Transgene escape could lead to genetically modified rice establishing wild populations in the natural environment and competing for survival space with weeds.  However, whether the expression of the Bacillus thuringiensis (Bt) gene in rice will alter the relationship between transgene plants and weeds and induce undesirable environmental consequences are poorly understood.  Thus, field experiments were conducted to investigate the weed competitiveness and assess the ecological risk of transgenic Bt rice under herbicide-free and lepidopterous pest-controlled environments.  Results showed that weed–rice competition in the direct-sowing (DS) field was earlier and more severe than that in the transplanting (TP) field, which resulted in a significant decrease in biomass and yield in DS.  However, conventional Bt and non-Bt rice yield was not significantly different.  The weed number, weed coverage ratio, and weed diversity of conventional Bt rice were significantly higher than those of non-Bt rice at the early growth and mature stages, especially in DS plots, suggesting that Bt traits did not increase the weed competitiveness of transgenic rice and had no negative effect on weed diversity.  Grain yield and weed number varied between different hybrid rice lines, but those differences were insignificant between Bt and non-Bt rice.  The number of insects increased with the increase of weeds in hybrid rice plots, whereas the insect number and diversity did not display a significant difference between Bt and non-Bt rice.  Therefore, the ecological risk of transgenic Bt rice is comparable to non-Bt rice.

Geographical indication (GI) rice refers to the rice of specific geographical origin, which tends to have a good taste quality and a high commodity price.  Rice is favored for its soft texture and chewiness after cooking.  However, GI rice is also plagued by rice fraud.  Understanding the reasons for the excellent taste quality of GI rice and identifying its geographical origin can help maintain the stability of the rice market and promote the development of the rice industry.  In this study, we determined the taste quality of rice.  Untargeted metabolomics based on UHPLC–Q-Exactive-MS was used to identify metabolites in GI and regular rice before and after cooking.  Our findings suggested that GI rice showed lower protein and amylose content, resulting in higher starch gelatinization properties and taste quality.  This study identified 520 metabolites, among which 142 and 175 were significantly different between GI and regular rice, before and after cooking, respectively.  The increased variety of metabolites after cooking was significantly negatively correlated with the taste quality of rice.  GI rice was lower in amino acids and lipid metabolite content before and after cooking, which may be the reason for the excellent taste quality.  Through linear discriminant analysis, we found that the differential metabolites of rice after cooking were more accurate in discriminating rice from different geographic origins, up to 100%.  This work gained new insights into the metabolites of GI rice, which explains its excellent taste quality.  The rice metabolites after cooking could be used for more accurate geographical identification of rice.

Rice grain yield and quality declines are due to unsuitable temperatures from wide regions and various sowing dates.  This study aimed to evaluate the effects of temperature on rice yield and quality at different phenological periods and obtain suitable temperatures for phenological periods in the Yangtze River Basin, China.  This study conducted experiments on different sowing dates under different areas in the Yangtze River Basin to observe and compare the differences in rice growth, yield, and quality, controlling for regional varieties.  The results showed significant differences in rice growth, yield, and quality among sowing dates and areas, which were related to the average daily temperature during the vegetative period (VT) and the first 20 days of the grain-filling period (GT20).  In addition, there was a smaller variation in the average daily temperature in the reproductive period (RT) than in the two phenological periods.  Therefore, according to the VT and GT20 thresholds of different yields and qualities, the experimental results were divided into four scenarios (I, II, III, and IV) in this study.  In Scenario I, high head rice production (rice grain yield multiplied by head rice rate) and rice quality could be obtained.  The head rice production of Scenarios III and IV was lower than that of Scenario I, by 30.1 and 27.6%, respectively.  In Scenario II, the head rice production increased insignificantly while the chalky grain rate and chalkiness were 50.6 and 56.3% higher than those of Scenario I.  In conclusion, the Scenario I combination with VT ranges of 22.8–23.9°C and GT20 ranges of 24.2–27.0°C or the combination with VT ranges of 23.9–25.3°C and GT20 ranges of 24.2–24.9°C, which can be obtained by adjusting sowing date and selecting rice varieties with suitable growth periods, is recommended to achieve high levels of rice grain yield and quality in the Yangtze River Basin. 

The developmental capacity of in vitro embryos is critical for the success of embryonic biotechnology. However, in vitro embryos often exhibit suboptimal quality, with fewer inner cell mass (ICM) cells and reduced total blastocyst cell counts compared to in vivo embryos. To address this, we optimized the conventional PZM-3 culture medium by supplementing 50% Advanced DMEM/F12 and 5% FBS on the fifth day after embryo activation (Day 5 medium) and resulted in a 2.5-fold increase in the total cell numbers of parthenogenetic activation (PA) derived blastocysts. Further enhancement was achieved by incorporating Activin A in Day 5 medium, creating the OIVC (Optimized In Vitro Culture) medium, which significantly increased both the total cell numbers and the ICM cell counts by 4.5-fold in the blastocyst stage. The OIVC medium also improved the quality of pig somatic cloned and in vitro fertilized (IVF) embryos. RNA sequencing analysis revealed that in the OIVC-treated embryos, most of the differentially expressed genes were downregulated compared to the control group, with the main enriched signaling pathways including Activin A/TGF-β. Notably, among these downregulated genes, PAX6 may be as a potential key gene influencing the number of ICM cells. This study presents a novel culture system that markedly enhances pig in vitro embryo quality, providing an efficient strategy for generating cloned pigs based on somatic cell nuclear transfer (SCNT) technology.