Biofortification-Based Genetic improvement of Rice for Nutritional Quality Enhancement to Combat Hidden Hunger

Abstract

Micronutrient malnutrition, particularly deficiencies of iron, zinc, and provitamin A, remains a major global public-health challenge, with rice-consuming populations being disproportionately affected due to the inherently low nutrient density of polished rice grains. Biofortification has emerged as a sustainable, cost-effective, and long-term strategy to enhance the nutritional quality of rice, complementing conventional supplementation and food-fortification programs. This review synthesizes the current advances in genetic enhancement of rice for improved nutritional traits, emphasizing both conventional and modern breeding approaches. Progress in identifying quantitative trait loci (QTLs), high-zinc and high-iron donor lines, and key genes regulating micronutrient accumulation is discussed, along with the integration of marker-assisted selection, genomic selection, and transgenic interventions such as overexpression of metal transporters, nicotianamine biosynthesis genes, and provitamin A pathways. Recent breakthroughs using genome editing technologies, particularly CRISPR/Cas systems, have accelerated precision improvement for micronutrient content without compromising yield or grain quality. The review also highlights physiological constraints, bioavailability challenges, genotype × environment interactions, and regulatory considerations associated with biofortified varieties. Future opportunities focus on leveraging pangenomics, multi-omics integration, speed breeding, and gene pyramiding to develop next-generation biofortified rice. Overall, biofortification stands as a promising strategy to combat hidden hunger, and continuous innovation in breeding and biotechnology is critical for delivering nutritionally enhanced rice cultivars to vulnerable populations worldwide.