Guanjun Huang

Although numerous studies have evaluated the effects of agronomic practices on either rice yield or grain quality, a comprehensive assessment of potential synergies and trade-offs between these traits across multiple management strategies remains limited, which is of great importance to simultaneously improving rice yield and quality in the future. In the present study, a meta-analysis was conducted with paired observations of rice yield and quality when various agronomic practices, including altering sowing date, alternate wetting and drying, growth regulator application, nitrogen application, potassium application, organic fertilizer application, increased planting density, silicon application, variety selection and zinc application, are employed. We found that applications of growth regulator and potassium fertilizer can improve rice yield, milling and appearance quality simultaneously. Enhanced rice yield and milling quality can be achieved through variety selection and organic fertilizer application. Additionally, enhanced rice yield and appearance quality can also be achieved through silicon application. However, though increased planting density and altered sowing date can improve rice yield and milling quality, they cause lower appearance quality. By contrast, though nitrogen application can improve rice yield and milling quality, it comes at the expense of appearance and eating quality. Therefore, our results indicate that there are indeed complex synergistic relationships and trade-offs between rice yield and various aspects of grain quality. Integrated agronomic technique packages should be employed to simultaneously improve rice yield and grain quality in the future.

Early-season rice in the middle and lower reaches of the Yangtze River is vital for China’s food security, but the planting area has sharply decreased in recent years due to its poor appearance and taste quality, as well as low returns. Therefore, we collected and analyzed 334 early-season rice varieties released in the region from 2000 to 2022. To verify whether low-amylose content (L-Am) varieties can reduce chalkiness without compromising yield, two field experiments were conducted: a two-year consecutive experiment (2021–2022) using six representative varieties (low amylose, L-Am: 14.5–16.8%; medium-high amylose, MH-Am: 23.8–25.9%), and a one-year validation experiment (2024) utilizing 32 widely cultivated varieties. The results indicated that the amylose content (AC) of the 334 varieties showed a normal distribution, with varieties containing 18–20% AC being the most prevalent (23.6%), which resulted in L-Am varieties collectively accounting for 46.4%; additionally, AC was significantly positively correlated with chalky kernel rate (CKR) and chalkiness degree (CKD), and negatively correlated with panicles per m² and length–width ratio (LWR), but showed no correlation with yield. Similarly, L-Am and MH-Am varieties achieved comparable yields through compensatory adjustments in field experiments: L-Am varieties had 12.8–13.9% more panicles per m² but 3.6–7.3% lower 1000-grain weight. Moreover, L-Am varieties exhibited superior grain quality, with 70.8–73.5% and 54.0–62.1% lower CKR and CKD, respectively. Physiological analyses revealed that L-Am varieties exhibited a smaller maximum grain-filling rate (GFR_max) and amylose accumulation rate (GAmR_max), mean grain-filling rate (GFR_mean) and amylose accumulation rate (GAmR_mean), longer active grain-filling/amylose accumulation periods (D), and higher activities of soluble starch synthase (SSS) during grain-filling stages. These results demonstrate that early-season rice varieties with low AC tend to exhibit significantly lower chalkiness. Physiologically, this superior appearance quality is strongly associated with maintained yield through compensatory yield components and distinct starch synthesis kinetics, offering a practical strategy for enhancing both quality and productivity in early-season rice.

BACKGROUND: Global warming has been suggested to have negative impacts on most quality traits of rice; however, factors and how they affect the responses of rice quality to warming still need systematic examination under field conditions.RESULTS: In this study, we conducted a meta‐analysis to evaluate the overall impacts of field warming on grain quality and identify the key factors affecting these impacts, collecting data from 45 published studies with 1316 paired observations. Our results found that warming significantly increased chalkiness degree, chalky rice rate, protein content and breakdown value, but decreased head rice rate and amylose content. Growth stage when warming was imposed had significant impacts on the grain quality responses to warming, with larger responses generally observed at reproductive stage than vegetative stage; besides, warming responses of grain quality also significantly differed among warming patterns and subspecies. Importantly, our results suggest that deterioration of appearance quality under warming tends to decrease with increasing soil fertility. However, with the increasing N and P applications and panicle N percentage, negative responses of milling and appearance qualities to warming become more severe. Additionally, our results suggest that negative responses of appearance quality to warming could be mitigated by increasing K application.CONCLUSION: Our present findings should further our understandings of the warming effects on rice quality under field conditions and be helpful in mitigating the negative effects of warming on grain quality by variety selection, amelioration of soil fertility and optimal inorganic fertilizer inputs. © 2025 Society of Chemical Industry.

The impacts of whole‐growth‐duration warming on grain yield and quality in a double rice cropping system remain largely unknown. In this study, a 2‐year field whole‐growth‐duration warming experiment was conducted with two inbred indica rice cultivars (Zhongjiazao 17 and Xiangzaoxian 45) for early season and two hybrid indica rice cultivars (Wanxiangyouhuazhan and Tianyouhuazhan) for late season, respectively. The results showed that whole‐growth‐duration warming did not affect early rice yield but significantly decreased late rice yield, which was caused by the decreased grain weight that may be related to the reduced translocation of dry matter accumulated during the pre‐heading phase under warming. Whole‐growth‐duration warming improved the milling quality of late rice but decreased that of early rice; however, the chalky rice rate and chalkiness degree were increased by 20.7% and 33.9% for early rice, and 37.6% and 51.6% for late rice under warming, respectively. We found that the crude protein content of milled rice was significantly increased by warming in both early and late rice, which would result in the deterioration of eating quality. Besides, compared with the control treatment, the setback of late rice was significantly reduced by 17.8% under warming, while that of early rice was not significantly affected by warming. These results suggest that the negative impacts of whole‐growth‐duration warming on grain quality varied between early rice and late rice to some extent. In summary, adaptation in both rice breeding and agronomic practices is needed to alleviate climate warming on the production of the double rice cropping system.

Improving the yield and quality for tasty rice varieties is a great challenge. In the present study, different nitrogen rates and plant density were utilized to form differential rice populational structures, which were determined to clarify key traits determining grain yield and quality for tasty rice varieties in a double-cropped rice system in subtropical China. The present results showed that the plant photosynthetic rate, leaf area index and plant respiration rate had important and significant impacts on the grain yields of both early and late rice, though the late rice yield was also significantly affected by the canopy temperature. In addition, among the studied populational traits, plant photosynthetic and/or respiration rates had significant effects on all quality traits. Consistently, grain yield and quality were significantly improved with the increasing plant photosynthetic and respiration rates through correlative analysis, which was also observed in principal components analysis. Overall, the present study suggests that both the grain yield and milling and appearance qualities could be improved through the optimal management of nitrogen and plant density through increasing plant photosynthetic and respiration rates.

Primary mechanism through which nanomaterials enhance plant photosynthesis.