Zinc Seed Coating Improves Emergence and Seedling Growth in Desi and Kabuli Chickpea Types but Shows Toxicity at Higher Concentration

Chickpea is very sensitive to zinc (Zn) deficiency that can be corrected by Zn application in several ways to various crops including seed coating. However, the optimization of Zn seed coating in chickpea is needed prior to its wide application under field conditions. This study was comprised of four experiments in petri plates and sand filled pots for optimization of Zn seed coating concentration in desi and kabuli chickpea types. In first two experiments, Zn was applied using different seed coating concentrations viz., 5, 50, 100 and 200 mg Zn kg-1. No Zn was taken as control. High Zn concentrations (100 and 200 mg Zn kg-1) indicated Zn toxicity and inhibited the seed germination. In third and fourth experiments, Zn was applied at 5, 20, 35 and 50 mg Zn kg-1 with non-coated seeds as control. These studies were carried out in sand filled pots and petri plates. In petri plates, seeds were uniformly spread between the two layers of moist filter paper while seeds were sown in small sand filled (500 g) pots. In experiments, emergence/germination rate, emergence/germination index, root and shoot lengths improved with Zn seed coating (5 mg Zn kg-1). Moreover, seedling dry weight and number of secondary roots per plant in both chickpea types (desi and kabuli) improved with Zn seed coating at 5 mg Zn kg-1 compared with other Zn seed coating concentrations. However, Zn seed coating above 5 mg kg-1 suppressed the germination/emergence and seedling growth of both chickpea types indicating Zn toxicity. In conclusion, seed coating with 5 mg Zn kg-1 was best treatment in improving the emergence/germination and early seedling growth in both chickpea types.