Effect of Aegilops speltoides Introgression on the Stability of Photosynthesis in Common Wheat under Different Water Supply

Introgression from wild cereals is widely used to transfer disease resistance genes into the common wheat genome, but information on its impact on other important traits under unfavorable climatic conditions is limited. We studied stability of photosynthesis under different water supply in two wheat lines with introgression from Aegilops speltoides. The plants were grown in a climate chamber under optimal water supply and simulated soil drought. Gas exchange and chlorophyll fluorescence were measured using a portable GFS-3000 system. Activity of four enzymes of antioxidant protection and lipoxygenase, as well as the content of photosynthetic pigments, free proline, and soluble sugars were measured spectrophotometrically. It was shown that translocations from Ae. speltoides in chromosomes 1, 5, and 6 of the B genome in the drought-sensitive cv. Rodina (line 73/00i) positively impacted photosynthetic process, increasing the maximum quantum yield of PSII photochemistry under drought. The introgression from Ae. speltoides into the 5BL chromosome of the drought-resistant cv. Saratovskaya 29 (line S29(73/00i 5B)) induced adaptive responses associated with the regulation of the redox balance and non-photochemical quenching of chlorophyll. However, they did not have a significant negative impact on the processes of photosynthesis during drought. Lines 73/00i and S29(73/00i 5B), which are known for their resistance to fungal diseases, can also be useful in breeding to improve wheat’s adaptability to water scarcity.