Chlorophyll fluorescence in different wheat genotypes grown under salt stress

To assess the genotypic variation for efficiency of photo-system-II (Fv/Fm) in wheat genotypes containing introgression from chromosomes 1D, 3D and 5D of Aegilops tauschii and whether it could be used as a selection criteria for salt tolerance, 32 wheat genotypes were grown under field conditions and subjected to varying levels of salinity stress (10, 15 and 20 dS m^-1). For most of the wheat genotypes, we observed Fv/Fm value greater than 0.8 at higher salinity levels compared to that of control. The minimum value of 0.8 for the efficiency of PSII (Fv/Fm) shows the health and vigor of the plant. A lower value indicates that a proportion of PSII reaction centers are damaged, a phenomenon called photo-inhibition, often observed in plants growing under stress conditions. Although salt stress reduced grain yield in all wheat genotypes, it is not positively associated with F_v/F_m. In conclusion, F_v/F_m can not be referred as a selection criterion for salt tolerance in wheat genotypes examined in the present study.