Effect of Bio-fortification of Zn and Fe on Nutrient Concentration, Uptake and Quality in Kharif Greengram (Vigna radiata L. Wilczek)

Abstract

Micronutrient deficiencies, particularly those of zinc (Zn) and iron (Fe), remain important nutritional concerns and                    contribute to hidden hunger. Greengram (Vigna radiata L. Wilczek) is a nutrient-rich pulse crop, and improving its Zn                     and Fe concentrations through agronomic biofortification may enhance its nutritional quality. Foliar and soil applications                     of Zn and Fe therefore offer practical approaches for increasing micronutrient accumulation in greengram grain. A field experiment was conducted during the kharif season of 2022 at the Research Farm of the Pulses Section, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar, to assess Zn and Fe biofortification in greengram (Vigna radiata L. Wilczek). The experiment was laid out in a randomised block design with 11 treatments and three replications. Treatments included the recommended dose of fertilisers (RDF), foliar applications of 0.5% ZnSO₄ and 0.5% FeSO₄ applied individually or in combination at the pre-flowering and pod-initiation stages, and soil application of ZnSO₄ at 25 kg ha⁻¹. Nutrient concentration, nutrient uptake, protein content, protein yield, and post-harvest soil nutrient status were evaluated. The combined foliar treatment of RDF + 0.5% ZnSO₄ + 0.5% FeSO₄ at both growth stages recorded the highest Zn content in seed (29.3 ppm) and straw (20.6 ppm), Fe content in seed (73.3 ppm) and straw (67.2 ppm), Zn uptake in seed (54.1 g ha⁻¹) and straw (71.1 g ha⁻¹), and Fe uptake in seed (135 g ha⁻¹) and straw (233 g ha⁻¹). It also recorded the highest protein content (22.1%) and protein yield (409 kg ha⁻¹). N, P, and K concentrations were not significantly affected by treatment, while uptake responses varied among nutrients and plant parts. Soil-applied ZnSO₄ produced the highest post-harvest available Zn (0.90 ppm). Under the study conditions, combined foliar Zn and Fe application at both reproductive stages produced the strongest overall micronutrient enrichment response.