Response of alfalfa genotypes to saline water irrigation

The influence of saline water (4, 8, 12 dS m(-1)) irrigation on gas exchange and growth response of alfalfa genotypes Anand-2, T-9 and IL-112 was studied. T-9 and IL-112 showed a significant increase in net photosynthetic rate (P-N) at low salinity (4 dS m(-1)) compared to the control whereas Anand-2 maintained an unaltered P-N Reduction in P-N at higher salinities was primarily due to reduction of stomatal conductance. There was a greater reduction in transpiration rate as compared to P-N rate, which resulted in an increase in water use efficiency (WUE). High WUE may serve as one of the strategies of the plant to withstand saline environment. However, the slight increase in WUE in Anand-2 could not help in maintaining its growth. Increase in Na+ concentration in comparison to K+ concentration may also contribute to the inhibition in growth.