Comparative Efficacy of Different Rice (Oryza sativa L.) Genotypes for Improved Zinc and Iron Uptake and Relevant Yield Efficiency under their Foliar Application

Over half of the world's population relies on rice for their daily diet and suffers from hidden hunger. This study aimed to enhance zinc (Zn) and iron (Fe) concentrations in rice grains through biofortification strategies, evaluating the impact of foliar Zn and Fe applications on various rice genotypes. Pot experiment was conducted using eleven different rice genotypes and consisted of two different treatments where foliar application of Zn (0.5% w/v) and Fe (0.2% w/v) at the flowering and booting stages were compared with control (no Zn and Fe application). Pots were arranged by following completely randomized design (CRD) under 2-factor factorial arrangement. The efficiency indices for Zn and Fe grain yield and their uptake efficiencies were measured to classify genotypes based on their responsiveness and efficiency under low Zn and Fe levels (control). Zn and Fe grain yield efficiency indices ranged from 94.3 to 70.5% and 86.6 to 35.3%, respectively, while their uptake efficiencies were 75.0 to 43.9% for Zn and 72.6 to 37.1% for Fe. Genotypes ZJ-34, ZJ-11, and ZJ-14 were "efficient and responsive," while ZJ-23 and ZJ-19 were "efficient and non-responsive" for Zn. YR-28, ZJ-29, and ZJ-26 were "inefficient and responsive," and YR-3, YR-5, and YR-7 were "inefficient and non-responsive." Similar classifications were observed for Fe, with genotypes such as ZJ-11 and ZJ-34 showing superior performance. Efficient genotypes (e.g., ZJ-11 and ZJ-34) exhibited better performance under control and responded positively to fertilization, underscoring their potential in biofortification. Additionally, genetic modifications could integrate traits from inefficient but responsive genotypes, contributing to sustainable solutions for combating hidden hunger.