Yield, Stability, and Adaptability of Hybrid Japonica Rice Varieties in the East Coast of China

The high yield potential and stability of hybrid japonica rice varieties are crucial for sustainable agricultural development and food security. Rice varieties must undergo rigorous testing through multi-site regional trials before being introduced to the market in China. The assessment of these regional trials is essential for guiding rice breeding. In this study, we evaluated the yield performance of 13 hybrid japonica rice genotypes (g1–g13) across six regional trial sites (e1–e6) in Jiangsu province, China. Variance analysis revealed that genotype (G), environment (E), and genotype-by-environment (G × E) interactions significantly influenced the yield of hybrid japonica rice varieties. The effects of G × E interactions on the yield potential and stability of these tested rice varieties were further analyzed using Genotype plus Genotype-by-Environment interaction (GGE) biplot and additive main effects and multiplicative interaction (AMMI) model analyses. The results reveal that Zhegengyou2035 (g4) and Changyou20-2 (g3) exhibited superior yield potential and stability, while Huazhongyou9413 (g12) exhibited broad adaptability. Additionally, the assessment of discrimination and representativeness among regional trial sites revealed that the Wujin Rice Research Institute (e6) served as an optimal testing location. Our findings identify the most suitable rice varieties for the area and assess their potential as initial material in the selection processes for breeding new varieties. Additionally, this work contributes to the strategic selection of optimal testing locations.