Tolerance of Seven Faba Bean Varieties to Drought and Salt Stresses

Abstract

Abstract: Seven varieties of faba bean (Vicia faba L.), one of them is Egyptian origin and the other six varieties were provided by ICARDA, were investigated for evaluating their drought and salt tolerance. Faba bean plants were grown under three different irrigation water intervals, 5, 10 and 15 days and two concentrations of NaCl, 25 and 50mM. Control plants showed higher growth and yield than plants subjected to water or salt stress. Control plants of the seven varieties arranged by yield follow the order: V5, V6, V3, V2, V1 and V4. Variety 4 exhibited significant stimulation of yield under salinity effect of the adopted concentrations, thus this variety has the highest salt tolerance of the seven studied varieties. Expose the faba bean varieties (1, 2, 4, 5, 6 and 7) to water stress leads to significant increase in photosynthetic pigments after 45days from sowing, this effect inversed after 90 days. Salt stress commonly reduce chlorophyll but increase carotenoids in plant leaves. The photosynthetic pigments of variety 3 leaves increased by water and salt stresses. Salinized plants showed the highest values of total soluble sugars, proline and total free amino acids. Highest records of total soluble sugars of the seven varieties of control plants were exhibited by varieties 5, 6 and 1. Higher values of total soluble sugars were recorded for varieties 1, 7 and 3 under 25mM and varieties 6, 5 and 1 under 50 mM NaCl. Variety 3 showed the highest amounts of proline under water and salt stresses. Variety 2 showed the highest values of total free amino acids under water stress and V2, V5 and V1 under 50 mM NaCl. The dendrogram obtained by application of clustering analysis on the reduction percentage values in the yield as a result to water and salt stresses, appeared that varieties; 4, 6 and 3 are more drought tolerance, and varieties 4 and 3 are more salt tolerant than the other varieties.