Can be performance indexes used to select plant growth-promoting rhizobacteria?

The plant growth-promoting rhizobacteria (PGPR) are bacteria that colonize the rhizosphere or roots, resulting in a beneficial effect on plants. The evaluation of the PGPR effects is mostly based on growth biometric measurements, but there is little information about using the chlorophyll (Chl) fluorescence. We used rhizobacteria to treat canola seeds and evaluate their effects on leaf area, dry mass, and Chl fluorescence. In order to select PGPR, we suggest the JIP-test as a method to evaluate their effects using the performance indexes. The biometric measurements and JIP-test parameters allowed to group bacterial isolates into different groups. We observed that some PGPR increased the energy absorption efficiency/or flux. We conclude that the performance indexes can be used to differentiate the interaction of plants and PGPR and to select rhizobacteria with a potential for plant growth promotion.