Higher yield and grain quality adaptability of newly developed japonica rice cultivars under recent climatic variability in Central Korea: Evaluation with a quality climate adaptability index
¹Crop Research Division, Gyeonggi-do Agricultural Research and Extension Services, 283-33 Byeongjeomjungang-ro, Hwaseong-si, Gyeonggi-do 18388, Republic of Korea
²Plant Management & Research Division, Seoul Botanic Park, 161 Magokdong-ro, Gangseo-gu, Seoul 07789, Republic of Korea
*Correspondence: jjh7648@gg.go.kr
Abstract:
This study introduces and evaluates a Quality Climate Adaptability Index (QCAI) that integrates head rice ratio, protein content and palatability value to complement yield-centred assessment of rice cultivar adaptability under climatic variability. Five japonica rice cultivars –Chucheong, Daean, Samkwang, Chilbo and Chamdream – were evaluated under uniform cultivation conditions in Hwaseong, central Korea, from 2020 to 2025. The study period included contrasting grain-filling environments, particularly high temperature in 2024 and high precipitation with low solar radiation in 2025, allowing comparison of grain-quality responses across contrasting climatic conditions. In 2024, head rice ratio showed the most pronounced adverse response among the QCAI components, whereas no consistent deterioration of the three component traits was observed in 2025. Newly developed cultivars produced a higher mean milled rice yield than conventional cultivars (5.42 vs. 4.91 t ha⁻¹), and Chamdream and Samkwang ranked highest in yield-based climate adaptability. The annual group mean QCAI of newly developed cultivars was significantly higher than that of conventional cultivars (P = 0.0023). The two highest mean QCAI values were observed for Samkwang (0.65) and Chamdream (0.63), with no significant difference between them (P = 0.949); Chilbo was intermediate (0.01), whereas Chucheong (−0.60) and Daean (−0.69) were lower. These results indicate that QCAI complements yield-based assessment by integrating three representative grain-quality traits – head rice ratio, protein content and palatability value – into a measure of relative grain-quality performance under interannual climatic variability, while the stability of individual quality traits should be evaluated separately using extended multi-year data.
Key words:
climate adaptability, grain quality, head rice ratio, Oryza sativa L., palatability value, protein content