Improved Processing Quality in a <i>tongil</i>-type Waxy Rice Cultivar Associated with a Rare <i>granule-bound starch synthase I</i> Allele

Research on <i>tongil</i>-type rice has aimed to enhance genetic diversity and yield through <i>indica</i>-japonica hybridization; however, poor eating quality remains a limitation in Korea. We evaluated three high-yielding <i>tongil</i>-type waxy cultivars, focusing on the allelic variation in the <i>granule-bound starch synthase I</i> (<i>GBSSI</i>) gene and its effects on quality traits. Physicochemical properties, including texture and retrogradation, were assessed using a texture analyzer, and pasting properties were analyzed using a Rapid Visco Analyzer (RVA). ‘Hanareumchal’ showed the softest texture (1.70 Kgf) and the slowest retrogradation rate. Genetic analysis revealed a unique <i>Wx-g2</i> allele derived from Japanese waxy rice (‘Odorokimochi’), which likely underlies these favorable traits. RVA profiling further <i>indica</i>ted reduced viscosity parameters, supporting its suitability for processed rice products that require extended shelf life and texture stability. These findings highlight the role of <i>Wx-g2</i> in improving <i>tongil</i>-type waxy rice and provide useful insights for breeding programs targeting enhanced processing performance.