Comparison of physical and chemical properties of medium-grain rice cultivars grown in California and Arkansas

ABSTRACT:  The physical attributes, chemical composition, and physicochemical properties of 2 medium-grain rice cultivars from Arkansas (Bengal, Medark) and from California (M202, M204) were compared when grown in their respective locations and grown together in Arkansas to better understand the impacts of heredity and environment on medium-grain rice quality. Variations existed in grain dimensions, particularly length distribution, among cultivars and between crop years. When grown separately, the Arkansas cultivars tended to have higher protein and lipid contents but lower amylose contents than the California cultivars. M204 contained a significantly higher apparent amylose content (21.0%) compared with the other 3 cultivars (14.3% to 16.4%). The Arkansas rice cultivars exhibited higher pasting and gelatinization temperatures and produced harder gels and less sticky cooked rice. However, when the 4 cultivars were grown together in Arkansas, differences in protein and amylose contents, gelatinization and pasting properties, and cooked rice texture decreased. This study demonstrated that genetics, location, and crop year all contributed to variations in rice chemical and physical characteristics.