Effects of potassium application on growth of peanut (Arachis hypogaea) and ionic alteration under saline irrigation

A field experiment was conducted during the summer seasons, of 2011 and 2012 at Junagadh, Gujarat, to evaluate the ameliorative effect of potassium in salinity tolerance of peanut (Arachis hypogaea L.). Treatments included 2 differentially salt-responsive cultivars (‘GG 2’ and ‘TG 37A’) and 3 levels of salinity (control, 2.0 dS/m, 4.0 dS/m) along with 2 levels of potassium fertilizer (0 and 30 kg K₂O/ha). Supplementary application of potassium resulted in improved salinity tolerance in terms of growth (plant height, branches, root length and weight); yield attributes (100-pod and kernel weight and shelling %); yields (pod, kernel and haulm yield) and Na⁺: K⁺ ionic ratio in (shoot, root, leaf and kernel). Cultivar ‘GG 2’ showed better salt tolerance by excluding sodium from uptake although cultivar ‘TG 37A’ allowed more sodium to accumulate in all the peanut parts (root, shoot, leaf and kernel), hence showed more susceptibility to salinity stress. Further about 3–4 times higher sodium was accumulated in root over shoot, leaf and kernel. External application of potassium resulted in nullifying the harmful effect of salinity stress with slightly better response in the susceptible cultivar ‘TG 37A’ as compared to cultivar ‘GG 2’.