The collection of 10 parental lines of tetraploid wheat genotypes with various origin was cultivated in growth chamber. Leaf and growth traits such as assimilation pigments content, dry mass and leaf area of plants were measured. The genotype differences were recognized by chlorophyll a fluorescence fast kinetics method applied on penultimate young wheat leaves. Consequently, heat stress susceptibility based on the exposure of whole plants in pots to air temperature of 42oC for 6 hours was measured, too. Rapid chlorophyll a fluorescence kinetics method gave us better knowledge about differences among tetraploid wheat genotypes collection comparing to classic assimilation pigments analyse. Genotypes with higher content of pigments did not always exhibit good resistance against heat stress. Using the chlorophyll fluorescence parameters, the rating of genotypes based on photosynthetic performance as well as photosystem II (PSII) thermostability was done. We identified the genotypes TRG7 (Triticum turgidum subsp. turgidum, PI 384230, Ethiopia) and RONCAL (Triticum turgidum subsp. dicoccon, TRI 17700, Spain) as the perspective donors of genes for better thermostability of photosynthetic apparatus in changed climate conditions and material into wheat efficiency breeding programs.
