Influence of iron seed priming on seed germination, growth and iron content in rice seedlings

The area under direct-seeded aerobic rice (DSR) is increasing in Indo-gangetic plains due to labor and water scarcity. However, iron (Fe) deficiency is a severe problem in DSR under coarse-textured soils, resulting in poor germination, interveinal chlorosis, and poor seedling establishment. Fe seed priming is a better option to ensure higher seed germination and optimum supply of Fe at initial growth stages. Hence, the experiment was conducted with seven seed priming treatments i.e. Control (hydropriming), 0.5% Fe through ferrous sulfate (FeSO4 7H2O), 1.0% Fe through FeSO4 7H2O, 0.25% Fe through ethylene diamine tetra acetic acid chelated iron (Fe-EDTA), 0.5% Fe through Fe-EDTA, 0.025% Fe through iron oxide nanoparticle (FeO NPs) and 0.05% Fe through FeO NPs. The Fe seed priming showed a significant increase in Fe content of paddy seeds over the hydropriming treatment. Among different treatments, FeSO4.7H2O (1.0% Fe) showed highest germination percentage (91.3%), root length (8.4%) and shoot length (9.4%) followed by FeSO4.7H2O (0.5% Fe) which was significantly higher over the control. But, the treatment involving Fe-EDTA (0.5% Fe) showed adverse effects on germination and seedling growth. Ferrous (Fe2+) iron and total Fe content in rice seedlings showed similar trends to total Fe content in primed seeds treated with different Fe sources. Thus, Fe seed priming of rice with FeSO4.7H2O (1.0%Fe) for 12 h was effective for higher germination percentage, greater iron content at initial growth stages and ameliorated the Fe deficiency in direct seeded aerobic rice.