Identification of chlorophyll fluorescence parameters as biomarkers in dryland wheat for future climate conditions

Abstract Nowadays, climate change is the main factor that determines future food and nutritional security. To understand the interactive effects of climate variables on photosynthesis efficiency an experiment was carried out on 10 dryland wheat genotypes. Plants were exposed to the temperature (25 ± 3°C and 34 ± 3°C), carbon dioxide (380 ± 50 and 800 ± 50 ppm), and irrigation regimes (irrigation at 50% field capacity and well-watering). The obtained results revealed that the multiple effects of climate change variables reduced the maximal (Fm') and increased the minimal (Fo') fluorescence yield. In Sardari genotype, the effective quantum yield of photochemical energy conversion in PSII (Y(II)), photochemical quenching coefficient (qP), and the photochemical quenching coefficient of variable fluorescence (qL) increased, while the quantum yield of regulated energy dissipation in PSII (Y(NPQ)), the non-photochemical quenching coefficient (qN) and the non-photochemical quenching (NPQ) were reduced under both, single and interactive effects of studied variables. Elevated temperature reduced the Y(II) and led to quantum yield of non-regulated energy dissipation in PSII Y(NO) increment. PCA analysis showed that changes in NPQ were observed under temperature, Y(NO) under CO2, qL under irrigation, and qP and Y(II) under combined effects of climate change variables. Elevated CO2 reduced the ETR and gs of all genotypes. We conclude that monitoring qP and Y(II) efficiency parameters in dryland wheat can be used as suitable biomarkers in plant breeding programs related to adapted plant production to future climate conditions.