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IntroductionIn recent years, with the rapid expansion of ratoon rice production in Hunan, a unique ratoon rice-based production system, forage-grain ratoon rice (FG-RR), has been newly developed. Ratooning rice is a season of rice harvested by utilizing the dormant buds on the rice stubble left after harvesting the first season of rice to sprout and grow. Therefore, the characteristics of stalks themselves are crucial for the production of ratoon rice. The cutting period and higher stubble height directly affect the characteristics of ratoon rice stubbles. Based on this, we conducted the following research.MethodsIn 2021 and 2022, field experiments were conducted in central China to study the effects of different cutting periods and stubble height on the regeneration rate and nutrient content of ratoon crops. The treatments included two cutting periods (10 days after heading in the first season and 30 days after heading in the first season, respectively referred to as T10 and T30) and two stubble heights (10 cm and 30 cm, respectively referred to as H10 and H30).ResultsCompared with the T30H30 treatment, T10H10 and T10H30 increased grain yield by 48.1%, 41.7%, 73.1%, and 65.2% in the two-year ratoon seasons, while T30H10 reduced grain yield by 30.9% and 19.5% in the two years, respectively. Early cutting increased the panicles, spikelets per panicle, and filled grain rate to varying increase, while higher stubble height increased panicles but decreased spikelet panicle. On the one hand, early cutting and higher stubble height increased the dry and fresh weight, nonstructural carbohydrates (NSCs), organic carbon (C), and nitrogen content of rice stalks, thereby improving the regeneration rate of ratoon rice. On the other hand, early cutting and higher stubble height retention increased the accumulation of nitrogen in rice stubble throughout the entire growth period and facilitated the transport of nitrogen to the mature panicles.DiscussionTherefore, appropriate early cutting and higher stubble height retention are the keys to improving the grain yield and stability of ratoon rice.

As the largest rice production province in China, the ratoon rice in Hunan has rapidly developed in recent years in the aspects of planting area, total production, and cultivation technologies. The present review is undertaken to summarize the past and current status and the key practices of ratoon rice production in Hunan. The planting area of ratoon rice in Hunan was 267,000 ​ha in 2019, with the average yield of 7.50–10.50 ​t ​ha−1 and 2.30–6.00 ​t ​ha−1 in the main and ratoon seasons, respectively. The grain quality in ratoon season is similar to or even better than that of late-season rice, but the relatively poor grain quality in the main season limits the profits for farmers. In recent years, research on the cultivation technology of ratoon rice has been widely conducted in Hunan, which led to the development of a series of key practices for ratoon rice production with regard to variety selection, sowing dates, crop establishment, fertilizer and water management, straw cutting height and harvesting time, and the controls of pests, diseases, and abiotic stresses. However, the constraints in policy intervention, as well as the large yield gap, have greatly limited the further expansion of ratoon rice in Hunan. To further promote ratoon rice production in Hunan, the innovation and extension of fully mechanized ratoon rice cultivation technologies, breeding and chemical regulation approaches to enhance ratooning ability, and support from the local government regarding policy, infrastructure, demonstration, and training must be strengthened in the future.

Mycotoxins often contaminate rice, which are the secondary metabolites of fungi. Ustiloxins, a type of mycotoxin that has often been overlooked, pose a significant risk to human health. Therefore, identifying and controlling the pollution of ustiloxins in rice is required. In this study, we examined the natural contamination of rice with ustiloxins and their link to climate conditions. A total of 300 paddy samples were collected from six regions in southern China, and concentrations of ustiloxins A, B, C, D, and F were analyzed by liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results showed that the occurrence of ustiloxins A, B, C, D, and F in paddies was found to be 55.7%, 41.3%, 29.0%, 93.7%, and 96.7%, respectively. Ustiloxin A had the highest mean (177.8 µg/kg) and maximum (3620.9 µg/kg) concentration, followed, in order, by ustiloxins C, B, D, and F. Furthermore, ustiloxin levels were significantly different depending on their origin, with the highest concentration in rice from Changde and Yueyang. And the regional difference in ustiloxins was related to the diversity of climate. A positive correlation between ustiloxin occurrence and mean humidity and precipitation was found in July and August of different regions, while mean temperature indicated a negative dependence. This is an essential survey of the contamination of rice with ustiloxins throughout southern China. The influence of climatic conditions on ustiloxins contamination was evaluated for the first time in our study. Overall, the rice samples examined in this study exhibited a high distribution of ustiloxins, suggesting that regulatory limits and the establishment of maximum allowable levels of ustiloxins in rice are necessary. This study provides a basis and guidance for the pollution situation and control strategy of ustiloxins in China.

IntroductionSeed priming is a pre-sowing seed treatment that is beneficial for rice seed germination and seedling growth, but the reduced seed longevity after seed priming greatly limited its adoption. The deterioration of primed seeds showed large differences among different studies, and the priming method might play an important role in regulating the deterioration speed of primed seeds. However, whether and how the priming method affected the deterioration of primed rice seeds during storage remains unknown. MethodsIn this study, two typical seed priming methods, namely hydropriming (HP) and osmopriming (PEG) were compared under artificially accelerated aging conditions, the changes in germination performance, starch metabolism, seed respiration and reactive oxygen species accumulation before and after accelerated aging were determined.Results and discussionHydroprimed rice seeds exhibited significantly faster deterioration speed than that of PEG-primed seeds in terms of germination speed and percentage. Meanwhile, α-amylase activity and total soluble sugar content in hydroprimed seeds were reduced by 19.3% and 10.0% respectively after aging, as compared with PEG-primed seeds. Such effects were strongly associated with the increased reactive oxygen generation and lipid peroxidation, as the content of superoxide anion, hydrogen peroxide and malondialdehyde in hydroprimed seeds were 4.4%, 12.3% and 13.7% higher than those in PEG-primed seeds after aging, such effect could be attributed to the increased respiratory metabolism in hydroprimed seeds. In addition, the simultaneous use of N-acetylcysteine with HP and PEG priming greatly inhibited the deterioration of primed rice seeds, suggesting that the ability to scavenge reactive oxygen species may be the key factor affecting the speed of deterioration in primed rice seeds during storage.

Abstract In present study, sodium salt of α-naphthalene acetic acid (NA), potassium salt of fulvic acid (KF) and their combinations were applied to the growth substrates of tomato seedlings (Solanum lycopersicum L.) under chilling stress. The changes in aboveground biomass, root attributes, pigment contents, chlorophyll fluorescence, photosynthesis, osmotic regulation substances, and antioxidant enzymes activity of the tomato seedlings in response to NA and KF were investigated. The application of NA, KF and their combination could promote the growth of plant height and stem diameter of tomato seedlings under chilling stress to varying degrees, and improve root characteristics by increasing root volume, root length and root activity, and increase dry matter accumulation. In addition, the combined use of NA and KF improved the seedling leaf chlorophyll content, qP, Fv/Fm, ΦPSII , Pn and increased the activity of antioxidant enzymes in the tomato plants. The above results suggested a synergistic effect between NA and KF to stimulate the seedlings growth and to enhance the ROS scavenging ability of tomato, which has never been reported in previous research before. However, further researches are needed to explore the physiological and molecular mechanism underlying the synergistic effect between NA and KF.

Forage–food dual-purpose ratoon rice cropping (FFRR) is used to balance forage demands with ratoon rice grain yields, that is whole plant (stem and sheath, panicles) cuttings in the main season are used as forage, and rice in the regeneration season is used as food. In this study, the local ratoon rice production system as the control, we were carried out the field experiment of cultivation practices (cutting time and cutting height), and investigated the system productivity, economic benefits, carbon footprints and energy use efficiency. The energy use efficiency, energy productivity and energy profitability increased with cutting time delay, and cutting height decreased. Significant differences of these index were observed among the treatments for cutting time and cutting height (p

The purpose of this study is to determine the effects of red and blue lights on the photomorphogenesis and photosynthetic traits of rice seedlings. The rice seedlings were cultured with red light (R), blue light (B), combined red and blue lights (R3B1/R1B1/R1B3), and white light (CK) as the control. The combined application of red and blue lights could promote the growth of rice seedlings to varying degrees; enhance photosynthesis by increasing the seedling leaf area, chlorophyll content, and chlorophyll fluorescence; improve root characteristics by increasing root number, root volume, and root activity; and thus increase the dry matter accumulation of rice seedlings. In addition, the combination of red and blue lights could regulate the expression of genes related to photosynthesis in rice leaves, affect the activity of the Rubisco enzyme, and then affect the photosynthesis of rice seedlings. These results indicate that red and blue lights have direct synergistic effects, which can regulate the growth of rice seedlings and promote the morphogenesis of rice seedlings. The combined application of red and blue lights can be used to supplement the light in rice-factory seedling raising.

Abstract The uniformity of the rice cluster distribution in the field affects population quality and the precise management of pesticides and fertilizers. However, there is no appropriate technical system for estimating and evaluating the uniformity at present. For that reason, a method based on unmanned aerial vehicle (UAV images) is proposed to estimate and evaluate the uniformity in this present study. This method includes rice cluster recognition and location determination based on the RGB color characteristics of the seedlings of aerial images, region segmentation considering the rice clusters based on Voronoi Diagram, and uniformity index definition for evaluating the rice cluster distribution based on the variation coefficient. The results indicate the rice cluster recognition attains a high precision, with the precision, accuracy, recall, and F1-score of rice cluster recognition reaching > 95%, 97%, 97%, 95%, and 96%, respectively. The rice cluster location error is small and obeys the gamma (3.00, 0.54) distribution (mean error, 1.62 cm). The uniformity index is reasonable for evaluating the rice cluster distribution verified via simulation. As a whole process, the estimating method is sufficiently high accuracy with relative error less than 0.01% over the manual labeling method. Therefore, this method based on UAV images is feasible, convenient, technologically advanced, inexpensive, and highly precision for the estimation and evaluation of the rice cluster distribution uniformity. However, the evaluation application indicates that there is much room for improvement in terms of the uniformity of mechanized paddy field transplanting in South China.

The present study investigated the effects of different integrated cultivation treatments on the yield, nitrogen agronomic efficiency (AEN), and growth performance of a ratoon rice system. A two-year field experiment was carried out during 2021–2022 using a randomized block design. Cultivation treatments included the farmers’ practice model (control, CK), high-yield and high-efficiency model (T1), enhanced-high-yield and high-efficiency model (T2), and the no-N model (N0). The grain yield, yield components, root traits, and stubble characteristics were determined. The results showed that T2 treatment significantly increased the grain yield and AEN by 53% and 236%, respectively, compared with CK. Similarly, the stubble weight, non-structure carbohydrate contents, and the root attributes were significantly improved under T2 treatment. The correlation analysis suggested that ratoon rice yield and AEN was significantly and positively correlated with root weight (p < 0.01) and the stubble parameters including stubble weight (p < 0.01), starch content (p < 0.01), and soluble sugar content (p < 0.01). Additionally, a significant and positive correlation between root weight and stubble weight (p < 0.05) was determined in our study. Consequently, our work highlights the benefits of integrating planting density, nitrogen/water management, and other practices to achieve high AEN and grain yield of the ratoon rice by improving root trait and stubble characteristics of the main rice.

The purpose of this study is to determine the effect of light quality on growth, carbon and nitrogen metabolism, and antioxidant defense system of rice seedlings. Six light conditions were employed, including white (W), red (R), blue (B), combined LED of R and B at 3:1 (R3B1), combined LED of R and B at 1:1 (R1B1), as well as combined LED of R and B at 1:3 (R1B3). Combined application of red light and blue light could promote the growth of rice seedling leaves and roots under low light stress to varying degrees, increase the photosynthetic area by increasing the leaf area, improve the root characteristics by increasing the root volume, and increase the dry matter accumulation of rice seedlings. In addition, the combination of red light and blue light could increase carbon and nitrogen metabolites in rice seedling leaves, regulate the expression of genes related to carbon and nitrogen metabolism and enzyme activity, and enhance the antioxidant enzyme activity of rice seedlings. These results indicate that red light and blue light directly have synergistic effects which can regulate the carbon and nitrogen metabolism of rice seedlings, promote the morphogenesis of rice seedlings under low light stress, and promote growth, which has never been reported in previous studies. This study is a new discovery in the application of light quality in crop production and provides new avenues to enhance crop stress resistance. However, further study is needed to explore the physio-biochemical and molecular mechanisms of light quality in crop production.

The diagnosed COVID-19 cases revealed that the incubation periods (IP) varied a lot among patients. However, few studies had emphasized on the different clinical features and prognosis of patients with different IP. A total of 330 patients with laboratory-confirmed COVID-19 were enrolled and classified into immediate onset group(IP10 days, L group, 75 cases) based on IP. The difference of clinical characteristics and prognosis of the two groups were compared. There were more patients with fever in I group than in L group(P = 0.003), and counts of all the total lymphocytes, total T lymphocytes, CD4 + and CD8 + T lymphocytes were significantly different between the two groups(all P

Abstract Background The novel coronavirus disease 2019 (COVID-19) broke out globally. Early prediction of the clinical progression was essential but still unclear. We aimed to evaluate the timeline of COVID-19 development and analyze risk factors of disease progression. Methods In this retrospective study, we included 333 patients with laboratory-confirmed COVID-19 infection hospitalized in the Third People’s Hospital of Shenzhen from 10 January to 10 February 2020. Epidemiological feature, clinical records, laboratory and radiology manifestations were collected and analyzed. 323 patients with mild-moderate symptoms on admission were observed to determine whether they exacerbated to severe-critically ill conditions (progressive group) or not (stable group). We used logistic regression to identify the risk factors associated with clinical progression. Results Of all the 333 patients, 70 (21.0%) patients progressed into severe-critically ill conditions during hospitalization and assigned to the progressive group, 253 (76.0%) patients belonged to the stable group, another 10 patients were severe before admission. we found that the clinical features of aged over 40 (3.80 [1.72, 8.52]), males (2.21 [1.20, 4.07]), with comorbidities (1.78 [1.13, 2.81]) certain exposure history (0.38 [0.20, 0.71]), abnormal radiology manifestations (3.56 [1.13, 11.40]), low level of T lymphocytes (0.99 [0.997, 0.999]), high level of NLR (0.99 [0.97, 1.01]), IL-6 (1.05 [1.03, 1.07]) and CRP (1.67 [1.12, 2.47]) were the risk factors of disease progression by logistic regression. Conclusions The potential risk factors of males, older age, with comorbidities, low T lymphocyte level and high level of NLR, CRP, IL-6 can help to predict clinical progression of COVID-19 at an early stage.

Developing an efficient and high-yielding mechanical rice establishment system is one of the most important approaches for intensive and large-scale rice production. Recently, an orderly mechanical rice seedling throwing system (OMST) was successfully developed; however, the performance of this system is unknown. In the present study, a two-year field experiment was carried out in a split-plot design with three establishment methods arranged in the main plots, and two elite rice cultivars arranged in the sub-plots. The grain yield and growth-related traits were then determined. The results showed that the grain yield of OMST was significantly higher than manual seedling throwing, and was equivalent to that of manual transplanting, which was mainly due to the variances in panicle number and total spikelet number. Further analysis suggested that the orderly mechanical seedling throwing takes advantage of higher biomass accumulation after heading, increased leaf area index and decreased leaf senescence rate against manual seedling throwing, and more tillers and biomass accumulation at vegetative growth stage as compared to manual transplanting. The present study showed that the OMST is an efficient and high-yielding rice establishment method that may be a promising option to replace traditional manual seedling throwing in rice production.

The development of varieties with strong tolerance is one of the important strategies to diminish the negative impact of chilling stress during heading on the spikelet fertility and yield formation of late-season rice. However, whether such genetic improvement has been made in inbred late rice lines in China is not clear. In the present study, three late-season inbred rice varieties, Xiangwanxian2 (XWX2, released in 1988), Xiangwanxian8 (XWX8, released in 1998) and Xiangwanxian17 (XWX17, released in 2008) were subjected to moderate (20 °C) and extreme (17 °C) chilling stress during heading, and the grain yield components and flowering-related traits of the three varieties in response to different temperature were investigated. The results showed that the newly released inbred late rice variety XWX17, demonstrated better chilling tolerance during heading than the early released varieties with respect to higher grain filling percentage. The improved grain filling percentage in XWX17 might be the results of increased spikelet fertility, which was attributed to the increase in pollen viability, anther dehiscence length and anther volume. In addition, the SPAD value and the chlorophyll a content of the flag leaf can be used as indicators to predict the rice spikelet fertility when suffering from chilling stress during heading. The present study provides evidence that the genetic approach has been made to improve the chilling tolerance of inbred late rice lines during heading; however, further research is needed to explore the physiological and molecular mechanism underlying the relationship between leaf characteristics and function with rice spikelet fertility.

No-tillage (NT) management is considered a leading approach for sustaining crop production and improving soil and environmental quality. Based on a long-term no-tillage experiment in a rice–oilseed rape cropping system, we examined differences in soil organic matter (SOM), soil microbial carbon (C) and nitrogen (N) content, and methane (CH4) and carbon dioxide (CO2) fluxes between NT and conventional tillage (CT) management. SOM under NT was 21.0 g kg–1, and a significant difference was detected between 2004 and 2016. SOM increased under NT and CT by averages of 0.60 and 0.32 g kg–1 year–1, respectively. Soil microbial C and N content were higher under CT than under NT. However, soil C:N ratios under NT were 17.4 and 9.7% higher than the CT, respectively, whereas soil microbial C:N ratios under NT were on average 9.47 and 9.70% higher. In addition, about 70% of CO2 net uptake and over 99% of net CH4 emissions occurred during the rice season in May–September in the rice–oilseed rape cropping system. Annual cumulative CH4 and daytime net ecosystem CO2 exchange (NEE) under NT was 1813.9 g CO2 equiv. m–2, 10.8% higher than that under CT. Our results suggest that a higher soil microbial C:N ratio and NEE (CH4 and daytime CO2) could contribute to increasing SOM/C in the surface soil under NT management.

Rice production in China has more than tripled in the past five decades mainly due to increased grain yield rather than increased planting area. This increase has come from the development of high-yielding varieties and improved crop management practices such as nitrogen fertilization and irrigation. However, yield stagnation of rice has been observed in the past ten years in China. As its population rises, China will need to produce about 20% more rice by 2030 in order to meet its domestic needs if rice consumption per capita stays at the current level. This is not an easy task because several trends and problems in the Chinese rice production system constrain the sustainable increase in total rice production. Key trends include a decline in arable land, increasing water scarcity, global climate change, labor shortages, and increasing consumer demand for high-quality rice (which often comes from low-yielding varieties). The major problems confronting rice production in China are narrow genetic background, overuse of fertilizers and pesticides, breakdown of irrigation infrastructure, oversimplified crop management, and a weak extension system. Despite these challenges, good research strategies can drive increased rice production in China. These include the development of new rice varieties with high yield potential, improvement of resistances to major diseases and insects, and to major abiotic stresses such as drought and heat, and the establishment of integrated crop management. We believe that a sustainable increase in rice production is achievable in China with the development of new technology through rice research.

Meeting the future food security challenge without further sacrificing environmental integrity requires transformative changes in managing the key biophysical determinants of increasing agronomic productivity and reducing the environmental footprint. Here, we focus on Chinese rice production and quantitatively address this concern by conducting 403 on-farm trials across diverse rice farming systems. Inherent soil productivity, management practices and rice farming type resulted in confounded and interactive effects on yield, yield gaps and greenhouse gas (GHG) emissions (N2O, CH4 and CO2-equivalent) with both trade-offs and compensating effects. Advances in nitrogen, water and crop management (Best Management Practices-BMPs) helped closing existing yield gaps and resulted in a substantial reduction in CO2-equivalent emission of rice farming despite a tradeoff of increase N2O emission. However, inherent soil properties limited rice yields to a larger extent than previously known. Cultivating inherently better soil also led to lower GHG intensity (GHG emissions per unit yield). Neither adopting BMPs only nor improving soils with low or moderate productivity alone can adequately address the challenge of substantially increasing rice production while reducing the environmental footprint. A combination of both represents the most efficient strategy to harness the combined-benefits of enhanced production and mitigating climate change. Extrapolating from our farm data, this strategy could increase rice production in China by 18%, which would meet the demand for direct human consumption of rice by 2030. It would also reduce fertilizer nitrogen consumption by 22% and decrease CO2-equivalent emissions during the rice growing period by 7% compared with current farming practice continues. Benefits vary by rice-based cropping systems. Single rice systems have the largest food provision benefits due to its wider yield gap and total cultivated area, whereas double-rice system (especially late rice) contributes primarily to reducing GHG emissions. The study therefore provides farm-based evidence for feasible, practical approaches towards achieving realistic food security and environmental quality targets at a national scale.

One of the technology options that can help farmers cope with water scarcity at the field level is alternate wetting and drying (AWD). Limited information is available on the varietal responses to nitrogen, AWD, and their interactions. Field experiments were conducted at the International Rice Research Institute (IRRI) farm in 2009 dry season (DS), 2009 wet season (WS), and 2010 DS to determine genotypic responses and water use efficiency of rice under two N rates and two water management treatments. Grain yield was not significantly different between AWD and continuous flooding (CF) across the three seasons. Interactive effects among variety, water management, and N rate were not significant. The high yield was attributed to the significantly higher grain weight, which in turn was due to slower grain filling and high leaf N at the later stage of grain filling of CF. AWD treatments accelerated the grain filling rate, shortened grain filling period, and enhanced whole plant senescence. Under normal dry-season conditions, such as 2010 DS, AWD reduced water input by 24.5% than CF; however, it decreased grain yield by 6.9% due to accelerated leaf senescence. The study indicates that proper water management greatly contributes to grain yield in the late stage of grain filling, and it is critical for safe AWD technology.

The aim of the study was to evaluate the variations in the rumen ecosystem at genus level and predicted functions of rumen bacteria by using whole crop corn silage (WCS), whole crop rice silage (WRS) or rice straw (RS) as forage sources in beef cattle ration. Ruminal digesta samples from 10 bulls per treatment were collected at day 60 of experimental period. The PCoA plots based on the Bray-Curtis distance matrix (BDM) expressed separation between WRS and WCS, WRS and RS using PC1 (P<0.05, 45.56%). The PCoA plots based on BDM also expressed separation among WRS, WCS and RS group using PC2 (P<0.05, 11.95%). Microbiota composition resutls at genus level showed that the most abundant genera were Prevotella (13.37%) and Ruminococcus (4.00%). Comparison of treatments represented that Prevotella, Treponema and Anaerostipes were higher in bulls fed WCS forage. Clostridium, Anaeroplasma and RFN20 were higher in bulls fed RS forage than animals fed WCS and WRS. Butyrivibrio was higher in WRS and RS treatments than WCS treatment group. Pseudobutyrivibrio was higher in bulls fed WRS forage than animals fed RS and WCS forage. Fibrobacter was higher in RS and WCS as compared to WRS. The results of functional alteration of rumen microbiota in different experimental groups represented that the leading modified function of the microbiome was the transporter. Based on findings of current study, it is concluded that microbial community at genus level in the rumen of bulls was highly altered by forage type. [ABSTRACT FROM AUTHOR]

CD4 T-cell depletion is a hallmark of HIV/AIDS, but the underlying mechanism is still unclear. We have recently shown that ataxia-telangiectasiamutated (ATM) deficiency in CD4 T cells accelerates DNA damage, telomere erosion, and cell apoptosis in HIV-infected individuals on antiretroviral therapy (ART). Whether these alterations in ART-treated HIV subjects occur in vitro in HIVinfected CD4 T cells remains unknown. In this study, we employed a cellular model of HIV infection to characterize the mechanisms underlying CD4 T-cell destruction by analyzing the telomeric DNA damage response (DDR) and cellular apoptosis in highly permissive SupT1 cells, followed by the validation of our observations in primary CD4 T cells with active or drug-suppressed HIV infection. Specifically, we established an in vitro HIV T-cell culture system with viral replication and raltegravir (RAL; an integrase inhibitor) suppression, mimicking active and ART-controlled HIV infection in vivo. We demonstrated that HIV-induced, telomeric DDR plays a pivotal role in triggering telomere erosion, premature T-cell aging, and CD4 T-cell apoptosis or depletion via dysregulation of the PI3K/ATM pathways. This in vitro model provides a new tool to investigate HIV pathogenesis, and our results shed new light on the molecular mechanisms of telomeric DDR and CD4 T-cell homeostasis during HIV infection. [ABSTRACT FROM AUTHOR]

Alagille syndrome (AGS) is a highly variable, autosomal dominant disease that affects multiple structures including the liver, heart, eyes, bones and face. Targeted region capture sequencing focuses on a panel of known pathogenic genes and provides a rapid, cost‑effective and accurate method for molecular diagnosis. In a Chinese family, this method was used on the proband and Sanger sequencing was applied to validate the candidate mutation. A de novo heterozygous mutation (c.3254_3255insT p.Leu1085PhefsX24) of the jagged 1 gene was identified as the potential disease‑causing gene mutation. In conclusion, the present study suggested that target region capture sequencing is an efficient, reliable and accurate approach for the clinical diagnosis of AGS. Furthermore, these results expand on the understanding of the pathogenesis of AGS. [ABSTRACT FROM AUTHOR]

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A series of studies were carried out in chamber room to investigate the injury mechanism under extreme temperature and at different grain filling stages with foliar application of plant growth regulators (Abscisic acid-ABA and salicylic acid-SA) on the rice cultivar Huanghuazhan. Grain filling rate and grain weight were measured as yield components, while seed germination rate, germination index and seed vigour index were measured as seed quality indices. Chlorophyll fluorescence parameters and active oxygen resistance activity were also analyzed. The results showed that the rate of grain filling and grain weight were significantly reduced under the extreme temperature conditions and at higher concentrations of the plant growth regulators. Superoxide dismutase (SOD) activity increased and decreased among treatments, while malondialdehyde (MDA) content was significantly high. Maximal photochemical efficiency of PS II (Fv/Fm) and the potential photochemical efficiency of PS II (Fv/Fo) also decreased under high temperature stress, whilst it increased and decreased under low temperature stress among treatments. [ABSTRACT FROM AUTHOR]

Excessive nitrogen (N) application to rice (Oryza sativa L.) crop in China causes environmental pollution, increases the cost of rice farming, reduces grain yield and contributes to global warming. Scientists from the International Rice Research Institute have collaborated with partners in China to improve rice N fertilization through site-specific N management (SSNM) in China since 1997. Field experiments and demonstration trials were conducted initially in Zhejiang province and gradually expanded to Guangdong, Hunan, Jiangsu, Hubei and Heilongjiang provinces. On average, SSNM reduced N fertilizer by 32% and increased grain yield by 5% compared with farmers' N practices. The yield increase was associated with the reduction in insect and disease damage and improved lodging resistance of rice crop under the optimal N inputs. The main reason for poor fertilizer N use efficiency of rice crop in China is that most rice farmers apply too much N fertilizer, especially at the early vegetative stage. We observed about 50% higher indigenous N supply capacity in irrigated rice fields in China than in other major rice-growing countries. Furthermore, yield response of rice crop to N fertilizer application is low in China, around 1.5 t ha-1 on average. However, these factors were not considered by rice researchers and extension technicians in determining the N fertilizer rate for recommendation to rice farmers in China. After a decade of research on SSNM in China and other Asian rice-growing countries, we believe SSNMis a matured technology for improving both fertilizer N use efficiency and grain yield of rice crop. Our challenges are to further simplify the procedure of SSNM and to convince policy-makers of the effectiveness of this technology in order to facilitate a wider adoption of SSNM among rice farmers in China. [ABSTRACT FROM AUTHOR]