Oligomeric proanthocyanidins (OPCs) are abundant polyphenols found in foods and botanicals that benefit human health, but our understanding of the functions of OPCs in rice plants is limited, particularly under cold stress. Two rice genotypes, named Zhongzao39 (ZZ39) and its recombinant inbred line RIL82, were subjected to cold stress. More damage was caused to RIL82 by cold stress than to ZZ39 plants. Transcriptome analysis suggested that OPCs were involved in regulating cold tolerance in the two genotypes. A greater increase in OPCs content was detected in ZZ39 than in RIL82 plants under cold stress compared to their respective controls. Exogenous OPCs alleviated cold damage of rice plants by increasing antioxidant capacity. ATPase activity was higher and poly (ADP-ribose) polymerase (PARP) activity was lower under cold stress in ZZ39 than in RIL82 plants. Importantly, improvements in cold tolerance were observed in plants treated with the OPCs and 3-aminobenzamide (PARP inhibitor, 3ab) combination compared to the seedling plants treated with H₂O, OPCs, or 3ab alone. Therefore, OPCs increased ATPase activity and inhibited PARP activity to provide sufficient energy for rice seedling plants to develop antioxidant capacity against cold stress.

Rice is one of China’s primary staple crops, serving as the main food source for over 60% of the population. With the resolution of basic food security issues in China in recent years, the demand for high-quality rice has been steadily increasing. The taste quality of rice, a crucial indicator for evaluating rice quality, has attracted more attention from consumers. Although factors like variety, growing environment, and cultivation methods affect rice taste quality, the underlying mechanisms remain unknown, and no reliable control methods exist. This study selected 10 major rice cultivars, including 6 indica and 4 japonica varieties, and compared their differences in taste quality, focusing on yield and its components, taste quality, and dry matter accumulation. Among the tested varieties, Songxiangjing 1018 had the best taste quality, but not the highest yield. Zhongzheyou 8, Huazheyou 261, and Quanyousimiao showed both excellent taste quality and high yield. There was no significant correlation between taste quality and yield, suggesting the feasibility of breeding rice varieties with both superior taste and high productivity. Correlation analysis indicated that dry matter mass and net photosynthetic rate were significantly positively correlated with yield, but not with taste quality, highlighting the complexity of taste quality formation. Using a membership function comprehensive evaluation method (combines the outputs of multiple membership functions into a single composite value using specific rules (e.g., weighted average, extremum, logical operations) to produce a new membership degree.), a rice variety selection system balancing yield and quality was constructed, and three varieties (Zhongzheyou 8, Huazheyou 261, and Quanyousimiao) were identified as having both high yield and excellent quality. The results of this study can provide a theoretical basis for research on cultivation techniques and variety breeding aimed at synergistically improving rice yield and quality.