized Design with three replications. The result of the study revealed that no significant interaction effect between cultivars vs salinity treatments (p<0.05). However, cultivars differ significantly (p<0.05) on seedling and root vigor indices, shoot phytotoxicity, and relative water content of shoot and root. Lehade gave higher seedling, shoot and root vigor indices; whereas, Chercher gave relatively higher seedling tolerance index, and lower shoot and root phytotoxicity. The highest relative shoot and root water contents were recorded on Chercher compared to Lehade. The increase in NaCl concentrations significantly (p<0.05) decreased seedling, shoot, and root vigor indices; and the lowest vigor indices were observed on 16mM NaCl concentration. However, the phytotoxicity of shoot and root increased as the concentrations of NaCl increased; and the lowest value of phytotoxicity observed at control treatment and 2 mM, while the highest on 16mM. Significant negative relationships were observed between relative shoot (R2 = 0.896) and root (R² = 0.904) water contents, and salinity concentrations. In conclusion, cultivars varied genetically for their tolerance, and relative water content. The increase in salinity decreased vigor and tolerance indices, and relative water content; however increased phytotoxicity percentage of root and shoot of haricot bean.