To screen rice varieties suitable for the “rice-ratooning rice-rapeseed” planting model, 13 rice varieties including Renyou 6, Zhenzaoyou 939, and Jiyou 1127, etc. were used as materials (with Lingliangyou 268 as the control), and a selection experiment of regenerated rice varieties under the “rice-ratooning rice-rapeseed” model was conducted in Changsha (research area A) and Yiyang (research area B), Hunan Province, determine indicators such as reproductive period, yield, and yield composition. The results showed that, except for Shengliangyou 358, all other varieties had suitable growth periods for planting in the study area and could safely achieve full panicle. In research area A, the annual yields of Renyou 6 and Quanzaoyou 1606 were 14.00 and 14.27 t/hm², respectively, which increased by 5.34% and 7.37% compared to the control. In research area B, the annual yields of Renyou 6, Lingliangyou 741, and Quanzaoyou 1606 were 10.58, 10.56, and 10.76 t/hm², respectively, an increase of 7.65% to 9.68% compared to the control. The above varieties all mature before mid October and can safely transition the rapeseed crop. Overall, Renyou 6 and Quanzaoyou 1606 performed well in Changsha, Hunan Province, while Renyou 6, Lingliangyou 741, and Quanzaoyou 1606 performed well in Yiyang, Hunan Province. They are suitable for planting regenerated rice varieties in the cooperative “rice-ratooning rice-rapeseed” planting model, and can be selected according to local planting conditions in each region.

The large-scale planting performance of drought resistant rice variety Hanyou 73 was combined in Donghu Production Base, Dongqiao Town, Huian County, Xiamen, Fujian Province, its “rice+vegetable” water-dry rotation cultivation techniques and its advantages in arid land were summarized and analyzed. This variety was planted in a “rice+vegetable” rotation in the research area, with a total growth period of about 128 days and resistant to bacterial leaf blight and rice blast disease, with good drought resistance; the dry grain yield of rice was 7 542.75 kg/hm². Dryland cultivation techniques include land preparation, application of base fertilizer, and rotary tillage; after seed mixing or seedling cultivation, live broadcasting or waterless machine transplanting is carried out; arrange micro sprinkler irrigation pipe belts in the field according to the walking route of the rice transplanter wheels; after emergence, water the seedlings with water for greening, tillering, and heading filling to improve seedling quality and rice seed setting rate; according to the seedling situation in the field, apply tillering fertilizer, jointing fertilizer, and heading fertilizer to cultivate strong seedlings; dryland has more grass damage than paddy fields, and generally adopts measures such as closed weeding as the main method, chemical pesticides as auxiliary, and manual removal and remediation for prevention and control; according to local pest and disease monitoring information, timely prevention and control of diseases and pests such as sheath blight and rice planthopper. The application of the “rice+vegetable” water-dry rotation model and dryland waterless machine transplanting technology has technical management advantages such as saving labor and reducing consumption, facilitating water control, and improving fertilizer utilization efficiency; and social benefits such as improving farmland utilization efficiency, conserving water resources, and improving soil environment. This article provides a reference for the promotion and application of the “rice+vegetable” water-dry rotation model in relevant region’ dry land.

The types of rice pests and diseases, as well as their occurrence rules in Huazhou City, Guangdong Province, were investigated in this study, to provide a basis for prediction, forecasting, and green control measures. Based on multi-year survey data and historical records, the species of rice pests and diseases in Huazhou from 1980 to 2023 were investigated, and the occurrence and epidemic patterns of major pests and diseases, and their causes were analyzed. It was revealed that a total of 55 types of rice pests and diseases were present in the region, comprising 21 diseases and 34 pests. Among the diseases, fungal diseases were found to be the most prevalent, with 12 types accounting for 57.1% of the total. Leaf-eating and sap-sucking pests were identified as the most common among the pests, with 12 types each, both accounting for 35.3% of the total. A preliminary exploration was conducted into the regularty of epidemic of major rice pests and diseases in the region over the years, revealing differences in the severity of pests and diseases damage across different decades. In the 1980s, severe damage was caused by pests such as Tryporyza incertulas, Nilaparvata lugens, Thrips oryzae, Orseoia oryzae and diseases such as rice blast, bacterial leaf blight, sheath blight, false smut, and rice gall dwarf disease, while other pests and diseases were relatively mild. From the 1990s onwards, an increase in severity was observed for Nilaparvata lugens, Cnaphalocrocis medinalis, sheath blight, bacterial leaf streak, and rice orange leaf disease. In the 2020s, Sesamia inferens, Chilo suppressalis, bacterial leaf streak, sheath blight, bacterial leaf blight, and southern rice black-streaked dwarf virus were found to have become more prevalent. It was concluded through a comprehensive analysis that the occurrence and evolution of these rice pests and diseases were mainly driven by a combination of three factors: the host plant (crop resistance), pathogenic organisms (or initial pest sources), and environmental conditions (including meteorological conditions, cultivation practices, and farming systems). It was also noted that different pests and diseases had their own specific factors contributing to their evolution. A reference was provided by this study for improving the management of rice pests and diseases in the region and for promoting the sustainable development of agriculture.

The lodging resistance of rice is a complex character, and the analysis of its genetic effect is valuable for improving the lodging resistance of rice. The genetic patterns and parameters of 16 lodging resistance traits in indica and japonica crossbred progeny were analyzed by using additive and dominant genetic model of plant quantitative traits. The variation of additive variance in the ratio of main effect of 9 traits ranged from 49.9% to 72.1%. The dominant variance in the ratio of dominant effect of 7 traits ranged from 48.2% to 87.1%. The additive and dominant variances of 9 traits accounted for significant or extremely significant phenotypic variances, which were controlled by both additive and dominant effects of genes. The 8 characters, such as basal folding resistance and sheath leaf thickness, were negatively correlated with lodging index, which was conducive to improving basal folding resistance and toppling resistance of rice. Indica japonica intermediate type parents have strong lodging resistance heterosis and high breeding value. Effective use of the genetic characteristics of each character has important guiding significance for breeding lodging resistant indica and japonica hybrid generation.

To understand the current status of Cd contamination and regulation in rice, this review comprehensively summarizes the following aspects: the absorption and translocation patterns of Cd in rice, Cd accumulation characteristics in different rice varieties and plant organs, the impacts of Cd on rice yield and quality, the effects on seed germination, as well as the influences on rice growth and physio-biochemical processes. Additionally, mitigation strategies for reducing Cd accumulation are systematically discussed. Based on China's current situation of rice Cd contamination, future research directions are proposed: (1) developing novel in-situ passivation materials, such as nano-adsorbent materials, which should have the characteristics of eco-friendly, cost-effective, high-efficiency, and user-friendly features; (2) creating more scientifically sound soil remediation technologies that can efficiently remove various heavy metals without damaging soil structure and ecological balance; (3) employing novel molecular breeding techniques to cultivate Cd-tolerant and stable ultra-low Cd-accumulating rice varieties, along with developing corresponding cultivation practices. This study aims to provide valuable references for Cd contamination control.

In order to explore the pollution status and health risks of heavy metals in rice grains in a county of southern Henan, 68 rice grain samples were collected in the area in September 2021. The contents of chromium, arsenic, cadmium, lead, and mercury were determined by inductively coupled plasma mass spectrometry (ICP-MS-TQ) and direct mercury detection. The risk degree of heavy metals in rice was evaluated by single factor and Nemerowcomprehensive pollution index method, and the potential health risk of heavy metals from rice grains was evaluated by target hazard quotient (THQ) promoted by US EPA. The results showed that the average content of heavy metals in 68 rice grains did not exceed the Chinese Food Hygiene Standards, but the arsenic and cadmium contents in some samples exceeded the standards. The comprehensive pollution index (P_N) of heavy metals in rice grain was 0.49, which was safe. ADD of adults and children was higher than RfD, and hazard quotients (HQ) of As were 3.11 and 4.80, which indicated that there was a certain risk of arsenic content in rice grains. The total hazard index (HI) of heavy metals to the exposed population was greater than 1, indicating that the long-term consumption of the rice by local residents may cause adverse health effects. In summary, the rice grain samples in the research area have been contaminated with arsenic, posing certain health risks. The local government needs to strengthen dynamic monitoring of the rice planting process, pay attention to the changes in the form and effective state of arsenic, ensuring food security.

The characteristics, suitable planting areas, cultivation techniques, and high-yield seed production techniques of Quanxiangyou 89 were summarized and analyzed based on its production practice. This variety is planted in the upper, middle, and lower reaches of the Yangtze River and exhibits characteristics such as suitable growth period, excellent rice quality, and high-yield; it is suitable for planting in areas with low incidence of rice blast disease, such as Pingba hilly rice growing areas in Sichuan Province and mid to low altitude indica rice growing areas in Yunnan Province. The high-yield cultivation techniques include early sowing in time and cultivating multi-tiller seedling; heavy application of bottom fertilizer, timely topdressing; dry and wet alternate pipe water and timely pest control. High-yield seed production techniques include post tobacco seed production in areas with an altitude of 250-500 meters; according to the different seed production seasons, ensure that the parental sowing difference period is between 6.5 and 7.5 leaves; soaking seeds with pesticides, spraying paclobutrazol, etc., to promote the health, dwarfism, and multiple tillering of seedlings; arranging a parent to parent ratio of 1∶8; managing fertilizer and water according to the growth of seedlings in the field; timely prevention and control of diseases and pests such as neck blight and rice planthopper based on actual field investigations and local pest and disease reports; adopting the method of young ear peeling to predict flowering period, it is advisable to use the same period as the parents in the early stage of young ear differentiation; spraying gibberellin when the panicle reaches 15%; pay attention to removing impurities and maintaining purity throughout the entire seed production process; harvesting begins when 75% of the seeds are ripe and dried promptly after harvesting. This article provides references for the demonstration and promotion of high-yield seed production techniques for Quanxiangyou 89.

Based on the rice production practice in the Southern Jiangsu Province, the high-quality and high-yield cultivation techniques of rice and their promotion strategies were summarized and analyzed. High-quality and high-yield cultivation techniques include selecting varieties with high-quality, high-yield, strong resistance, and wide adaptability according to local conditions; making preparations for seedling field configuration, nutrient soil (substrate) preparation, seed treatment, and scientific sowing; water management, fertilization management, and pest control of seedbeds; adjusting the planting distance and seedling amount of transplanting machinery according to the variety type to achieve precise cultivation; field management needs to strengthen the supporting ditch system to reduce drainage and waterlogging, timely and appropriately fertilize according to the growth process and seedling growth of rice, and adopt comprehensive control measures of ecological regulation and scientific medication for the prevention and control of diseases and pests such as sheath blight, rice blast disease, rice planthopper, and stem borer; timely use machinery for harvesting, and pay attention to moisture and mold prevention during storage. Corresponding promotion strategy includes strengthening publicity and guidance, providing financial support, etc., to motivate planting subjects; keeping up with the trend of technological development, improving technical points, and implementing key technologies; constructing high-yield demonstration area, demonstrating the application of high-yield and high-efficiency cultivation techniques; carrying out on-site observation, technical lectures, and skill competitions to strengthen technical training. This article provides a reference for the promotion and application of high-quality and high-yield rice cultivation techniques in related rice growing areas such us Southern Jiangsu Province.

To investigate the absorption and utilization of fertilization between single season rice fields under different fertilization methods, Guanliangyouhuazhan was used as the material, 9 different fertilization treatments were set up (PK, conventional fertilization nitrogen free zone; NK, conventional fertilization in phosphate free areas; NP, conventional fertilization in potassium free areas; NPK, conventional fertilization in the entire application area; PK1, deep lateral fertilization in nitrogen free areas; NK1, deep lateral fertilization in phosphate free areas; NP1, deep lateral fertilization in potassium free areas; NPK1, deep lateral fertilization in the entire application area; blank area, no fertilization), to determine the effects of each treatment on rice agronomic traits, yield, and fertilizer utilization efficiency. The results showed that under the same fertilizer type and quantity conditions, the ear length, total number of grains per ear, and seed setting rate in the mechanical side deep fertilization area were higher than those in the conventional fertilization area. The NPK1 treatment had the highest plant height, ear length, total number of grains per ear, and seed setting rate. Compared with conventional fertilization, mechanical side deep fertilization had increased grain yield at the same fertilization level; the highest grain and stem leaf yield was achieved with NPK1 treatment. The utilization rates of nitrogen, phosphorus, and potassium fertilizers in conventional fertilization were 36.95%, 31.07%, and 42.50%, respectively, while the utilization rates of nitrogen, phosphorus, and potassium fertilizers in mechanical side deep fertilization were 45.18%, 38.59%, and 49.99%, respectively. Overall, the application of mechanical side deep measurement for nitrogen, phosphorus, and potassium fertilizer application can achieve higher rice yields and higher fertilizer utilization efficiency.

【Objective】Rice grain size is a quantitative trait controlled by multiple genes. They can be dissected into a single segment substitution line (SSSL), which is of great significance for their genetic mechanism study and breeding by design. 【Method】Z492, a chromosome segment substitution line in the genetic background of Nipponbare, was used as material to dissect QTL for rice grain size by mixed linear model (MLM) method. 【Result】The F₂ population was constructed from Nipponbare/Z492 to identify four QTL for grain size, including qGL6 and qGL7 for grain length and qRLW7 and qRLW12 for rate of grain length to width. Then three single-segment substitution lines (SSSL, S1-S3) and 3 dual-segment substitution lines (DSSL, D1-D3) carrying these QTL were further constructed. And the SSSL were then used to detect eight QTL for grain size, including qGL6, qGL7 and six newly identified QTL (qGW6, qRLW6, qGW7, qGWT7, qGL12, qGW12). Simultaneously, the genetic model of different QTL in 3 DSSL were analyzed. The results showed that interaction of qGL6 (a=0.26 mm) and qGL7 (a=0.21 mm) produced -0.21 mm of grain length epistatic effect, which resulted in the genetic effect (0.26 mm) of D1 equal to the additive effect of each QTL. Thus, the grain length (7.98 mm) of D1 displayed no difference from those (7.89 and 7.98 mm) of S2 with qGL7 and S1 containing qGL6, while significantly longer than that (7.47 mm) of Nipponbare. The result indicated that it is not necessary to pyramid qGL6 and qGL7 in breeding by design for increasing grain length. qGW6 (a=0.07 mm) and qGW12 (a=0.06 mm) belonged to independent inheritance in D2, thus, the genetic effect (0.13 mm) after pyramiding of qGW6 and qGW12 caused the grain width (3.65 mm) of D2 broader significantly than any of the SSSL with the single QTL. So, qGW6 and qGW12 can be selected to increase grain width in breeding by design. Interaction of qGW7 (a=0.11 mm) and qGW12 (a=0.06 mm) yielded -0.10 mm of epistatic effect, causing the grain width genetic effect (0.07 mm) of D3 parallel to the additive effect of qGW12. Thus, the grain width (3.59 mm) of D3 exhibited no difference with that (3.56 mm) of S3 carrying qGW12, while wider significantly than that (3.44 mm) of Nipponbare and narrower significantly than that (3.66 mm) of S2. 【Conclusion】It is very necessary for breeding by design to identify QTL for different important traits using SSSL and DSSL. Pyramiding different QTL produce various genetic models. Some display independent inheritance, and others exhibit various epistatic effects. In addition, to cross with S1 and S3 can realize the goal of longer, wider and heavier rice grain, and to cross with S1 and S2 can reach the target of heavier grain weight, while to cross with S2 and S3 have no any effects in grain size.

The yield and agronomic traits of rice are affected by the cultivation environment and their adaptability, and the varieties with wide adaptability are less affected by the cultivation environment. This study aims to clarify the adaptability of ‘Yunjing 37’, a new japonica rice variety with good eating quality. The stability of yield and agronomic traits of ‘Yunjing 37’ and control varieties were analyzed by AMMI model, which planted in 6 sites in Yunnan Province for two consecutive years. All traits showed highly significant differences between varieties and environment, along with significant interaction effects between varieties and environment. Based on the stability parameters ASV, Di, WAASBi, the grain number, seed setting, 1000-weight, plant height, length and angle of the flag leaf, which were closely related to yield and plant type, ‘Yunjing 37’ showed the best stability among the four varieties. This indicates that different environmental conditions have relatively little influence on the yield and plant type of ‘Yunjing 37’. Therefore, ‘Yunjing 37’ has wide adaptability and is suitable for widespread application in Yunnan japonica rice area.

To study the environmental pollution of paddy fields in a region of Sichuan, this paper focused on paddy soil and rice as the main research objects. A total of 216 soil and rice samples were collected from the area, and the heavy metal pollutants in soil and rice in the study area were evaluated by testing the content of eight heavy metal elements, namely arsenic, lead, cadmium, chromium, mercury, copper, zinc and nickel in soil, and the content of five heavy metals, namely arsenic, lead, cadmium, chromium, and mercury in rice, using the single-factor pollutant index method and the Nemero composite pollutant index method, as well as performing the quantitative analysis of the association between various heavy metal elements in soil and rice. The results showed that: (1) the average content of cadmium and mercury in the soil of this study area was 0.47 and 0.98 mg/kg, respectively, which exceeded the standard, and their exceedance rates were 27.78% and 34.26%, respectively. The combined pollution index of Nemero in this study area was 1.11 mg/kg and the pollution level was mild. (2) There were significant correlations between the eight elements in the soil and the pathways of heavy metal accumulation might be the same. The coefficient of variation of soil Hg was 163.20%, which was highly variable, indicating that local pollution sources had a strong influence on heavy metals in soil, and the exceeding of Hg content in soil was mainly anthropogenic. (3) Cadmium, chromium and lead in rice had exceeded the standards, with exceedance rates of 19.44%, 3.70% and 19.44%, respectively. The study shows that the degree of heavy metal enrichment in rice has some correlation with soil heavy metal content and is related to the chemical form of heavy metals. It has certain guiding significance for food safety and heavy metal pollution remediation and treatment.

The study subjected 20 Ting’s rice varieties, including P0340, CII141, and R289 were treated with high temperature stress during seed germination，normal culture was used as control, 10 key germination indexes such as germination potential, germination rate, and root and shoot length were measured. By using the membership function comprehensive evaluation method and grading evaluation value, the heat resistance comprehensive evaluation was carried out. Meanwhile, correlation analysis, regression analysis and cluster analysis were carried out, combined with the determination of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) and the activity analysis of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), the differences of growth indexes and physiological indexes of different rice varieties at germination stage were discussed, so as to screen rice varieties with strong heat resistance.The results showed that after high temperature treatment, the growth indexes such as germination potential of rice were different between varieties and treatments.In terms of heat resistance comprehensive evaluation, P0340 ranked first, showcasing strong heat tolerance, while Y595 ranked last, indicating weak heat tolerance. Correlation analysis and regression analysis established that germination rate and seedling dry weight could be used as important indexes for heat resistance identification.According to the cluster analysis, the heat resistance of the rice varieties tested was divided into 5 categories:extremely strong, strong, medium, weak and extremely weak. Among them, the variety with strong heat resistance was P0340, the varieties with strong heat resistance were CII141, R289, and Y1544, 10 varieties with medium heat resistance included R107 and Δ133, etc., and 5 varieties with weak heat resistance included PII140 and PII21,etc. The very weak heat resistance variety was Y595. In terms of physiological indexes, compared with control, under high temperature stress, H₂O₂ and MDA contents of P0340 increased less, the difference was not statistically significant (P>0.05). The activities of SOD, CAT, and POD in P0340 significantly increased compared to the control (P<0.05). These findings suggest that P0340 displays strong heat tolerance during the germination stage, characterized by minimal accumulation of reactive oxygen species and enhanced antioxidant capacity. In conclusion, the identification of the high heat tolerance rice variety P0340 in this study offers a valuable genetic resource for the development of new heat tolerance varieties.

To investigate the effect of spraying foliar silicon fertilizer application on the lodging resistance of rice stems, Ningjing 8 was selected as the material for field experiments, and 3 concentrations of foliar silicon fertilizer were set up, including 0 (CK), 100 and 200 mg/L. The mechanical indexes of lodging resistance, such as breaking moment M, internode configuration, and internode fullness, such as stem thickness, wall thickness and internode length, were measured. The results showed that compared with CK, the fracture moment M, section modulus Z, and bending stress BS of rice stem were increased by spraying 200 mg/L silicon fertilizer on the leaf surface. The stem diameter, inner and outer diameters of main and short axes of rice were increased. There was no significant effect on plant height, but the length between the first, second, and third segments of the base was significantly reduced. It had little effect on basal internode fullness. In conclusion, reasonable spraying of foliar silicon fertilizer can improve the mechanical strength of rice stems and the lodging resistance by increasing the stem diameter, the inner and outer diameter of the main and short axes of rice, while reducing the length between the first, second, and third nodes of the base. The effect of 200 mg/L foliar silicon fertilizer treatment is better.

Y Liangyou 919 is an indica two-line hybrid rice variety selected from Y58S as the female parent and R919 as the male parent，the characteristics of its parents and high-yield seed production techniques were introduced. Y58S is a widely adaptable rice photoperiod temperature sensitive sterile line with excellent compatibility and high breeding yield; R919 is a dominant recovery line with lodging resistance, disease resistance and strong coordination force. Y Liangyou 919 can be used for post tobacco seed production in areas with an altitude of 300-500 meters in Northwest Fujian Province. The high-yield seed production techniques includes reasonable arrangement of the sowing time difference between the father and mother plants, with the father plant sowing in mid May and the mother plant sowing in mid June being suitable; choose fields that are windward and sunny, have convenient drainage and irrigation, and have a medium to high fertility level as seedling fields. Use appropriate sowing rates, soak seeds with disinfectants, apply sufficient base fertilizer, and timely and appropriate topdressing. Scientifically manage water and prevent diseases, pests, and weeds in a timely manner to cultivate strong seedlings; after harvesting tobacco leaves, timely plow and weed the fields, and transplant them, with a parent to child ratio of 1∶8; the full fertility period of the field, shallow water transplanting, inch water greening, thin water tillering, sufficient sun drying of seedlings, inch water booting, and dry and wet strong seeds should be achieved; apply sufficient basal fertilizer and apply appropriate topdressing according to the growth of the seedlings; timely prevention and control of diseases and pests such as rice sheath blight, rice leaf roller, and neck blight based on the actual situation in the field and local pest and disease monitoring; the ideal flowering period for seed production of this variety should meet the standard that the male parent’s initial flowering period is 2 days later than the female parent’s, and should be adjusted in a timely manner according to the actual situation in the field; when the number of spikes reaches 25% to 30%, spray “920” plant growth regulator to ensure uniformity and pollination, and improve the fruiting rate; timely remove impurities and maintain purity, eliminate premature and abnormal plants; after the flowering is completed, promptly cut off the male parent and harvest 90% of the seeds in the field when they are ripe. This article provides references for high-yield seed production and promotion planting of hybrid rice.

The distribution of pests during rice cultivation is characterized by small scale and high density, making identification challenging. This article was based on deep learning and the classic YOLOv8s lightweight model was used to train and recognize 14 types of rice pests, including rice leaf roller, rice leaf caterpillar, and rice stem maggot, etc. The model training and verification results were obtained. The training results showed that the model has good convergence speed and stability; the verification results indicated that the model has good performance, with the recognition accuracy of 0.788, the recall rate of 0.721, and the recognition accuracy of 0.809, mAP@0.5 of 0.772 for 14 rice pests. Overall, the model had good performance and can meet the requirements of rice pest detection. The research results provide references for the identification of rice pest.

To understand the research progress of colored rice and its related genes, the functions of colored rice were summarized, and the effects of Ra, Rc, Rd, OsC1 and OsB2 genes on the traits of colored rice were analyzed. These genes determine the red, black, and purple colors of rice grains by influencing the accumulation of anthocyanins and proanthocyanidins. In this paper, we point out the limitations of related rice color genes in rice breeding. And the current research is not systematic enough to make full use of the diversity of these genes and prove the role of these genes in other rice traits. It is believed that genome-wide association analysis and population genetics method can be used to systematically analyze the variation and expression patterns of these genes in different rice varieties, and provide data support for rice genetic improvement. We can also use genetic methods and modern biotechnology methods to explore the functions of these genes in other traits of rice, to provide theoretical basis for the improvement of multiple traits of rice.

The microbial composition and function in the rhizosphere is the research focus of microbial ecology. Analysis of the diversity of soil microbial communities in the root system of paddy rice and the effects of environmental factors on soil microorganisms can provide reference value for the sustainability of soils in the growing areas of paddy rice and the conservation of land resources. In this study, we used 16S rRNA high-throughput sequencing technology to determine the bacterial composition of soil microorganisms in the rhizosphere of paddy rice, and analyze the composition and diversity of microbial communities sampled from different regions, and explore the relationship between soil microbial diversity and soil physicochemical properties. The results showed that a total of 33862 OTUs, belonging to 38 phylums, 88 orders, 214 orders, 514 families and 2268 genera, were obtained from the paddy rice rhizosphere soil samples collected from the four regions by sequencing. At the phylum level, the dominant phyla of paddy rice rhizosphere soil bacteria collected from the four regions were Proteobacteria, Bacteroidetes and Firmicutes. At the genus level, Limisphaera was the dominant taxon of paddy rice rhizosphere soil bacteria. As shown by the Alpha diversity index, the species diversity and richness of paddy rice inter-root soil bacteria collected from the four regions were generally as followed: 68^th Regiment of the Corps (D)> Dairy Farm of Yili Prefecture (A)> Chabchal Town (B)> Sundzach Niuzhu Township (C); the Beta diversity index indicated that the paddy rice rhizosphere soil collected from the four regions differed accordingly in their bacterial community compositions, with greater differences existed between group A and other groups. The correlation analysis between soil bacteria and environmental factors concluded that the main influencing factors on the composition of microbial bacterial communities in paddy rice rhizosphere soils might be nitrogen, total potassium, and organic carbon. This study clarified the rhizosphere soil conditions and rhizosphere soil bacterial community characteristics of paddy rice distributed in the Ili River Valley, and provided theoretical support for the study of soil ecosystems in the Ili River Valley.

Rice is the world’s largest food crop, but it often encounters flowering asynchronization problems during hybrid rice seed production.  In addition, the slow closure of female florets leads to seed mildew and affects the quality.  The hormone abscisic acid (ABA) plays a crucial role in plant responses to abiotic stresses.  Previous studies showed that exogenous ABA promotes floret closure, although the molecular mechanisms and effects of endogenous ABA on floret closure remain unknown.  In this study, the effect of endogenous ABA on floret closure and the molecular mechanism by which ABA promotes floret closure through sugar transporters were investigated by changing the expression levels of OsNCED3 and OsPYL1 in rice.  The results showed that overexpression (OE)-OsNCED3 increased the endogenous ABA level of florets.  Florets closed 5.91 min earlier and OsNCED3 gene knockout line delayed the closure of florets by 5.08 min compared with the wild type.  In addition, OsPYL1 regulated the endogenous ABA content and changed the sensitivity to ABA such that the floret closure times for OE and CRISPR-Cas9 (CR) were 9.84 min earlier and 12.78 min later, respectively, resulting in an increase in the split husk rate to 15.4%.  The gene expression levels of some sugar transporters (STs) changed.  The OsPYL1 and OsSWEET4 proteins could interact on the cell membrane.  These results indicate that ABA promotes the closure of rice florets and the enhanced sensitivity to ABA promotes this effect even more.  The molecular mechanism is mainly related to downstream sugar transporters that respond to the ABA signaling pathway, especially OsSWEET4. 

The aim was to explore the growth and development characteristics of ‘Si te’ late indica rice and provide theoretical support for its promotion and application. Many years field tests were conducted, with the typical ‘Si te’ late indica rice variety ‘Xiyou 447’ and the main rice variety ‘Jinyou 207’ in the middle and lower reaches of Yangtze River as experimental materials. Yield and growth characteristics were measured and breeding progress of ‘Si te’ late indica rice was summarized. Whole growth period of ‘Xiyou 447’ was 3-5 days shorter than that of ‘Jinyou 207’, and yield was increased by 7.5%-19.4%. Yield advantage of ‘Xiyou 447’ was mainly due to its synergistic improvement of dry matter accumulation and harvest index, as well as the higher total grain number per spike. The initial and terminal time of fast accumulation period of dry matter, nitrogen, phosphorus and potassium of ‘Xiyou 447’ were later than ‘Jinyou 207’, and mean accumulation speed was higher than ‘Jinyou 207’. Methane emission flux of ‘Xiyou 447’ was higher than ‘Jinyou 207’ at vegetative growth stage, but lower than ‘Jinyou 207’at heading and filling stage. In addition, ‘Xiyou 447’ had higher lodging resistance, which was mainly due to its lower plant height, shorter basal internode and higher stem wall thickness. ‘Si te’ late indica rice has short growth period, high yield, low methane emission and strong lodging resistance, so it has a good prospect for promotion and application.

This study aims to investigate the effects of Kocuria rosea SDB9 and Brevibacterium frigoritolerans SDB5 on the nutritional quality of rice. Using rice as the experimental material, the seeds were soaked with SDB9, SDB5, and a 1:1 mixture of both strains. The content of nine nutritional components in the rice grains was measured after harvest. The results were as follows. Compared to the control group (CK), the starch content in the experimental groups increased by only 1%, which was not statistically significant; crude protein content decreased by 3%-5%, also was not significant; crude fat content increased in all treatments, with a significant increase of 14.9% in the SDB9+5 treatment; soluble total sugar content decreased by 52.5%-58.3%, which was highly significant; reducing sugar content increased in all treatments except for a slight decrease of 0.6% in the SDB5 treatment, with a significant increase of 25.9% in the SDB9 treatment and an 8% increase in the SDB9+5 treatment, which was not significant; soluble protein content decreased in all treatments, with a significant decrease of 14.9% in the SDB9+5 treatment; cellulose content increased by 0.8%-0.9% in all treatments except for a slight decrease of 0.2% in the SDB9+5 treatment; vitamin C content decreased in all treatments, with a highly significant decrease of 64.5% in the SDB9 treatment and a significant decrease of 16.1% in the SDB5 treatment, while the SDB9+5 treatment showed a significant decrease of 35.5%; nitrate content decreased by 1%-12.8%, with no significant differences observed. In summary, treatment with SDB9 and SDB5 alone or in combination resulted in a slight increase in starch content and an approximate 8% decrease in crude protein content, improving rice palatability. The increase in crude fat and decrease in nitrate levels contributed positively to quality improvement. This indicates that Kocuria rosea SDB9 and Brevibacterium frigoritolerans SDB5 can improve the nutritional quality of rice to some extent. The evaluation of these two strains based on nutritional quality ranked them as follows: SDB9 > SDB9+5 > SDB5 > CK.

To analyze the effects of organic substitution of partial fertilizers on soil properties and rice growth under different fertility levels, a experiment for rice to replace chemical fertilizers with 15% organic fertilizer with low, medium, and high fertility levels was conducted. Nutrients such as organic matter and alkaline nitrogen, as well as indicators such as 1 000-grain weight, tiller number, and plant height of rice were measured to analyze nutrient absorption and fertilizer input and output. The results showed that, in terms of soil nutrient, compared with conventional fertilization, 15% organic fertilizer substitution increased the effective phosphorus content by 24.22% in medium fertility plots, significantly increased the available potassium content by 27.71% in high fertility plots; yield aspect, 1 000-grain weight and yield of rice increased by 0.60, 0.51, and 0.94 g and 29, 143, and 55 kg/hm², respectively, in plots with low, mediom and high fertility levels; nutrient utilization aspect, the total potassium content of rice straw increased by 78.08%, 28.85%, and 29.44% compared with conventional fertilization on plots with 3 fertility levels, respectively; economic benefits aspect, 15% organic fertilizer substitution saved fertilizer costs by 187.4 yuan/hm², and the average output value increased by 196.7 yuan/hm². In summary, the use of 15% organic fertilizer instead of chemical fertilizers could be beneficial for increasing soil nutrients and rice yield in low, medium, and high fertility plots. The research provides references for reducing fertilizer usage and promoting green rice production.

To explore and utilize the precious red rice germplasm resources in China, nutritional value and processing application of red rice were discussed, and relevant situation of 3 independent innovative germplasm (varieties) of red rice was introduced in combination with the germplasm innovation work of our team for many years, and the research direction of red rice was put forward. The results show that red rice contains the same basic nutrients as milled rice, and the types and contents of bioactive substances are higher than milled rice, which can be widely used in food and health products. After many years of independent innovation, our team selected and bred three lines of red rice sterile line ‘Gangte A’, with brown rice rate of 77.6%, head yield of 67.4%, chalkiness of 27.6%, amylose content of 12.4%. Yield of the three-line hybrid rice ‘Gangteyou 8024’ was 9581.6 kg/hm², with brown rice rate of 78.7%, head yield of 60.3%, chalkiness of 7.8%, amylose content of 15.1%. Yield of the two-line hybrid rice ‘E liangyou 32’ was 7307.6 kg/hm², with brown rice rate of 78.9%, head yield of 62.8%, chalkiness of 6.3%, amylose content of 13.3%. In view of the prominent problems of low sales volume and few kinds of red rice and its products in the Chinese market, four research directions of red rice were put forward, including strengthening the research and utilization of existing red rice germplasm resources, breeding new varieties of red rice with high yield and disease resistance, carrying out research on supporting cultivation technology and carrying out research on processing technology. Red rice is a kind of special rice resources with red seed coat due to pigmentation, which has both therapeutic and medicinal value, and has huge market potential. This paper can provide reference for the promotion and application of red rice in production.

The study aims to improve the automatic recognition of rice pest and disease images and better guide agricultural pest and disease control. Using a combination of transfer learning and ResNet-18 model, we organized open source plant disease data on the internet, and obtained images of 9 rice pests and diseases, including bacterial blight, blast and Tungro, as well as a healthy leaf as the research objects. 11414 cleaned images were selected to establish a dataset for model training, and the 30% dataset was split as the test set. On the basis of six pre trained models such as ResNet-18, GoogLeNet, VGG-16, and MobileNet-v2, a series of parameter adjustments were made to the transfer model. The results show that: (1) under the consistent training parameters, the proposed model ResNet-18 has significantly higher validation accuracy and lowest loss value compared with MobileNet-v2, AxeNet, VGG-16, GoogLeNet, SqueezeNet, and the original ResNet-18 model. The final accuracy of the model is 96.97%. (2) Compared with the original model, the training accuracy of all transferred learning models has been improved significantly, with the improved accuracy ranging from 5.03% to 13.90%. The optimized training model has the characteristics of fast recognition speed and improved accuracy, which can accurately and quickly identify the type of crop disease, providing support for the automatic diagnosis of crop diseases.

The high labor demand during rice seedling cultivation and transplantation poses a significant challenge in advancing machine-transplanted rice cultivation.  This problem may be solved by increasing the seeding rate during seedling production while reducing the number of seedling trays.  This study conducted field experiments from 2021 to 2022, using transplanting seedling ages of 10 and 15 days to explore the effects of 250, 300, and 350 g/tray on the seedling quality, mechanical transplantation quality, yields, and economic benefits of rice.  The commonly used combination of 150 g/tray with a 20-day seedling age in rice production was used as CK.  The cultivation of seedlings under a high seeding rate and short seedling age significantly affected seedling characteristics, but there was no significant difference in seedling vitality compared to CK.  The minimum number of rice trays used in the experiment was observed in the treatment of 350–10 (300 g/tray and 10-day seedling age), only 152–155 trays ha–1, resulting in a 62% reduction in the number of trays needed.  By increasing the seeding rate of rice, missed holes during mechanical transplantation decreased by 2.8 to 4%.  The treatment of 300–15 (300 g/tray and 15-day seedling age) achieved the highest yields and economic gains.  These results indicated that using crop straw boards can reduce the application of seedling trays.  On that basis, rice yields can be increased by raising the seeding rate and shortening the seedling age of rice without compromising seedling quality.

This study investigated the use of raspberry extract (RBE) for mitigating ethyl carbamate (EC) accumulation in Chinese rice wine (Huangjiu), a traditional fermented beverage.  It focused on the addition of RBE to the fermentation mash and its effects on EC levels.  The results showed a significant reduction in EC production that could be attributed to RBE’s role in altering urea and citrulline catabolism and inhibiting arginine metabolism, thus preventing EC precursors from reacting with ethanol.  Additionally, RBE enhanced the rice wine’s flavor profile, as shown by volatile component and amino acid analysis.  This study also explored RBE’s impact on the metabolism of arginine by Saccharomyces cerevisiae in a simulated fermentation environment, and found increased arginine, reduced urea and citrulline levels, altered enzyme activities, and gene expression changes in the arginine metabolism and transport pathways.  In conclusion, the results clearly demonstrated RBE’s efficacy in reducing the EC content in Chinese rice wine, offering valuable insights for EC reduction strategies.

Seed shattering is a major factor limiting rice production, and breeding new rice varieties with moderate seed shattering is a key challenge faced by rice breeders worldwide. Rice is the most important cereal crop in China, plays a vital role for national food security. Seed shattering is one of the most important traits during rice domestication, and the abscission zone is the important region to control seed shattering. Compared with wild rice, cultivar has eliminated the seed shattering with partially developed abscission layer. Seed shattering not only has a direct impact on the yield, but also affects the way of its mechanical harvest. In order to breed rice varieties with moderate seed shattering in agricultural production, it is necessary to mine and utilize important seed shattering genes and introduce them into excellent rice varieties for genetic improvement, so as to breed new rice varieties suitable for mechanical harvesting with moderate seed shattering. Several seed shattering genes had been identified by map-based cloning, such as SH4/SHA1, qSH1, OsSh1/ObSH3, and their functional mechanisms had been analyzed. At the same time, new rice materials with moderate seed shattering have been successfully developed through CRISPR/Cas9 gene editing technology, gamma ray mutagenesis technology and gene introduction methods. Seed shattering has an important effect on grain yield and rice harvesting methods, in this paper, we reviewed the methods, physiologic basis, the identification of seed shattering genes and genetic mechanism of seed shattering in rice. At the same time, it is proposed that by using the important genes in excellent rice germplasm resources, could provide reference for exploring the mechanism of rice seed shattering, and breed new rice varieties suitable for mechanical harvesting with moderate seed shattering.

Seed aging tolerance during storage is generally an important trait for crop production, yet the role of small auxin-up RNA genes in conferring seed aging tolerance is largely unknown in rice.  In this study, one small auxin-up RNA gene, OsSAUR33, was found to be involved in the regulation of seed aging tolerance in rice.  The expression of OsSAUR33 was significantly induced in aged seeds compared with unaged seeds during the seed germination phase.  Accordingly, the disruption of OsSAUR33 significantly reduced seed vigor compared to the wild type (WT) in response to natural storage or artificial aging treatments.  The rice OsSAUR33 gene promotes the vigor of aged seeds by enhancing their reactive oxygen species (ROS) level during seed germination, and the accumulation of ROS was significantly delayed in the aged seeds of Ossaur33 mutants in comparison with WT during seed germination.  Hydrogen peroxide (H₂O₂) treatments promoted the vigor of aged seeds in various rice varieties.  Our results provide timely theoretical and technical insights for the trait improvement of seed aging tolerance in rice.

Rong 6 you 5970 is a hybrid indica rice variety developed by combining the sterile line Rong 6A with the restorer line Dehui 5970. It has the characteristics of high yield, excellent rice quality, and moderate growth period. The high-yield seed production techniques of this variety were summarized and analyzed in the Deyang area of Sichuan Province, based on the characteristics of its parents. Its female parent Rong 6A generally has high compatibility, complete sterility, and excellent rice quality; Its male parent Dehui 5970 has a large amount of pollen, strong resilience, and good compatibility. The high-yield seed production technology includes selecting suitable seed production bases, selecting spatial or temporal isolation based on the situation of rhizosphere fields; reasonably arrange the sowing period for parents, scientific management of paddy fields and cultivation of strong seedlings, timely transplanting and reasonable dense planting, scientific fertilization and water management to prevent diseases and pests, flowering period regulation, reasonably spraying plant hormones, timely powder removal, strict impurity removal, and timely harvesting. The research results provide references for high yield seed production of this variety.

To scientifically guide the planting and management of regenerated rice and promote the promotion and application of related cultivation techniques. The cultivation practice of regenerated rice in Taoyuan County, Changde, Hunan Province was combined, the specific key points of its “six suitability and three high” cultivation techniques were summarized and analyzed. This technology was developed by suitable varieties (selecting rice varieties with suitable growth periods, good comprehensive resistance, excellent rice quality, and high annual yield), timely sowing (ensuring full heading before the arrival of cold dew winds during the regeneration season), moderate planting (field planting amount of 26.25-30.00 kg/hm²), suitable management (scientific water management, rational fertilization, prevention and control of diseases, pests and weeds, and timely harvestiong), suitable machinery (choosing specialized harvesting machinery for regenerated rice or replace narrow tracks to reduce the area of rice pile compaction), and appropriate pile retention (regenerated rice emergence was affected by factors such as temperature and variety characteristics, with a suitable pile height of 20-40 cm). Based on the current situation of regenerated rice cultivation in the research area from 2020 to 2023, through the application of this technology,the high yield, high quality, and high efficiency of regenerated rice have been achieved. The research results provide references for promoting sustainable production of regenerated rice.

The rice industry is one of the important industries for grain production in Southern Anhui Province. The current situation of rice production was analyzed in 4 aspects including production comparative efficiency, infrastructure, technical manpower, and enterprise driving force, and the targeted strategies were proposed to promote the development of the rice industry. In terms of comparative benefits, by adjusting the industrial structure, focusing on farmland protection, improved the multiple cropping index, and leveraging the core demonstration role of high-quality rice, improved farmers’ enthusiasm for growing crops; in terms of infrastructure, protected and improved the quality of arable land by implementing high standard farmland construction and focusing on enhancing the fertility of arable land; in terms of technical manpower, focused on strengthening agriculture through science and technology, promoted high-quality varieties, strengthened scientific and technological cooperation, enhanced technical guidance, and cultivated new agricultural talents; in terms of driving force for enterprises, measures such as cultivating and strengthening leading enterprises, promoted socialized services, and ensured production factors were taken to strengthen industrial development. To effectively ensure the good development of the rice industry in Southern Anhui Province.

With the continuous improvement in rice cultivation techniques, China has maintained a high rice production level of about 210 million tons over the past decade. Direct-seeding rice cultivation technology, recognized for its efficiency and simplicity, has been favored by Chinese farmers. However, controversies persist regarding direct-seeding rice compared to transplanted rice in national-scale production. Thus, this study employed meta-analysis techniques to quantify disparities in grain yield, economic benefit, rice quality, lodging characteristic, and greenhouse gas emissions between direct-seeding rice and transplanted rice. Our results indicated that direct-seeding rice significantly reduced grain yield by an average of 6.3% relative to transplanted rice, which was main due to the reduced total spikelet (-3.8%) and filled-grain percentage (-1.8%). In different planting systems in China, the yield of direct-seeding rice had significantly decreased compared to transplanted rice, and the direct-seeding rice-induced reductions in yield of single rice (-10.9%) and late rice (-13.1%) were higher than those of middle rice (-4.8%) and early rice (-4.4%). The grain yield reductions for direct-seeding rice were from 10% to 20% in Jilin, Liaoning, Xinjiang, Ningxia, Shandong, Jiangsu, and Zhejiang provinces, meanwhile Heilongjiang and Jiangxi provinces saw reductions of 5% to 10%, but it had no significant effect in other provinces. Direct-seeding rice resulted in comparable net economic return relative to transplanted rice (p> 0.05). Direct-seeding rice reduced milled rice rate (-3.1%) and gel consistency (-3.5%), improved appearance quality (chalkiness percentage and chalkiness degree, which decreased by 25.3% and 22.5%, respectively), whereas no significant effects were observed on nutrition quality and taste value. Direct-seeding rice increased lodging index at base of the first (+12.4%) and third (+10.3%) internodes, but not at the second internode, indicating an increase in risk of lodging relative to transplanted rice. In terms of greenhouse gas emissions, direct-seeding rice fields showed reductions in methane emissions (-42.8%), global warming potential (-36.2%), and greenhouse gas intensity (-41.1%) compared to transplanted rice fields, while promoting nitrous oxide emissions (+29.1%). In addition, a review was recounted on nitrogen utilization and its loss, water and energy use efficiency, and weed incidence. Finally, the recommendations for the future advancement of direct-seeding rice were proposed, main focusing on rice variety breeding, rice cultivation technique optimization, rice planting area layout, as well as policies and services with the goal of technological innovation and regionalized application of direct-seeding rice cultivation technology in China.

【Objective】This study aimed to explore the physiological mechanism of silicon alleviating aluminum toxicity in plants, to study the effect of biomineralization structure constructed on rice root border cells and root tips on aluminum stress, so as to provide the theoretical and practical guidance for acid soil mineralization to alleviate aluminum toxicity of plants in southern China. 【Method】Employing rice (Oryza.Sativa L.) as the experimental materials, using root tips and root border cells as the research object, under 100 μmol·L^-1 aluminum stress treatment, polyethylenimine induced nano silica to form biomineralization structure on the surface of root tips and root border cells. Four treatments are administered: bare cells without aluminum stress (-Si-Al), bare cells with aluminum stress (-Si+Al), silica-coated cells without aluminum stress (+Si-Al), and silica-coated cells with aluminum stress (+Si+Al). The study examined the cell viability, levels of active oxygen species, and localization of active aluminum in root border cells, as well as the relative elongation of the root tips, levels of active oxygen species, callose content and localization of active aluminum in the root tips. 【Result】Under aluminum stress, compared with non biomineralization, polyethylenimine induced nano silica deposition on the cell wall of root border cells, so the survival rate of root border cells increased by 21.04%, the level of reactive oxygen species decreased by 87.65%, and the relative fluorescence value increased by 77.09% after Morin staining, and then effectively improved cell survival rate, reduced ROS production, and slowed down the programmed cell death; after polyethylenimine induced nano silica deposition in root tip, the relative growth rate of root tip increased by 26.95%, the level of reactive oxygen species decreased by 27.73%, the content of callose increased by 55.29%, and the relative fluorescence value increased by 55.45% after Morin staining, hematoxylin staining also showed that more Al³⁺ was deposited in the meristematic and transitional zones of root tip, and this indicated that the biomineralization deposition could adsorb more Al³⁺ on the surface of root tip, prevent Al³⁺ from entering the root tip to protect, and then alleviate the toxic effect of aluminum on root tip. 【Conclusion】Polyethylenimine induced nano silica deposition on the cell wall endows rice root border cells and root tips with aluminum tolerance, and reduced aluminum accumulation in rice, thus ensuring food safety and human health.

【Objective】The analysis of rice yield, nitrogen use efficiency and the quantitative relationship between apparent nitrogen balance and soil alkali-hydrolyzed nitrogen under different nitrogen fertilizer management conditions could provide a more comprehensive understanding of the effects of long-term fertilization on soil fertility, so as to provide the theoretical guidance for efficient production and scientific nitrogen management of red soil paddy fields. 【Method】Based on the red soil double cropping rice long-term fertilization positioning experiment (started in 1981, located in Jinxian County, Jiangxi Province), five treatments were selected: no fertilizer (CK), nitrogen and phosphorus fertilizer (NP), nitrogen and potassium fertilizer (NK), nitrogen, phosphorus and potassium fertilizer (NPK), nitrogen, phosphorus and organic fertilizer (NPKM), and then the grain and straw yield and nitrogen uptake of rice in each season were investigated and analyzed, and the soil alkali-hydrolyzed nitrogen content was analyzed after late rice. The nitrogen uptake, nitrogen utilization rate, nitrogen apparent balance and the changes of soil alkali-hydrolyzed nitrogen were calculated and analyzed on a 10-year basis. 【Result】During the 40 years of experiment (1981-2020), the rice yield and nitrogen uptake under NPKM treatment were the highest, increased by 65.9%-108.4% and 85.1%-132.5% compared with CK, respectively, and increased by 19.3%-92.1% and 19.4%-99.8% compared with fertilizer treatments (NPK, NK and NP), respectively, showing significant differences. With the increase of the experimental period, the nitrogen use efficiency of fertilizer treatment gradually decreased, and the NPKM treatment also showed a decreasing trend in the first 30 years (1981-2010), but the rate was slower than that of fertilizer treatment, and increased in the recent 10 years (2011-2020), and from the lowest in the first 10 years (1981-1990) to the highest in the recent 10 years, increased by 25.3%-271.2% compared with fertilizer treatment. The nitrogen surplus was the highest under NPKM treatment during the 40 years of experiment, with an increase of 137.1%-577.2% compared with fertilizer treatment, but in the last 30 years (1991-2020), the nitrogen surplus gradually decreased with the increase of the experimental period. The soil alkaline hydrolyzed nitrogen content was the highest under NPKM treatment during the 40 years of experiment, increased by 7.1%-24.4% compared with CK, but the difference was not significant in the first 10 years, and increased by 11.0%-35.2% compared with fertilizer treatment, while there was no significant difference between fertilizer treatment and CK. Correlation analysis showed that the nitrogen surplus was significantly positively correlated with the soil alkaline hydrolyzed nitrogen content in the last 20 years (2001-2020). 【Conclusion】In the red soil double-cropping rice system, with the increase of fertilization years, the combined application of organic and inorganic fertilizers had better effects on rice yield, nitrogen uptake, nitrogen uptake and utilization, and soil alkali-hydrolyzed nitrogen content. Meanwhile, the increase of nitrogen surplus caused by long-term fertilization also further increased the soil alkali-hydrolyzed nitrogen content in the topsoil. The contribution capacity of nitrogen surplus to soil alkali-hydrolyzed nitrogen increased gradually.

The objective of this study is to investigate the optimal sowing time for grain filling and yield formation in black rice, thereby providing both theoretical and practical foundations for its production. The effects of different sowing dates on the growth process, grain filling characteristics, and yield trait of black rice varieties ‘Heinuo’, ‘Lirenzi’, and ‘Yanzinuo 35’ were analyzed using five experimental sowing dates. The results indicated that the overall growth period of black rice varieties was reduced by an average of 12.7-30.3 days with delayed sowing dates. The Logistic equation model was applicable to grain filling dynamics of black rice (R²≥0.995, P<0.01). Grain filling characteristics and yield composition resulted from a combination of factors including sowing date, variety selection, and their interactions. Sowing dates ranged from March 1 to June 1，the grain weight and yield per plant significantly decreased by 1.32-2.15 g/1000grain and 9.12-16.08 g. From June 1 to July 1, the grain weight and yield per plant increased by 2.13 g/1000grain and 5.97 g. The results of the path analysis revealed that increasing grain filling duration was crucial for enhancing grain weight, while the decrease in both the number of filled grains per panicle and 1000-grain weight was the primary cause of yield reduction. Adjusting sowing dates earlier or later can prolong the filling duration and increase the number of filled grain per panicle, 1000-grain weight, and seed setting rate. Sowing black rice in early March or late June is favorable for prolonging the grain filling period and enhancing both grain weight and yield.

To study the effect of the application of soil amendment on the Cd availability in soil and the Cd content in brown rice, a continuous three-year field experiment was conducted in two different textures of Cd contaminated paddy soil in Xiaojia Town, Hengyang City, Hunan Province. The results indicated that: (1) continuous application of soil amendment (2250 kg/hm² and 3000 kg/hm²) for three years significantly increased the paddy soil pH in Jinxing Village and Niuling Village, and reduced the content of available Cd in soil by 14.1%-50.0% and 16.9%-49.4%, respectively; (2) continuous application of soil amendment for three years significantly increased the rice yield in Jinxing Village and Niuling Village, and reduced the Cd content in brown rice by 40.4%-62.9% and 40.0%-64.1%, respectively. Moreover, the Cd content in brown rice in both areas was 0.15-0.18 mg/kg under the treatment of applying 3000 kg/hm² amendment, lower than the National Standards for Food Safety (GB2762—2022); (3) the net income of farmers in both areas increased significantly by 1603-2912 and 2282-3408 yuan/hm², respectively, under the treatment of applying 3000 kg/hm² amendment. Therefore, the application of soil amendment was a remediation technology that can achieve safe production in mildly Cd contaminated paddy soil.

To accurately identify pathogen of rice seedling blight and make its taxonomic status clear, the identification was carried out using morphology examination and net BLAST based on rDNA ITS sequences, the differences on rDNA ITS sequences of the rice seedling blight fungus and its related fungi from the same genus were compared, and the phylogenetic analysis was carried out. The result revealed that the pathogen of rice seedling blight was Fusarium graminearum. The differences of bases were at the sites of 92, 129, 150, 390, 394-397, 399, 401, 403, 405, 408 and 418-419 regions of rDNA ITS sequences on the pathogen of rice seedling blight and F. sporotrichioides, which was its nearer fungi from the same genus. The results of phylogenetic analysis revealed that rice seedling blight fungus clustered with F. graminearumand, and kept a nearer phylogenetic relationship with F. sporotrichioides. Fungi from the 6 genera clustered as 2 groups, and Fusarium had the nearest phylogenetic relationship with Trichoderma.