Changes in biochemical compositions and salinity tolerance responses of different bread wheat varieties cultivated in an arid and semi-arid climate

The present study aimed to investigate the differential responses of several wheat cultivars under saline conditions through two complementary experiments, a laboratory-based Petri dish test and a field trial. Therefore, the effects of salinity levels (control, 4, 8, and 12 dS.m ^− 1 ) were firstly studied on seed germination indices and some growth-related parameters of six bread wheat cultivars/new promising lines (e.g., cultivars of Chamran-2, Mehrgan, Marvdasht, and Narin, as well as new promising lines of MS-89-13 and MS-90-13) using a factorial based on the completely randomized design in the Petri test for ten days in three replications. Subsequently, different responses of the superior cultivars/lines selected were evaluated under both normal and saline field conditions through a combined analysis using a randomized complete block design, conducted over the 2020–2021 and 2021–2022 growing seasons with three replications. The Petri data showed that salinity levels negatively influenced germination indices, with the highest germination percentage, optimal T50 values, longest shoot length, and highest leaf protein content observed under the control (non-saline) treatment across all cultivars. Among cultivars, the Chamran-2 cultivar achieved the highest germination percentage, shoot length, and leaf protein content, and the lowest T50 value. Additionally, the minimum values of root length and root length stress tolerance index traits were observed for the interaction of MS-89-13 promising line×12dS.m ^− 1 salinity level. Field experiment data revealed that the highest values for plant height, 1000-grain weight, grain and biological yields, pigment contents, grain protein, wet gluten, and gluten index were recorded in plants grown under normal conditions during the second year of the study. Chamran-2, and then Mehregan had more proper conditions and had longer plants, heavier grain weight, and higher grain and biological yields. However, the maximum values for wet gluten and gluten index were obtained for Mehregan and Narin cultivars, respectively. The highest straw yield was obtained under the Chamran-2 cultivar×Normal farm×Second year interaction. The highest catalase activity was recorded for saline conditions and the first year of the experiment, and the highest superoxide dismutase activity was observed for the Narin cultivar×Saline conditions×Second year interaction. Eventually, considering the predominant characteristics of the farm experiments, Chamran-2 and Mehrgan cultivars can be cultivated in the southern regions of Iran and similar areas as a reference.