Using chlorophyll fluorescence parameters and antioxidant enzyme activity to assess drought tolerance of spring wheat

The improvement of phenotyping methods is necessary for large-scale screening studies of wheat (Triticum aestivum L.) drought tolerance. The objective of our research was to find out whether it is possible to use chlorophyll (Chl) fluorescence parameters instead of biochemical indicators of drought tolerance when screening wheat. We measured shoot biomass, gas exchange, as well as biochemical and Chl fluorescence indicators in 11 wheat genotypes grown under contrasting water supplies and differing in drought tolerance. The effect of drought on the traits was evaluated using the effect of size index. We made two independent rankings: one based on biochemical indicators and the other on Chl fluorescence parameters. The positions of the three genotypes with the highest comprehensive drought tolerance index in the two independent rankings coincided completely. It is concluded that Chl fluorescence methods are suitable for identifying soft wheat genotypes that differ significantly in their ability to activate cellular defense mechanisms.