Drought tolerance evaluation of bread wheat (Triticum aestivum L.) lines with the substitution of the second homoeological group chromosomes

Bread wheat spring cultivar Saratovskaya 29 (S29) is a highly drought tolerant. S29, five single chromosome substitution and two introgression lines of this cultivar for chromosomes of second homoeological group were grown in a climatic chamber under optimal and water deficit conditions of water supply. The donor of the three homologous chromosomes 2A, 2B and 2D was the German spring cultivar Yanetskis Probat; the donors of chromosome 2D were the old spring varieties of Western Siberia, Caesium 111 and Sibirka 1818. The donors of 2A chromosome were the species Triticum timopheevii and Aegilops markgrafii. Eleven physiological indexes including water use efficiency, the chlorophyll a, chlorophyll b and carotenoids contents, osmotic substances contents, antioxidant enzymes activities and lipoxygenase activity were measured in leaves of wheat at the stage of beginning of earing. To assess genotypes, we established a comprehensive evaluation value (D) based on various measured physiological parameters and shoot biomass. The D positively correlated with the tolerance of shoot biomass (r = 0.955, P < 0.001) and was reduced in four of seven lines with a modified genome. The least stable were the line with the introgression from Aegilops markgrafii in 2A chromosome and the line with the substitution of 2D chromosome of the recipient for the homoeologous chromosome from Sibirka 1818. All lines changed the adaptation strategy compared to the recipient variety. The accumulation of a large amount of soluble sugars in the leaves of lines was the largest difference between them and the recipient S29.