Unlocking Low-glycemic Potential in Rice: Genetic Insights and Breeding Strategies.

Rice (Oryza sativa L.) is a staple food consumed by billions worldwide, yet its high glycemic index (GI) poses health risks, including type II diabetes, obesity, and cardiovascular diseases. The GI of rice is primarily influenced by starch composition, particularly the amylose-to-amylopectin ratio, as well as resistant starch. Understanding the genetic basis of GI and leveraging advanced breeding techniques can facilitate the development of low-GI rice varieties, which offer significant health benefits while maintaining essential agronomic traits. This review examines the genetic determinants influencing GI, focusing on key genes such as Waxy (Wx), Starch Synthase IIa (SSIIa), and Granule-Bound Starch Synthase (GBSS), which regulate starch biosynthesis and composition. It also explores cutting-edge breeding strategies, including CRISPR/Cas9 gene editing, RNA interference (RNAi), and genome-wide association studies (GWAS), as tools for enhancing amylose content and resistant starch, thereby reducing starch digestion rates and minimizing postprandial glucose spikes. Globally, efforts to develop low-GI rice are expanding beyond traditional breeding hubs. Research initiatives in China, Japan, India, Thailand, and the Philippines are actively working toward breeding nutritionally optimized rice varieties tailored for diverse dietary needs and the management of metabolic disorders. Given the rising prevalence of diabetes and lifestyle-related diseases worldwide, the development of low-GI rice holds immense potential for improving public health, supporting functional food markets, and enhancing food security. This review aims to provide a comprehensive perspective on genetic factors and innovative breeding approaches for developing low-GI rice varieties across different global rice-growing regions, contributing to sustainable agricultural and nutritional advancements.