Evaluation of gene expression and enzymatic and biochemical activities of leaves in native and foreign genotypes of bread wheat before and after anthesis

Wheat flag leaf plays a valuable role in the production of dry matter, and the transfer of photosynthetic material to the grain and related physiological properties such as chlorophyll content and photosynthetic efficiency are important factors in increasing yield. This experiment was carried out in Golestan province, in a randomized complete block design (RCBD) with four replicates. Wheat genotypes included N-91-9, N-91-17, Tiregan, Nogal, Euclide, Agorazado, Lucullus, and Antonius. Sampling from flag leaf and other leaves was done at 10 stages included 7 DBA (day before anthesis), 3 DBA, anthesis, 3 DAA (day after anthesis), 7 DAA, 11 DAA, 15 DAA, 19 DAA, 23 DAA, and 27 DAA, and the samples were carried to laboratory in liquid nitrogen and stored at -80 ℃. Part of the leaf samples was carried with a paper bag and incubated in an oven at 80 ℃ for 48 hours. Biochemical traits such as chlorophyll content, net photosynthetic rate, sucrose content, sucrose synthase (SS), sucrose phosphate synthase (SPS) content, grain yield, and photosynthetic genes expression including RbcL, RbcS, and Rca were measured in all stages. Results showed that flag leaf in the post-anthesis stages has a significant role in photosynthesis and sucrose production in the plant and cultivars with higher chlorophyll content also had higher photosynthesis. Also, in genotypes with higher SS enzyme activity, more sucrose was synthesized and due to the role of SPS, increasing this parameter was involved in the transfer of sucrose from leaves to other organs. The RbcL, RbcS, and Rca genes had higher expression in cultivars with higher photosynthesis than the control (Tiregan). Among the studied genotypes, Nogal cultivar and line N-91-17 was superior in terms of grain yield and other measured traits and can be recommended for use in future research.