Evaluating Seedling-Stage Salinity Resilience in Bangladeshi Wheat (Triticum aestivum L.) Cultivars via Multivariate and Physiological Profiling

Abstract

Soil salinity constrains wheat establishment, particularly during germination and early seedling development. This study evaluated the morphological, physiological, and biochemical responses of four wheat cultivars—BARI Gom 33, BARI Gom 28, BARI Gom 26, and BARI Gom 22—exposed to salinity levels of 0, 4, 8, and 12 dS m⁻¹ under controlled conditions. The experiment was arranged in a completely randomised design with three replications. Germination percentage, shoot and root length, fresh and dry biomass, SPAD-based relative chlorophyll content, Na⁺ and K⁺ concentrations, the Na⁺/K⁺ ratio, and proline content generally increased. SPAD values also varied among salinity treatments and cultivars, but these measurements should be interpreted as indicators of relative chlorophyll content rather than as measures of direct photosynthetic efficiency. Among the evaluated cultivars, BARI Gom 22 showed comparatively better performance under the highest salinity treatment, maintaining 51.67% germination; shoot and root lengths of 8.35 and 5.17 cm, respectively; a Na⁺/K⁺ ratio of 0.398; a proline content of 4.37 μmol g⁻¹ FW; and a SPAD value of 59.52. Correlation, principal component, and hierarchical clustering analyses demonstrated clear associations among growth, ionic, and biochemical traits across salinity treatments. Overall, the results indicate comparatively greater seedling-stage salinity tolerance in BARI Gom 22 among the four cultivars evaluated. Further field-based assessment is required to determine whether this response is maintained through later developmental stages and ultimately translates into improved grain production under saline conditions.