Comparative Studies of Chlorophyll Concentration on Different Varieties of Soybeans Treated with Different Levels of Salinity in Salt Mining Site, in Yala Local Government Area, Cross River State, Nigeria

Abstract

Salinity is a major abiotic stress limiting soybean productivity, particulary in salt-affected regions. A pot experiment was conducted in Okpoma, Yala Local Government Area of Cross River State, to compare the impact of increasing salinity levels (0, 4, 6 and 8 dS/m-1) on chlorophyll concentration of different varieties of soybeans cultivated in salt mining site over at 12-week period. The experiment was laid in a Completely Randomized Design (CRD), with three replicates for each variety. Data collected was subjected to statistical analysis using Analysis of Variance (ANOVA) and means were compared using Duncan’s New Multiple Range Test (DNMRT). The results revealed a significant decline in chlorophyll content with rising salinity, with sensitive varieties such as TGX 1904-6F and TGX 1905-2F showing early and severe pigment degradation. In contrast, salt-tolerant varieties like TGX 1987-10F and TGX 1448-2E retained higher chlorophyll levels, suggesting presence of adaptive physiological mechanisms including osmotic adjustment, ion homeostasis, and antioxidant defense. These findings highlight chlorophyll content as a reliable physiological indicator for salt stress tolerance and support its inclusion in breeding programs aimed at improving soybean resilience in saline environments.