Effects of Salinity Stress on Growth Parameters of Soybeans (Glycine max) Cultivated in Obubra Local Government Area, of Cross River State Nigeria

Soybean (Glycine max) is a strategic crop plant grown to obtain edible oil and forage. High sensitivity is one of the biggest problems with soybean crop. A pot experiment was conducted in the screen house at the Cross River University of Technology, Obubra Campus to investigate the effects of different salt concentrations on the growth parameters of three different varieties of soybeans (Glycine max). The experiment was laid in complete randomized design (CRD) with twenty replicates for each variety. Growth parameters which include germination percentage, plant height, number of leaves and number of branches per plant were measured, and 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 showed that salinity stress led to a significant reduction in percentage of germination, plant height, number of leaves, and number of branches per plant over control. At 30mM NaCl which was the highest level of saline water TGX 1987-10F had a better germination percentage as compared to other varieties, which might be because of some salt tolerant genes. Plant height reduced significantly under salinity stress as compared with the control, but TGX 1835-10F at 30mM which was the highest saline treatment showed a better salt tolerance level as compared with other varieties. Number of leaves per plant, as the salinity levels increases it affected the number of leaves. There was a drastic reduction in the number of leaves with increasing salinity levels as compared with the control. TGX 1987-10F had the highest number of leaves and it was closely followed by TGX 1835-10E while 1448-2E was the least and there were significantly different from the ones at different salinity levels. The result revealed highly significant differences (p=0.05) in the varieties, with TGX 1987-10F as the best variety appropriate for saline regions. It is therefore recommended that, TGX 1987-10F should be cultivated in saline regions since it showed a better tolerance level as compared to other varieties.