Growth Performance of Soybeans Varieties in a Salt-affected Site in Yala, Nigeria

Abstract

A pot experiment was conducted in Okpoma, Yala Local Government Area of Cross River State, to assess growth parameters of ten different varieties of soybeans cultivated in salt mining site. Growth parameters which include plant height, number of leaves and number of branches across three salinity levels (4,6 and 8 dS/m). The experiment was laid in a Completely Randomized Design (CRD), with three replicates for each variety. Data collected were subjected to statistical analysis using Analysis of Variance (ANOVA) and means were compared using Duncan’s New Multiple Range Test (DNMRT). The result demonstrated that, increasing salt concentration negatively influenced soybeans plant height with the degree of impact varying among varieties.  Varieties like TGX 1987-62F and TGX 1987-10F tend to maintain relatively higher heights under saline conditions, suggesting better salt tolerance. The overall, results for number of leaves underscore a clear negative correlation between salt stress and vegetative growth, as evidenced by leaf number. The variability among varieties indicates inherent genetic differences in salinity tolerance, with some genotypes like TGX 1987-10F and TGX 1904-6F demonstrating better resilience. The data clearly demonstrated that, salinity stress significantly diminishes the number of branches in soybean varieties over time, with the degree of impact varying among genotypes. Varieties like TGX 1987-62F and TGX 1987-10F show promising resilience, maintaining higher branch numbers even at elevated salt concentrations, making them suitable candidates for cultivation in saline environments. These findings revealed that salinity significantly reduced plant height (up to 42% reduction at 8 dS/m), and number of leaves (up to 47%), and number of branches (up to 50%) compared to control conditions. The results also highlighted the importance of selecting and breeding soybean varieties with inherent tolerance traits to mitigate the detrimental effects of soil salinity on vegetative development and crop productivity.