This study aims to assess the salt tolerance of perennial rice varieties (lines) ‘PR23’, ‘PR24’, ‘PR25’, ‘PR26’, ‘PR101’, ‘PR107’, and ‘PR109’, and to screen out elite salt-tolerant germplasm. The experiment employed NaCl solutions at concentrations of 0, 50, 100, 150, and 200 mmol/L to conduct salinity stress treatments on perennial rice varieties (lines) and the parent ‘RD23’. The vitality parameters (seedling height, root length, fresh weight, dry weight, etc.) and salt tolerance coefficients of varieties were determined under different NaCl concentrations. Principal component analysis (PCA) and the membership function method were used to comprehensively evaluate the salt tolerance performance of the varieties (lines). The results showed that: (1) significant differences in salt damage levels among varieties (lines) were observed when NaCl concentration reached 150 mmol/L. Among all the phenotypic traits associated with salt stress, except for root length, all other traits under the 150 mmol/L NaCl treatment showed significant differences from the control group (P < 0.05), establishing this concentration as the optimal level for screening salt tolerance in perennial rice during the seedling stage. (2) PCA of the relative values of salt tolerance traits under the 150 mmol/L NaCl treatment generated membership function values. Combining with the principal component variance contribution rate weight, the comprehensive evaluation D value was obtained, showing that ‘Yun Da 107 (PR107) ’exhibited the strongest comprehensive salt tolerance ability at the seedling stage, while ‘PR101’ showed the weakest salt tolerance capacity. Other varieties (lines) had intermediate salt tolerance levels. This study provides high-quality germplasm resources for rice salt tolerance breeding and lays the foundation for future improvements in rice salt tolerance. This study not only identifies elite salt-tolerant rice germplasm resources through phenotypic and genotypic assessments, laying a foundation for genetic improvement of rice salt tolerance, but also provides critical data support for further research on salinity stress tolerance mechanisms.

To optimize the pesticide application parameters of plant protection drones, this study systematically evaluated the effects of different water application rates on the control efficacy against rice sheath blight and the economic benefits, aiming to provide a scientific basis for precise drone-based pesticide application. Using the DJI T40 drone, field experiments were conducted in Songjiang District, Shanghai, from 2023 to 2024. Three water application rate gradients (30, 45, and 67.5 L/hm²) were set, with pesticides applying at the jointing and heading stages of rice, and the control efficacy in terms of diseased plant rate and disease index was monitored. (1) At the jointing stage, there were no significant differences in control efficacy among the gradients (diseased plant control efficacy: 85.57%-87.68%; disease index control efficacy: 89.86%-91.34%). (2) At the heading stage, the control efficacy at 30 L/hm² was significantly lower than that at other gradients (P< 0.05), while there was no significant difference between 45 L/hm² and 67.5 L/hm² (P>0.05). In 2023, the diseased plant control efficacy ranged from 79.71% to 91.99%, and the disease index control efficacy ranged from 89.47% to 94.95%. In 2024, 7 days after pesticide application, the diseased plant control efficacy was 78.86%-95.01%, and the disease index control efficacy was 85.30%-94.93%; 15 days after application, the diseased plant control efficacy was 73.17%-93.12%, and the disease index control efficacy was 77.38%-92.46%. (3) In terms of economic benefits, the operation efficiency showed a decreasing trend with the increase of water application rate (30L: 4.0 hm² /h→67.5 L: 2.67 hm² /h), and the control cost increased by 71.4% with the increase of water application rate (from 1050 to 1800 yuan per application). A differentiated water application strategy is recommended: since the water application rate at the jointing stage has no significant impact on the control efficacy, 30 L/hm² is recommended (balancing efficiency and cost); as the water application rate at the heading stage has a significant impact on the control efficacy, 45 L/hm² is preferred (balancing control efficacy and economy).

The objective of this study is to explore the agro meteorological conditions and suitable climatic zoning of rice cultivation under the complex mountainous terrain of Zhijin County. The correlation between rice meteorological yield and meteorological factors was analyzed by mathematical statistics, the key meteorological factors affecting the growth and development of rice were screened out, a localized rice meteorological yield forecast model was established, and the forecast results were tested. At the same time, according to the meteorological data and disaster weather data, combined with various disaster indicators, the zoning map of rice planting suitability in Zhijin County was comprehensively drawn. The result showed that eight meteorological factors, including average temperature and sunshine hours in late May, precipitation in late June, precipitation and sunshine hours in mid-July, average temperature and precipitation in early August, and precipitation in early September, had the best correlation with the growth and development of rice in Zhijin County. The average forecast accuracy of the established localized forecasting model is more than 90%, and the forecast results are credible, which is suitable for localized yield forecasting. The zoning map of rice climate suitability showed that the climate of southern and western townships in the central part of Zhijin County was the most suitable for rice planting, while the suitability of rice planting in the northern and eastern towns was poor. The prediction model established in this study has good prediction ability for rice yield in Zhijin County. The generated climate suitability zoning map clearly reveals regional differences, which can provide an intuitive decision-making basis for optimizing local rice planting layout, avoiding meteorological disaster risk and improving yield level.

The aim is to explore the effects of nitrogen fertilizer management on the yield and its constituent factors of ‘Chaoyou 1000’, and clarify the proportion of nitrogen fertilizer management and the yield increase mechanism of rice with high yield. Eight kinds of nitrogen fertilizer management treatments, including N₀ (no fertilization), N₁ (7:3), N₂ (6:4), N₃ (5:5), N₄ (4:6), N₅ (3:7), N₆ (2:8) and N₇(0:10), were used to study the effects of nitrogen fertilizer management on rice yield and yield components, leaf area index and dry matter with N₃ as the control. The results showed that the backward movement of nitrogen fertilizer increased the effective spike number, grain number per spike and nitrogen fertilizer agronomic efficiency, but had little effect on 1000-grain weight and seed setting rate. Under N₆, the yield and nitrogen agronomic efficiency were the highest, and the leaf area index reached the maximum value at the full heading stage. With the increase of nitrogen fertilizer backward migration at the critical leaf age, jointing stage and full heading stage of effective tillering, the leaf area index first increased, then decreased and then increased. The dry matter accumulation from full heading stage to maturity stage, the population growth rate increased first and then decreased with the increase of nitrogen fertilizer backward migration, and the harvest index gradually increased with the increase of nitrogen fertilizer backward migration. When the total amount of nitrogen application (pure nitrogen) was 420 kg/hm², the basic seedling was 28.95×10⁴/hm², and the transplanting density was 11.5 cm×30 cm, the ratio of nitrogen fertilizer was basal tiller: panicle fertilizer = 2:8, which was the most conducive to high yield.

This study explores the genetic basis and related functional genes of rice nitrogen use efficiency (NUE), highlighting the overuse of nitrogen fertilizers and summarizing the pertinent genes. NUE traits are divided into physiological traits (such as nitrogen uptake) and agronomic traits (such as tiller number) to elucidate key genes beneficial for nitrogen absorption. In physiological traits, genes affecting the absorption of NH₄⁺ and NO₃^- in rice are summarized. The absorption of NH₄⁺ in rice is primarily controlled by the AMT superfamily of proteins, whereas the proteins involved in NO₃^- transport mainly fall into two categories: NRT1 and NRT2, such as overexpression of genes like OsAMT1.1 and OsNRT1.1B can increase rice's nitrogen uptake. In agronomic traits, transcription factors such as GRF4 and NGR5 regulate the expression of nitrogen metabolism genes, promoting tiller development and grain growth, thus enhancing nitrogen use efficiency. These findings provide new genetic resources for rice breeding, promising the development of high NUE and environmentally friendly new varieties.

The research progress in rice germplasm innovation, variety breeding, and breeding technology development in Anhui Province since 1949 has been reviewed, and the future research directions in rice breeding have been prospected. In terms of germplasm innovation and variety breeding, Anhui rice germplasm (variety) innovation has gone through the stages of introducing and systematically selecting agricultural varieties and dwarf varieties, as well as selecting three-line sterile lines and two-line sterile lines; as of 2024, there were 1 539 self bred rice varieties in the research area, including three-line hybrid rice varieties such as 80 You 121, Xieyou 57, and Quanyou 822, two-line hybrid rice combinations such as Xingliangyou No.6 and Wandao 153, conventional rice varieties such as Huixiangruan No.1 and Huixiangjing 977, as well as strong drought resistant varieties such as Lyuhan No.1 and Lyuhanliangyou 21. In terms of breeding technology, mutagenesis technology has the characteristics of high mutation rate and light biological damage, enriched breeding resources; molecular marker assisted breeding technology can accurately select and efficiently recombine for the gene, improving the success rate of breeding; gene editing technology can precisely modify target genes according to specific breeding needs, further improving the precision and efficiency of breeding. The next step will focus on cultivating new varieties of green, high quality, high yielding, and multi resistant rice to meet diversified market demands.

The mycelial growth rate method was used to determine the sensitivity of 4 major rice disease (bakanae disease, sheath blight, helminthosporium leaf spot, rice blast) pathogens to 6 fungicides (20% tricyclazole, 25% kresoxim-methyl, 25% phenamacril, 20% propiconazole, 20% zinc thiazole, 125 g/L epoxiconazole). The results indicated that 25% kresoxim-methyl and 125 g/L epoxiconazole exhibited strong inhibitory effects against bakanae disease and sheath blight pathogen, with median effective concentration (EC₅₀) both below 1 mg/L; the best fungicides for inhibiting rice sesame leaf spot pathogen were 20% propiconazole and 25% kresoxim-methyl, with EC₅₀ values of 0.000 7 and 0.003 5 mg/L, respectively; the fungicides with good inhibitory effects on rice blas fungicide were 25% kresoxim-methyl and 125g/L epoxiconazole, with EC₅₀ of 1.001 1 and 1.862 1 mg/L, respectively. Overall, all 6 fungicides had inhibitory effects on rice diseases. The fungicides with better inhibitory effects are 125 g/L epoxiconazole and 25% kresoxim-methyl. It is recommended to apply them in a mixed or alternating manner in production to avoid pathogens developing drug resistance.

Based on the occurrence and damage of the main rice diseases and insect pests, the comprehensive control technologies, including agricultural, biological, physical and chemical prevention and control were discussed. The primary diseases included rice blast (which infected leaves, nodes, and panicles), sheath blight (which infected basal leaf sheaths), and false smut (a panicle disease). The major pests included rice planthopper (which sucked sap), the rice leaf roller (which damaged leaves by rolling), and rice stem borers (which bored into stems). The integrated control was centered on the ecosystem and combined agricultural, biological, physical, and chemical technologies. Agricultural control involved selecting resistant varieties and implementing scientific field management; biological control generally utilized natural enemies and integrated crop-aquaculture systems; physical control often employed measures such as trapping and barrier methods; chemical control was focused on reducing application quantities and increasing efficiency by selecting low-toxicity agents. By comprehensively applying these control technologies, precise prediction and green management were achieved, which protected rice yield and quality and promoted sustainable agricultural development.

Leaves and glumes act as lateral organs and have essential effects on photosynthesis and seed morphology, thus affecting yield.  However, the molecular mechanisms controlling their polarity development in rice still need further study.  Here, we isolated a polarity defect of lateral organs1 (pdl1) mutant in rice, which exhibits twisted/filamentous-shaped leaves and cracked/filamentous-shaped lemmas caused by defects in polarity development.  PDL1 encodes a SUPPRESSOR OF GENE SILENCING 3 protein localized in the cytoplasmic granules.  PDL1 is expressed in the shoot apical meristem, inflorescence meristem, floral meristem, and lateral organs including leaves and floral organs.  PDL1 is involved in the synthesis of tasiR-ARF, which may subsequently modulate the expression of OsARFs.  Meanwhile, the expression levels of abaxial miR165/166 and the adaxial identity genes OSHBs were respectively increased and reduced significantly.  The results of this study clarify the molecular mechanism by which PDL1-mediated tasiR-ARF synthesis regulates the lateral organ polarity development in rice.

Adjustment of the sowing date is a widely used measure in rice production for adapting to high-temperature conditions.  However, the impact of a delayed sowing date (DS) on rice quality may vary by variety and ecological conditions.  In this study, we conducted experiments using four different sowing dates, the conventional sowing date 1 (CS1), CS2 (10 d later than CS1), DS1 (30 d later than CS1), and DS2 (30 d later than CS2), and three rice varieties, i.e., Yixiangyou 2115, Fyou 498, and Chuanyou 6203.  This experiment was conducted at four sites in the Sichuan Basin in 2018 and 2019 to evaluate the influence of DS on the pasting properties of rice, which are a proxy for the eating and cooking quality (ECQ).  In DS1 and DS2, the rice had a significantly greater amylose content (AC) but a lower protein content (PC), peak viscosity (PKV), cool paste viscosity (CPV), and hot paste viscosity (HPV) than in CS1 and CS2.  Moreover, except for CS2 and DS1 in 2018, DS1 and DS2 led to 2.15–11.19% reductions in breakdown viscosity (BDV) and 23.46–108.47% increases in setback viscosity (SBV).  However, the influence of DS on rice pasting properties varied by study site and rice variety.  In 2019, DS1 and DS2 led to BDV reductions of 2.35–9.33, 2.61–8.61, 10.03–17.78, and 2.06–8.93%, and SBV increases of 2.32–60.93, 63.74–144.24, 55.46–91.63, and –8.28–65.37% at the Dayi, Anzhou, Nanbu, and Shehong (except for SBV in CS2 and DS1) sites, respectively.  DS resulted in greater reductions in PKV, HPV, CPV, and BDV and greater increases in the AC and SBV for Yixiangyou 2115 than for Chuanyou 6203 and Fyou 498.  The correlation analysis indicated that PKV and HPV were significantly and positively related to the mean, maximum, and minimum temperatures after heading.  These temperatures must be greater than 25.9, 31.2, and 22.3°C, respectively, to increase the relative BDV and reduce the relative SBV of rice, thereby enhancing ECQ.  In conclusion, DS might contribute to a significant deterioration in ECQ in machine-transplanted rice in the Sichuan Basin.  A mean temperature above 25.9°C after heading is required to improve the ECQ of rice.

To effectively exploit valuable selenium-rich soil resources, promote the development of selenium-rich rice industries, maximize the functional role of selenium in rice, and improve public health, this study selected 27 rice lines as experimental materials and conducted field trials in strongly acidic soil with rich organic matter and available potassium. The results showed that the selenium content of the produced rice was at a relatively low level, ranging from 0.0086 to 0.0247 mg/kg, with an average of 0.0153 mg/kg, a coefficient of variation of 0.258, and a maximum/minimum ratio as high as 2.86. The selenium enrichment coefficients of the rice lines exhibited highly significant differences due to genotype variations, and were generally low, ranging only from 0.0169 to 0.0484, with an average of 0.0299. The average selenium content in rice was only 61.2% of the national average, significantly lower than that in other selenium-rich rice-growing regions. All tested rice lines exhibited selenium deficiency, which is relatively rare in similar studies. This indicates that, in addition to rice genotype, soil properties also have a considerable influence on the selenium enrichment capacity of rice. Therefore, attention should be paid to the reshaping effect of spatiotemporal ecological changes on rice selenium enrichment.

【Objective】The application of chemical fertilizers and organic materials is a crucial measure for increasing agricultural production. Rice-rapeseed rotation system is a primary paddy-upland crop rotation pattern in the Yangtze River basin of China. Clarifying the impact of chemical fertilizers and organic material inputs on the annual crop yield and nutrient utilization in rice-rapeseed rotation could provide a scientific basis for ensuring food and oil security and achieving green and sustainable agricultural development. 【Method】From 2017 to 2022, a continuous field experiment was conducted at the Huazhong Agricultural University's Shayang Experimental Station in Shayang County, Hubei Province. Four treatments were established: no fertilizer (CK), chemical fertilizer only (NPK), chemical fertilizer with straw return (NPK+S), and chemical fertilizer with straw return plus organic fertilizer (NPK+S+M). The crop yields, nitrogen (N), phosphorus (P) and potassium (K) nutrient absorption of rapeseed and rice were analyzed. The nutrient use efficiency, apparent nutrient balances, and their relationships with yield were also assessed.【Result】The average results over 6 years showed that compared with no fertilization, the application of chemical fertilizers and organic materials significantly increased the yield of rapeseed (493.5%-758.8%) and rice (94.3%-106.4%), and enhanced crop yield stability (24.6%-72.1%) and sustainability (17.2%-85.0%). Compared with the NPK treatment, the NPK+S treatment increased the yield of rapeseed by 6.3%, but decreased yield stability and sustainability; it decreased the yield of rice by 0.8%, but increased yield stability and sustainability. The NPK+S+M treatment increased the yield of rapeseed and rice by 44.7% and 5.4%, respectively, and improved the sustainability of yield. Throughout the rotation cycle, nutrient uptake by rapeseed was consistently lower than that by rice across all treatments. The addition of organic materials significantly enhanced nutrient uptake in both rapeseed and rice. Relative to the NPK treatment, the NPK+S+M treatment resulted in increases of 5.1%-91.2% in average nutrient uptake and 12.2%-100.4% in trend nutrient uptake. The NPK+S treatment did not significantly differ from the NPK treatment in average nutrient uptake but exhibited a 7.7%-25.4% higher trend nutrient uptake. The input of organic materials decreased the physiological nutrient use efficiency of rapeseed and rice. Compared with the NPK treatment, the physiological N use efficiency of rapeseed and rice in the NPK+S+M treatment decreased by 3.0 and 3.7 percentage points, respectively, and the physiological P use efficiency decreased by 19.3 and 25.5 percentage points, respectively. Further analysis revealed that the application of organic materials led to higher apparent nutrient surpluses, which caused the annual increase in the cumulative yield of crops in the rice-rapeseed rotation. The cumulative apparent nutrient surplus was significantly positively correlated with the cumulative crop yield. 【Conclusion】The application of chemical fertilizers and organic materials significantly increased crop yields and nutrient use efficiency, and its effects were jointly influenced by crop and nutrient type. Increasing organic fertilization along with chemical fertilizers and straw application could further enhance soil fertility and increase crop yield; however, efforts should focus on improving the physiological nutrient use efficiency to fully realize the potential of organic amendments for sustainable grain and oil production.

【Objective】The aim of this study is to elucidate the long-term effects of tillage practices and fertilization measures on annual crop yield and nutrient utilization in a rapeseed- rice rotation system in the Yangtze River Basin, for providing a scientific basis for sustainable nutrient management to achieve synergistic grain and oilseed production in the region.【Method】Based on a site-specific field experiment (2016-2023) with a rice-rapeseed rotation system, a split-plot design was adopted. The main treatments were different tillage methods: rotary tillage (RT, 12 cm depth) and deep tillage (DT, 20 cm depth). The sub-treatments included three fertilization regimes: no fertilization (CK), chemical fertilizer alone (F), and combined organic-inorganic fertilization (FM, where chemical fertilizer in the rice season matched the F treatment, while the rapeseed season received organic-chemical fertilization). This study analyzed the rapeseed and rice yields, nutrient uptake, and nutrient use efficiency, with a comprehensive evaluation incorporating yield stability index (YSI) and sustainability index (SYI).【Result】Compared with CK, fertilization application significantly increased rice and rapeseed yields by 47.6% and 288.1%, respectively, while improving yield stability (YSI increased by 6.1% and 10.6%) and sustainability (SYI increased by 14.7% and 16.7%). Fertilization was the primary factor influencing crop yield, with FM outperforming F. DT further enhanced rice (9.2%) and rapeseed (7.0%) yields compared with RT, while significantly improving rice and rapeseed yield stability (YSI decreased by 17.9% and 4.7%, respectively) and sustainability (SYI increased by 5.7% and 7.7%, respectively). Among all treatments, FM-DT achieved the highest yields, stability, and sustainability for both crops. Further analysis revealed that FM-DT most effectively promoted nutrient translocation to grains, increasing N and phosphorus (P) harvest indices. The N and P harvest indices reached 76.9% and 76.0% in rice and 68.5% and 69.5% in rapeseed, respectively. Organic fertilizer substitution reduced chemical fertilizer input but enhanced N and P use efficiency, increasing them by 23.1% and 24.5% in rice and 63.7% and 22.8% in rapeseed, respectively. DT combined with organic substitution further improved N and P apparent recovery efficiency. 【Conclusion】The integration of FM with DT significantly enhanced productivity, stability, and sustainability in the rice-rapeseed rotation system while improving nutrient use efficiency. This approach represented an effective nutrient management strategy for achieving sustainable development in rice-rapeseed rotation in the Yangtze River Basin.

【Objective】Rice-rapeseed rotation is an important paddy-upland crop rotation in China, and the application of nitrogen (N), phosphorus (P) and potassium (K) fertilizer plays an important role in guaranteeing high and stable crop yields. This study systematically assessed the effects of different types of nutrient inputs on the yield and nutrient utilization of the annual crop of a continuous term rotation, so as to provide a reference to the management of nutrients in rice-rapeseed rotation.【Method】A rice-rapeseed rotation field trial was carried out for 8 continuous years from 2016 to 2024, with 4 treatments of equal application of N, P and K (NPK), and no N (-N), no P (-P), and no K (-K), to analyze the yield of annual crops, yield components, nutrient utilization, and apparent balance.【Result】Imbalanced fertilization significantly reduced crop yields, compared with the NPK treatment, the -N, -P and -K treatments reduced yields by 26.7%, 36.7% and 2.8% in rice and 57.4%, 86.4% and 12.3% in rapeseed, respectively, and the reduction in the number of effective number of panicles in rice and the number of pods in rapeseed were the main reasons for the crop yields reduction. With the increase of rotation year, the cumulative crop yield under -N, -P and -K treatments gradually increased the degree of yield reduction; compared with NPK treatment, the yield stability and sustainability of rice and rapeseed were significantly reduced under -P treatment. In terms of annual nutrient allocation in crop rotation, the N, P₂O₅ and K₂O accumulation in rice was higher than that in rapeseed, and the trends of nutrient accumulation in rice, rapeseed and crop annual rotation under imbalanced fertilizer application conditions were consistent with yields. Fertilizer use efficiency analysis showed that the fertilizer contribution rates of N, P and K fertilizers were lower in rice than in rapeseed, while the agronomic efficiency of N and P fertilizers, and the recovery efficiency of P and K fertilizers were higher than those of rapeseed. From the nutrient apparent balance of the annual rotation, the nutrient surpluses of the soil in the rice season were all lower than those of the soil in the rapeseed season, and the annual rotation of the NPK treatment had surpluses of 135.1 kg N·hm^-2, 49.6 kg P₂O₅·hm^-2, and deficits of 225.1 kg K₂O·hm^-2, deficiency of a single nutrient exacerbated the surplus of other nutrients.【Conclusion】In the rice-rapeseed rotation system, the deficiency of any single essential nutrient notably diminished crop yield as well as the utilization of nutrients, and the rate of yield reduction was related to the basic soil fertility level. Under the conditions of this study, the -P treatment had the largest yield reduction, followed by the -N treatment, while the -K treatment showed the smallest reduction. The magnitude of yield reduction in rapeseed was significantly higher than that in rice. Therefore, it was necessary to pay attention to the input of N and P fertilizers to achieve high and stable crop yields, and appropriate supplementation of K fertilizer to alleviate the depletion of soil K reservoirs, in order to realize high yield, high efficiency and sustainable development of the long-term rice-rapeseed rotation system.

【Objective】To explore the potential of optimizing fertilization under rice-rapeseed rotation for increasing crop yield and efficiency in medium and low yield fields, this study analyzed the effects of optimized fertilization on yield, nutrient absorption, and soil fertility in rice-rapeseed rotation, as well as the effectiveness of rice-rapeseed rotation in improving soil fertility. This study aimed to identify fertilization strategies suitable for medium and low yield fields and the potential for improving quality and efficiency in rice-rapeseed rotation, so as to provide the theoretical guidance for reducing obstacles in medium and low yield fields, promoting efficient production in rice-rapeseed rotation, and achieving sustainable development of rice-rapeseed rotation.【Method】The experiment was conducted at the Agricultural Science Research Institute in Rugao City, Jiangsu Province from 2017 to 2024, with low yield fields as the research objects. Through small-scale experiments, no fertilization treatment (CK), no nitrogen treatment (PK), no phosphorus treatment (NK), farmer's habitual fertilization treatment (FFP), and optimized fertilization treatment (OPT) were set up. By analyzing the annual yield of crops in both water and drought seasons, the nutrient absorption of aboveground parts during maturity, and soil nutrient content, the yield change rules under different fertilization systems of rice-rapeseed rotation were clarified, and the main influencing factors were explored.【Result】During the seven year rotation period, compared with FFP, the yield and yield composition of rice and rapeseed treated with OPT were more stable with increasing rotation cycles. Compared with FFP, OPT treatment significantly increased the nitrogen and phosphorus partial productivity of rice and rapeseed, with rice showing 51.5%-73.3% and 81.8%-107.9% higher nitrogen and phosphorus partial productivity, respectively; rapeseed was 137.2%-152.3% and 89.8%-101.9% higher, respectively. During the four-year rotation period, the aboveground biomass of rice and rapeseed treated with OPT was higher than that treated with FFP. Comparing the two annual rotation periods at the beginning and end of the comparative experiment, it was found that the accumulation of nitrogen, phosphorus, and potassium in the aboveground parts of rice and rapeseed treated with OPT was higher than that under FFP treatment, and OPT treatment had a better effect on improving soil organic matter, total nitrogen, and available potassium than FFP treatment. After 7 years of rice-rapeseed rotation, the soil fertility index significantly increased (63.8%-117.2%) under all treatments. Compared with FFP treatment, the average membership degree of five soil chemical indicators in the rice season treated with OPT was higher than that under FFP treatment, and its comprehensive fertility index increased by 13.4%-19.2%. In addition, the soil phosphorus activation coefficient during the three-year rotation period was monitored, and it was found that the OPT treatment had a higher soil phosphorus activation coefficient than under FFP treatment. 【Conclusion】Compared with the traditional fertilization practices of farmers, optimizing fertilization could be achieved by optimizing fertilizer management. Based on reducing nitrogen and phosphorus fertilizer application by 40% and 50% in rice and 60% and 50% in rapeseed, stabilizing their yield composition, maintaining high biomass and nutrient absorption, and achieving stable annual yield in the rice-rapeseed intercropping system; the performance of optimized fertilization treatment in improving fertilizer utilization efficiency and soil fertility was better than that of farmers' habitual treatment. Therefore, optimizing fertilization under long-term fertilizer reduction could coordinate crop nutrient needs and nutrient supply, maintain stable or increased crop yields, and improve fertilizer utilization efficiency. Rice-rapeseed rotation could improve soil fertility in medium and low yield fields, achieve obstacle reduction in medium and low yield fields, and promote sustainable development of rice-rapeseed rotation.

【Objective】By studying the effects of nitrogen fertilizer application rates on the annual crop yields, stability, and nitrogen uptake in the rice-rapeseed rotation system, this study explored the changing trends of the appropriate annual nitrogen fertilizer application rates for rice and rapeseed, so as to provide a theoretical basis for rational fertilization in the rice-rapeseed rotation in the middle reaches of the Yangtze River region.【Method】This locational trial was located in Wuxue City, Hubei Province, and was started in 2016. In this study, eight consecutive years of field locational trials were selected from 2016 to 2024. Five nitrogen fertilizer application rate gradients of 0, 90, 180, 270, and 360 kg N·hm^-2 were set up for both crops in the two seasons. The yields and their stability, nitrogen accumulation amounts, nitrogen fertilizer use efficiency, apparent nitrogen surplus, and the annual trends of appropriate nitrogen fertilizer application rates in the rice-rapeseed rotation system were analyzed. 【Result】Nitrogen fertilization significantly enhanced crop productivity in rice-rapeseed rotation systems. Compared with the nitrogen-free treatment, in each nitrogen-applied treatment, the average annual yield of rice increased by 1 035-1 769 kg·hm^-2, with an increase range of 19.4%-33.2%. The application of nitrogen fertilizer had a significant yield-increasing effect on winter rape; compared with the nitrogen-free treatment, the average annual winter rape yield increased by 1 041-2 208 kg·hm^-2, and the yield increased by 1.3-2.8 times. Aboveground nitrogen accumulation in rice and rapeseed increased progressively with elevated N inputs, averaging 36.8-108.2 kg·hm^-2 and 43.4-139.3 kg·hm^-2 higher than that under the zero-N control, respectively. Continuous observations indicated rising trends in both N accumulation and N recovery efficiency (NRE) for both crops under continuous rotation. During the rice season, with the increase in nitrogen fertilizer application rate, compared with the previous year, the average annual increase in nitrogen accumulation increased from 2.6% to 9.8%. In the rapeseed season, the increase in nitrogen accumulation in the nitrogen-free treatment was not significant among years. After applying nitrogen fertilizer, the nitrogen accumulation increased by an average of 3.4%-5.1% annually compared with the previous year. NRE in rice remained stable during the first three years but exhibited a parabolic rise starting from the fourth year. For rapeseed, NRE under 90-270 kg N·hm^-2 N rates increased by 5.6% annually, whereas no significant improvement occurred at 360 kg N·hm^-2. Apparent N balance in the zero-N treatment consistently showed deficits, while N-surplus in fertilized plots declined annually by 3.6%-8.3% (rice) and 2.4%-6.7% (rapeseed). Systematic analysis revealed an annual increase of 2.3% in optimal N rates for rice (annual mean: 146.8 kg N·hm^-2) and 0.9% for rapeseed (annual mean: 198.0 kg N·hm^-2).【Conclusion】In the continuous rice-rapeseed rotation planting mode, it was necessary to apply fertilizers with appropriate nitrogen application rates according to the nitrogen absorption characteristics of the crops in the rotation system, and to dynamically adjust the annual nitrogen allocation amount according to the soil nitrogen status.

【Objective】The rice-rapeseed rotation is a typical paddy-upland rotation cropping pattern in the Yangtze River Basin of China. The seasonal wet-dry alternation in soil affects the transformation of soil nitrogen and the application effect of nitrogen fertilizers. From the perspective of annual rotation, this study explored the differences in the effects of nitrogen fertilizer management on crop yield and nitrogen distribution in the rice-rapeseed rotation system, so as to provide a scientific basis for the efficient utilization of annual nitrogen fertilizer in the rice-rapeseed rotation system.【Method】The field experiment was located in Wuhan, Hubei Province, and was founded in 2012. This study selected 11 consecutive rice-rapeseed rotation years from 2012 to 2023 to conduct the experiment, four nitrogen fertilizer treatments were designed in the experiment: (1) no nitrogen application in both the rapeseed and rice seasons (N0-0); (2) applying 150 kg N·hm^-2 of nitrogen fertilizer in both the rice and rapeseed seasons (N150-150); (3) adding 75 kg N·hm^-2 of nitrogen fertilizer to the rice season on the basis of treatment (2) (N225-150); (4) adding 75 kg N·hm^-2 of nitrogen fertilizer to the rapeseed season on the basis of treatment (2) (N150-225). The related indicators such as crop yield, annual system energy yield, yield components, nitrogen accumulation and soil nitrogen supply capacity were analyzed.【Result】There were differences in the response of yield and nitrogen accumulation to nitrogen fertilizer management between rapeseed and rice. When the nitrogen application rate was N150-150 in both rice and rapeseed seasons, compared with no nitrogen application, the yields of rapeseed and rice increased by an average of 207.1% and 92.4%, respectively, and the nitrogen accumulation increased by an average of 253.2% and 114.7%, respectively. Compared with the N150-150 treatment, further application of nitrogen fertilizer during the rice season increased rice and rapeseed yields by 9.6% and 6.6%, respectively, while application of nitrogen fertilizer during the rapeseed season increased yields by 4.4% and 23.7%, respectively. Nitrogen application mainly increased crop yield by increasing the number of siliques per plant in rapeseed, the number of effective panicles per area in rice, and the number of grains per panicle, with rapeseed having a higher yield increase effect. In addition, from the analysis of the annual nitrogen fertilizer yield-increasing effect in the rotation system, compared with the application of 150 kg·hm^-2 of nitrogen in both rice and rapeseed seasons, the system energy yield and nitrogen accumulation of the rotation system under N225-150 treatment increased by 8.4% and 13.5%, respectively, and those under N150-225 treatment increased by 10.6% and 18.4%, respectively; at the same time, the annual nitrogen fertilizer utilization rate in the rice season with additional nitrogen application was 2.7 percentage points lower than that in the rapeseed season with additional nitrogen application, which might be related to the fact that the soil basic nitrogen supply in the rice season was 91.1% higher than that in the rapeseed season, resulting in a lower demand for high nitrogen input.【Conclusion】Therefore, in actual production, the annual nitrogen allocation should be adjusted according to the crop nitrogen requirements and soil nitrogen supply characteristics of the rotation system. In the rapeseed season, the nitrogen fertilizer application could be appropriately increased to achieve high yield, while in the rice season, the soil nitrogen supply capacity should be fully utilized, and the nitrogen fertilizer application should be appropriately controlled to achieve stable and efficient production of the rice-rapeseed rotation system.

【Objective】The aim of this study was to investigate the effects of potassium (K) fertilizer application rates on crop productivity, K utilization, and apparent K balance under the rice-rapeseed rotation system in the Yangtze River Basin, so as to provide a scientific basis for the rational application and distribution of potassium fertilizer in the rice-rapeseed rotation system.【Method】A field experiment was carried out from 2016 in Wuxue City, Hubei Province, China. Five treatments were set up with 0 (K₀), 60 (K₆₀), 120 (K₁₂₀), 180 (K₁₈₀) and 240 (K₂₄₀) kg K₂O·hm^-2, respectively. The crop yield, K uptake, K fertilizer utilization and apparent K balance were studied from 2016 to 2024.【Result】K fertilization significantly increased crop yield and aboveground K uptake, with the increase in rapeseed yield and aboveground K uptake being greater than that of rice. Compared with K₀, K application significantly increased rice and rapeseed yield by 18.1%-32.7% and 46.7%-93.1%, respectively, and K uptake by 72.3%-240.1% and 124.6%-512.2%, respectively. K fertilization significantly reduced yield stability index of rapeseed yield by 24.2%-41.2%, and markedly increased yield sustainability index (SYI) by 23.2%-45.7%. The yield stability index of rice yield across all treatments was lower than that of rapeseed, and SYI was comparatively higher. The annual energy yield under the K₀ treatment exhibited a progressive decline with each successive year of crop rotation. The increase in rapeseed yield was primarily attributed to an increase in pod number and seed number, whereas in rice, it was mainly due to an increase in effective panicles and filled grains per panicle. As the K fertilizer application rates increased, the proportion of K uptake in rapeseed within the annual system rose, with the average K uptake ratio between rice and rapeseed being 3:2. The agronomy efficiency and the recovery efficiency of K fertilizer in rice were on average 4.5 kg·kg^-1 and 2.5 percentage points higher than those in rapeseed, respectively. Conversely, the K fertilizer dependency of rapeseed was 11.6 percentage points higher than that of rice. K application shifted the annual K apparent balance from deficit to surplus. When the K fertilizer application rate increased to 180 kg K₂O·hm^-2 during the rice season, the K balance transitioned from deficit to surplus, while in the rapeseed season, 60 kg K₂O·hm^-2 was required to achieve surplus. Fitting with a linear-plus-plateau model, the optimal K fertilizer application rates were determined to be 102 kg K₂O·hm^-2 for the rice season and 147 kg K₂O·hm^-2 for the rapeseed season. 【Conclusion】In summary, the application of potassium fertilizer increased the yield of rapeseed better than that of rice. The recommended annual potassium fertilizer application rate for the rice-rapeseed rotation system was 250 kg K₂O·hm^-2, with the fertilization ratio between the rice season and the rapeseed season being approximately 2:3.

【Objective】To address the critical constraint of soil available magnesium (Mg) deficiency on annual productivity in the rice-rapeseed rotation systems of China’s Yangtze River Basin, this study systematically investigated the effects of Mg fertilizer application rates on annual crop yield formation, nutrient uptake, and Mg balance in the soil-crop system, for providing a theoretical basis for efficient Mg management in rotation systems.【Method】Based on a field experiment initiated in 2017 at Wuxue, Hubei Province, this study selected six rotation cycles (2017-2023) with five Mg fertilizer treatments (0, 15, 30, 45, and 60 kg MgO·hm^-2 per season). The crop yield components, nutrient concentrations in different plant parts, and biomass in the rice-rapeseed rotation system were measured. Based on these measurements, crop nutrient accumulation, fertilizer use efficiency, and soil nutrient balance were calculated to clarify the magnesium requirement characteristics of crops in the rotation system and establish fertilization strategies for the rotation system.【Result】(1) Mg application significantly increased annual system productivity, with yield increments of 9.5%-23.8% for rapeseed and 2.2%-4.0% for rice. A linear-plateau model indicated the maximum yields of 2 388 kg·hm^-2 (rapeseed) and 8306 kg·hm^-2 (rice) at an annual MgO rate of 60.4 kg·hm^-2 (38.1 kg·hm^-2 for rapeseed season; 22.3 kg·hm^-2 for rice season). Yield improvements in rapeseed were attributed to increased siliques per plant and seeds per pod, while rice yield gains resulted from higher effective panicles and filled grains per panicle. (2) Mg application significantly elevated Mg concentrations in all plant parts at maturity, with smaller effects on grains. The maximum increases were 45.1% (rapeseed stem), 66.2% (pod wall), and 8.5% (seed) for rapeseed, and 14.9% (stem and leaf) and 6.5% (seed) for rice. Annual biomass and Mg accumulation increased by up to 1 820 kg·hm^-2 (8.5%) and 6.3 kg·hm^-2 (29.5%), respectively. While rice showed higher absolute biomass and Mg accumulation, rapeseed 's proportional contribution to annual Mg uptake increased with Mg application. (3) Mg fertilizer apparent utilization rate and agronomic efficiency declined with increasing application rates, with rapeseed consistently exhibiting higher utilization than rice under equivalent Mg inputs. Mg removal by crops exceeded fertilizer input below 90 kg·hm^-2 annual application, while 120 kg·hm^-2 resulted in Mg surplus. If the straw was returned to the field, Mg surplus would occur when the annual Mg fertilizer application rate was 60 kg·hm^-2.【Conclusion】The application of Mg fertilizer significantly enhanced annual crop productivity in the rice-rapeseed rotation system, with rapeseed exhibiting more pronounced demand and utilization advantages for Mg. It was recommended that the annual Mg fertilizer application rate in the rotation system be approximately 60 kg·hm^-2, with a seasonal application ratio of about 2:1 between the rapeseed and rice seasons, to achieve efficient Mg fertilizer management and to improve annual productivity.

【Objective】This study aimed to clarify the effects of long-term straw return on crop yield and soil fertility in rice-rice- rapeseed rotation, so as to provide a scientific basis for the efficient use of straw resources and fertilizer replacement and reduction technology in rice-rice-rapeseed rotation system.【Method】In this study, a positioning experiment on straw return in rice-rice- rapeseed triple cropping system were selected, which was carried out for 15 consecutive years from 2007 to 2022, and set up three treatments of conventional fertilizer application + straw not returned to the field (100%F), conventional fertilizer application + straw returned to the field (100%F+St), and fertilizer reduction of 20% + straw returned to the field (80%F+St). The effects of different fertilizer applications on crop yields, nitrogen, phosphorus and potassium nutrient accumulation and soil physico-chemical properties were investigated. Nutrient accumulation and soil physicochemical properties were analyzed to assess the annual nutrient apparent balance and soil comprehensive fertility index of rice-rice-rapeseed rotation. 【Result】The long-term straw return increased crop yield, yield stability and sustainability of the rice-rice-rapeseed rotation system, with the most significant increase in the rapeseed season. Compared with 2007-2010, the late rice and rapeseed average yields under the 100%F+St treatment in 2019-2022 increased by 28.9% and 58.7%, respectively. Compared with 100%F treatment, early rice, late rice, and rapeseed yields under 100%F+St treatment increased by an average of 7.2%, 6.9%, and 13.4%, respectively, and with an average increase in yield stability and sustainability under 100% F+St treatment of 23.6% and 12.5% in the 2019-2022 late rice season. After four consecutive years of straw return in combination with 20% fertilizer reduction, early rice, late rice, and rapeseed yields remained stable or higher than conventional fertilization. Compared with the 100%F treatment, the yields of early rice, late rice, and rapeseed under the 80%F+St treatmentincreased by 5.3%, 3.1%, and 0.8%, respectively, from 2019 to 2022. Long-term straw return (100%F+St) enhanced crop NPK nutrient accumulation and annual nutrient surpluses, and the 20% fertilizer reduction + straw return (80%F+St) treatment reduced the annual NPK surpluses of the rotation by 54.0 kg N·hm^-2, 13.7 kg P₂O₅·hm^-2, and 48.6 kg K₂O·hm^-2. Analysis of the integrated soil fertility index (IFI) of the rapeseed season and the rice season following the long-term straw return revealed that the IFI of 100%F+St treatment was 1.44 and 1.51 in rapeseed season and rice season, respectively, which was significantly increased by 6.4% and 4.3% compared with 100%F treatment, respectively. The increase in IFI was higher in the rapeseed season than in the rice season. Compared with 100%F treatment, 80%F+St treatment had no significant difference in rice season and rapeseed season, with soil IFI values of 1.29 and 1.45, respectively. The increase of IFI under 100%F+St treatment mainly depended on the increase of organic matter, total nitrogen, and available potassium content by 22.8%, 20.5%, and 13.7% in rapeseed season, and the increase of organic matter, total nitrogen, and available phosphorus content by 14.1%, 1.7%, and 4.3% in rice season, respectively.【Conclusion】In conclusion, long-term straw return to the field could improve crop yield, N, P₂O₅ and K₂O nutrient accumulation and comprehensive soil fertility index of rice-rice-rapeseed rotation system, and with the increase of the time period of returning to the field, the stability and sustainability of crop yield increased. Based on the straw return condition with 20% fertilizer reduction, crop yield and nutrient accumulation could be effectively guaranteed to be maintained or higher than the conventional fertilization level, and the sustainability and stability of yield in rice season was higher than that in rapeseed season. Therefore, a 20% reduction of chemical fertilizer in the rice season could guarantee the stable yield and high efficiency of the rice-rice-rapeseed rotation system.

【Objective】Rice-rapeseed rotation is a major cropping system in the Yangtze River basin of China. Straw utilization is a crucial issue concerning agricultural sustainable development and environmental protection. This study aimed to explore the fertilizer-based utilization methods of straw in rice-rapeseed rotation systems, so as to provide the theoretical support for enhancing productivity and achieving efficient resource utilization in such systems.【Method】This study utilized a six-year (2017-2023) field experiment under rice-rapeseed rotation. Four treatments were chosen: no straw incorporation (NPK), direct incorporation of straw in both seasons (NPK+S/S), straw biochar incorporation in both seasons (NPK+B/B), and straw biochar incorporation in the rice season combined with direct straw incorporation in the rapeseed season (NPK+B/S). Crop yield and its stability, plant N absorption and utilization efficiency as well as the apparent N balance in soil were systematically analyzed.【Result】Direct and straw biochar incorporation significantly increased crop yields and yield stability. Compared with NPK, the rapeseed yields under NPK+S/S, NPK+B/B, and NPK+B/S increased by 13.9%, 14.8%, and 17.3% on average, respectively; rice yields increased by 8.5%, 7.2%, and 3.7%, respectively; annual energy yields improved by 10.5%, 9.9%, and 8.5%, respectively. Compared with NPK, the rapeseed yield sustainability index under NPK+S/S, NPK+B/B, and NPK+B/S was enhanced by 8.1% to 10.2%. Compared with NPK+S/S, NPK+B/B and NPK+B/S were more beneficial for enhancing rice yield stability (24.2% and 1.4%, respectively) and sustainability index (5.3% and 2.3%, respectively). Both straw management practices increased crop N uptake but decreased the N harvest index. Compared with NPK, aboveground N uptake in rapeseed increased by 7.4% to 20.7%, in rice by 3.3% to 15.0%, and in the annual rotation by 6.5% to 17.6% under NPK+S/S, NPK+B/B, and NPK+B/S treatments. However, the N harvest index in rapeseed and rice decreased by 0.2%-3.0% and 1.9%-3.8%, respectively. Compared with NPK+S/S treatment, NPK+B/B treatment significantly reduced N uptake in the above-ground part of rapeseed by 11.0%. The reduction in N uptake in rapeseed grains, rice grains, and the above-ground part of rice was not significant, while the N harvest index of rapeseed and rice was increased by 1.8% and 1.9%, respectively. Direct straw incorporation had an advantage in promoting crop N uptake, while straw biochar incorporation had an advantage in improving crop N distribution. Compared with NPK, NPK+S/S, NPK+B/B, and NPK+B/S significantly increased the partial factor productivity of applied N in rapeseed (13.9% to 17.2%) and rice (2.2% to 7.7%). All treatments showed N surplus, with the NPK+B/S treatment having the highest N surplus. Compared with the NPK treatment, the NPK+S/S, NPK+B/B and NPK+B/S treatments all increased the soil total N content (20.6%-22.7%). Soil total N content was the highest under straw biochar incorporation, which was more effective in converting surplus N into soil N and reducing N loss.【Conclusion】In rice-rapeseed rotation system, considering economic effects, compared with direct straw incorporation or straw biochar incorporation in both seasons, the strategy of applying straw biochar during the rice season and directly incorporating straw during the rapeseed season could not only ensure stable high crop yields but also enhance N fertilizer utilization and increase soil total N content, providing important support for the sustainable development of rice-rapeseed rotation systems.

【Objective】This study aimed to investigate the effects of long-term different straw return methods on productivity and apparent balance of nitrogen, phosphorus and potassium nutrients in rice-rapeseed rotation system, in order to provide the theoretical basis for the efficient utilization of straw resources in the rotation system.【Method】The field experiment was located in Wuxue City, Hubei Province, and started in 2014, with three treatments of straw not return (NPK), direct straw return (NPK+St) and burning straw return (NPK+Sb), to determine and analyze the yields, nitrogen/phosphorus/potassium nutrient uptake and their apparent balances and other related indicators of rice and rapeseed in the consecutive 10-year period from 2014 to 2024.【Result】The average results of the 10-year experiment showed that compared with the NPK treatment, the rice and rapeseed yield in the NPK+St treatment increased significantly by 7.7% and 10.7%, respectively; the rapeseed yield in the NPK+Sb treatment increased significantly by 5.2%, and the effect of yield increase on rice was not significant. The yield increase effects of NPK+Sb and NPK+St increased with the increase in years of straw return, and in the 6th year reached the significant level. Based on the annual nutrient uptake characteristics, compared with the NPK treatment, the annual nitrogen uptake in the NPK+St and NPK+Sb treatments increased by an average of 11.6% and 2.9%, respectively, the annual phosphorus uptake increased by an average of 11.9% and 10.2%, respectively, and the annual potassium accumulation increased by an average of 55.8% and 39.1%, respectively. Direct straw return significantly enhanced the absorption of nitrogen, phosphorus and potassium nutrients in the rotation system. Burning straw return effectively increased the absorption of phosphorus and potassium nutrients in the rotation system. The annual nitrogen, phosphorus and potassium surplus of rice-rapeseed rotation in the NPK treatment were 101.3 kg N·hm^-2·a^-1, -8.9 kg P₂O₅·hm^-2·a^-1 and -296.6 kg K₂O·hm^-2·a^-1, respectively. The annual nitrogen surplus in the NPK+St treatment averaged 166.1 kg N·hm^-2·a^-1, with an increase of 64.0%. The annual phosphorus and potassium nutrient surpluses were realized for both NPK+St and NPK+Sb treatments, with surpluses of 33.0 and 19.0 kg P₂O₅·hm^-2·a^-1, 79.4 and 21.3 kg K₂O·hm^-2·a^-1, respectively. 【Conclusion】Direct and burning straw return significantly increased the crops production potential and nutrient uptake by promoting nutrient cycling in the rice-rapeseed rotation system. The effect of stabilizing rice yield and increasing rapeseed yield was shown among the different crops in the rotation. The straw direct return was more favorable to increase crop yield and to maintain the nutrient balance of the farmland than the straw burning return. Therefore, it was recommended to promote the direct straw return approach in the process of farmland production in order to fully utilize its advantages of yield enhancement, stabilization, and nutrient balancing, and to promote the sustainable development of the rice-oil rotation system.

This study investigates the effects of brackish water irrigation and nitrogen fertilizer types on the growth and yield of rice, providing a theoretical basis and practical guidance for integrated management of water and fertilizer as well as the improvement of crop yield in coastal saline farmlands. Taking moderately coastal saline soil (salt content=2.2 g/kg) as the test soil, a four-month field column experiment was conducted using ‘Y-Liangyou-911’ rice variety as material. The experiment was designed with two factors: the salinity of irrigation water [freshwater (W₁), mixed irrigation of freshwater and brackish water (W₂), and brackish water (W₃) alone] and nitrogen fertilizer types [urea (N₁), polyurethane-coated urea (N₂), and urea formaldehyde (N₃)]. The tillering number, plant height, leaf area as well as yield and its components of rice were analyzed. The results showed that, under the same nitrogen fertilizer type treatment, compared with fresh water irrigation (W₁), brackish water irrigation (W₂ and W₃) significantly promoted the tillering of rice, but reduced the plant height and leaf area. The nitrogen fertilizer type only significantly affected tillering number under fresh water irrigation. Specifically, the tillering number under W₁N₃ treatment was significantly higher than that under W₁N₂ and W₁N₁ treatments. However, nitrogen fertilizer type had no significant effect on plant height and leaf area. Regarding rice yield and its components, brackish water irrigation had no significant effect on the panicle number and grains per panicle, but significantly reduced the thousand-grain weight, consequently resulting in a decrease in yield. Compared with W₁ treatment, the yield under W₂ and W₃ treatments decreased by 17%-28% and 22%-35%, respectively. The nitrogen fertilizer type had no significant effect on panicle number and thousand-grain weight, but significantly increased grains per panicle and yield. Notably, compared with three treatments under fresh water irrigation, the rice yield under W₂N₂ treatment showed no significant decrease. In coastal saline areas, appropriate brackish water irrigation can promote rice tillering but inhibits plant height and leaf growth, thereby significantly reducing thousand-grain weight and causing yield reduction. Polyurethane-coated urea can effectively mitigate the negative impact of brackish water irrigation on rice yield. Overall, the practice combining the mixed irrigation with freshwater and brackish water (<1.50 g/L) and the application of polyurethane-coated urea as a basal fertilizer is an effective management strategy of water and fertilizer. This approach efficiently facilitates the utilization of brackish water resources and the stabilization of crop yield in coastal saline areas.

In this study, we focus on the genetic mechanisms underlying culm strength in rice, aiming to provide a robust theoretical foundation for molecular breeding of lodging-resistant varieties. By systematically reviewing and conducting in-depth analyses of academic literature and research reports, we explore the regulatory mechanisms of genes associated with culm strength, culm chemical composition, hormonal regulation, and plant architecture, as well as their molecular mechanisms in conferring lodging resistance. Consequently, rice culm strength is influenced by both morphological traits (e.g., basal internode diameter and culm wall thickness) and chemical components (including cellulose, hemicellulose, and lignin contents). Notably, the mechanical properties of lower internodes are key determinants of rice lodging resistance. In terms of genetics, SCM3 (an allele of OsTB1) enhances culm strength via the strigolactone signaling pathway. WAK10 regulates cellulose synthesis in secondary cell walls. OsTCP19 facilitates the balance between lignin and cellulose. IPA1 achieves synergistic improvements in lodging resistance and yield by optimizing plant architecture—specifically, by reducing ineffective tillers, increasing culm diameter, and balancing lodging resistance with an increased number of grains per panicle. In terms of breeding applications, molecular marker-assisted selection has been employed to screen for quantitative trait loci (QTLs) associated with culm strength, such as prl5 and lrt5. Additionally, gene-editing technologies (e.g., CRISPR/Cas9) have been utilized to modify key genes governing culm strength in rice lodging resistance breeding. Through backcrossing to develop near-isogenic lines (NILs), multiple strong culm genes (including SCM1-4) have been pyramided—resulting in NIL-SCM1, NIL-SCM2, NIL-SCM3, NIL-SCM4, as well as double and triple NIL combinations. This approach has enabled the successful development of lodging-resistant varieties, namely 'Sakura Prince' and 'Monster Rice 1'. This study proposes that future work should be carried out in the following aspects: mining novel lodging resistance genes (e.g., the STRONG2 module) and analyzing multi-gene synergistic effects, establishing a genetic balance model involving stem strength, panicle weight, and panicle number, optimizing gene pyramiding strategies in combination with genome-wide association analysis, and exploring the impacts of environmental factors (such as typhoons and dense planting) on culm strength. These efforts aim to achieve enhancement of rice lodging resistance and yield simultaneously.

The planting performance of Zhuliangyou 5298 was combined in Anqing City, Anhui Province area, and its high yield cultivation techniques were summarized. From 2022 to 2024, this variety was planted in 12 demonstration sites, including Wangjiang County in Anqing City, with an upright and upward curved plant shape; the growth period was 130-136 days, with an average seed setting rate of 85.77%, a thousand grain weight of 24.1 g, and a yield of 8 280-9 000 kg/hm²; good polished rice yield and excellent rice quality; strong anti lodging ability. Its high yield cultivation techniques include early sowing (sowing and seedling cultivation from late April to mid May), timely transplanting, cultivating strong seedlings, keeping the soil of the seedling field moist, applying “weaning fertilizer” (urea 60-75 kg/hm²) according to the growth of the seedlings, and timely prevention and control of seedling diseases and pests such as rice thrips and bakanae disease; select high speed rice transplanter operation based on seedling quality, planting time, etc., inspect and debug the transplanting machinery according to the settings, determine the planting distance, seedling amount, and depth; timely weed control (spraying pesticides such as butachlor for soil sealing, spraying pesticides such as butazone for stem and leaf control during the seedling stage, and spraying pesticides such as 30% propiconazole for sealing throughout the field after the seedlings); heavy application of base fertilizer (45% compound fertilizer 450-600 kg/hm²), early application of tillering fertilizer (high nitrogen and high potassium compound fertilizer 225-300 kg/hm²), and supplementary application of ear fertilizer (potassium chloride 112.5-150.0 kg/hm²); shallow water seedling planting, deep water live planting, alternating dry and wet conditions to promote tillering; appropriate pesticides should be used during the growth period of the field to prevent and control diseases and pests such as rice blast and sheath blight. This article provides a reference for further promotion and planting of this variety in similar regions.

Ratoon rice is an efficient planting model that achieves “one planting, two harvests”in rice production. Based on the production practices of ratoon rice in Ma'anshan City, Anhui Province from 2020 to 2024, the production status， influencing factors of ratoon rice and proposes corresponding development countermeasures were analyzes. From 2020 to 2024, the planting area of ratoon rice in the study area increased rapidly the dominant varieties were mainly characterized by excellent rice quality and lodging resistance (Fengliangyouxiang 1, Y Liangyou 911); the yield of ratoon rice increased steadily, with the two-crop yield per unit area in 2024 increasing by 817.5 kg/hm² compared with 2020; an integrated application and promotion system was established from the three aspects of seedling raising, fertilizer and water management, and harvesting, and innovative production models such as “two shrimps and two rice crops”, “Chinese flowering cabbage + regenerated rice” and “green manure + regenerated rice” were developed. The influencing factors of its development include high investment costs, the need for enhanced attention; the yield level of the second crop of ratoon rice needs to be improved, there are few alternative varieties of regenerative rice, and the crushing rate of the first harvest is relatively high; there are few large scale and specialized rice processing enterprises, and the development model of the entire industrial chain needs to be strengthened, etc. Based on this, targeted countermeasures are proposed from the aspects of support, technical research and market development, including increasing investment and implementing universal planting subsidies; continuing to screen special ratoon rice varieties, promoting early seedling raising in steel frame connected greenhouses, synchronous side deep fertilization with mechanical transplanting, and timely mechanical harvesting to reduce losses; accelerating the development of the local ratoon rice market, expanding the market with quality, promoting processing with the market, and promoting production with processing to effectively improve the planting benefits of ratoon rice and farmers' planting enthusiasm. This paper provides references for promoting the high quality development of ratoon rice in relevant regions.

【Objective】 Tos17 is a type of retrotransposon in the rice genome. In the japonica variety Nipponbare, a Tos17 located on chromosome 7 (Tos17^Chr.7) can be activated during tissue culture. This study aims to reveal the genomic features of Tos17 of indica varieties in China and determine whether their Tos17 can be activated in tissue culture like in japonica rice, which may affect biotechnological breeding. 【Method】 High-quality genome resequencing data of indica varieties or hybrid parents were retrieved from public databases. An in-house program was developed to identify and analyze Tos17 insertion loci, confirmed by IGV visualization and PCR assays. The varieties were classified through hierarchical clustering and principal component analysis, a phylogenetic tree was constructed based on genome-wide single nucleotide polymorphism (SNP) data, and the association between varietal clusters and Tos17 haplotypes was assessed using Mantel test. Transgenic plants were generated by Agrobacterium -mediated transformation of mature embryo-derived callus of indica varieties, and the changes of Tos17 copy number were analyzed in 125 T₀ transgenic plants.【Result】 23 distinct Tos17 insertion loci were identified in 1 511 indica varieties using the Tos17-finder, a program developed specifically for Tos17 identification. All varieties had a Tos17 on Chr.10 (Tos17^Chr.10) identical to the one in japonica rice Nipponbare, and there were two high-frequency Tos17 copies on Chr.2, i.e., Tos17^Chr.2-1 (79.0%) and Tos17^Chr.2-2 (83.7%), but only 85 (5.6%) varieties carried the Tos17^Chr.7 common to japonica rice. There were 4.0 Tos17 copies per variety on average, and while 11 varieties had up to 8 Tos17 copies, 35 only had a single Tos17, i.e., Tos17^Chr.10. Twelve Tos17 insertions were located within or 2 kb up- or down-stream of annotated genes, with the remaining 11 in intergenic regions. Phylogenetic analysis based on SNPs classified the 1 511 varieties into three subpopulations, each showing partial correlation with specific Tos17 haplotypes. No new Tos17 insertions were detected in the 125 T₀ transgenic seedlings of 5 indica varieties. A molecular marker capable of accurately distinguishing Tos17^Chr.7 from other Tos17s was developed. 【Conclusion】 The genomic features of Tos17 in indica rice varieties differ from those in japonica rice variety Nipponbare. The developed molecular marker can be used to determine readily whether the test materials carry the activatable Tos17^Chr.7.

Soil samples were collected from the tobacco-rice rotation area of southern Hunan to analyze the physical, chemical and biological characteristics of the soil. To evaluate soil quality and diagnose obstacles, providing a scientific basis for nutrient management, reduction of limiting factors, and improving the yield and quality of tobacco leaves in this region, a total of 124 soil samples were collected from 11 tobacco stations. 18 indicators, including soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), available potassium (AK), exchangeable calcium (ECa), exchangeable magnesium (EMg), available manganese (AMn), available boron (AB), available molybdenum (AMo), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP), water-soluble chloride ion (Cl), bulk density (BD) and pH, were selected as the total data set (TDS). Using principal component analysis combined with the Norm value method, a minimum data set (MDS) was constructed to derive the soil quality index (SQI). An obstacle factor diagnosis model was employed to identify the main limiting factors. The results showed that the MDS for the tobacco-rice rotation area in southern Hunan consisted of bulk density, total nitrogen, pH, microbial biomass carbon, microbial biomass nitrogen, microbial biomass phosphorus, available phosphorus, total potassium and available manganese. The MDS-based soil quality index (MDS-SQI) exhibited a highly significant positive correlation with the TDS-SQI (R²=0.479，P<0.05), with a relative deviation coefficient of 0.053. This indicated a good fit between the two indices, with minimal relative deviation, suggesting that the MDS could effectively replace the TDS for soil quality evaluation in this region. Obstacle factor analysis revealed that the main limiting factors in the tobacco-rice rotation area were total nitrogen (average obstacle degree of 0.093) and available manganese (average obstacle degree of 0.090). The established MDS evaluation method accurately reflected actual soil quality, balancing representativeness and accuracy while simplifying workload. It was suitable for soil quality evaluation and obstacle diagnosis in tobacco-rice rotation systems. The soil quality index in the tobacco-rice rotation area ranged from 0.221 to 0.614, with an average value of 0.417, indicating that overall soil quality is at a moderate level.

To explore a suitable double cropping rice combination model for the Changsha region, Hunan Province, early, medium, and late maturing hybrid rice varieties (early rice: Xinrongyou 123, Lingliangyou 1785, Bingliangyou 309; late rice: Hengfengyoujinsimiao, Taiyounong 39, and Yliangyou 911) were respectively planted in Beisheng Town of Liuyang City(A), Chunhua Town of Changsha County(B), Bairuopu Town of Xiangjiang New Area(C), and Huilongpu Town of Ningxiang City(D). Their growth periods, yield, ecological adaptability, and benefits were measured. The results indicated that different maturity combinations could successfully complete the growth process in all double cropping rice regions; there were differences in the yield of early and late rice, as well as the total yield of double cropping, among different double cropping rice regions. The yield of late rice was higher than that of early rice, indicating that the stability and ecological adaptability of late rice yield were stronger; the economic benefits of planting in the late maturing early rice+late maturing late rice model were the highest, followed by the medium maturing early rice+late maturing late rice, late maturing early rice+medium maturing late rice model. Overall, the combination of late maturing early rice and late maturing late rice had higher yield and economic benefits in different double cropping rice regions in the study area; however, late rice had a longer growth period and was easily affected by cold dew winds, which poses a risk to safe heading and may lead to unstable yield. Therefore, it was recommended that various regions adopt a combination of medium maturing early rice and late maturing late rice according to local conditions, and adopt green high yield cultivation techniques such as reasonable close planting and formula fertilization to achieve the balanced yield increase of the two cropping rice.

To promote the reduction and increase efficiency of chemical fertilizers and improve the production capacity of ratoon rice, a bio-fertilizer experiment was carried out in Guichi District, Chizhou City, Anhui Province. 6 treatments were set up (A, bio-organic fertilizer 7 500 kg/hm²+nitrogen energy compound fertilizer 450 kg/hm²+nitrogen energy urea 150 kg/hm²; B, bio-organic fertilizer 5 250 kg/hm²+nitrogen energy compound fertilizer 450 kg/hm²+nitrogen energy urea 150 kg/hm²; C, bio-organic fertilizer 3 000 kg/hm²+nitrogen energy compound fertilizer 450 kg/hm²+nitrogen energy urea 150 kg/hm²; D, bio-organic fertilizer 5 250 kg/hm²; E, nitrogen energy compound fertilizer 450 kg/hm²+nitrogen energy urea 150 kg/hm² ; F, without fertilization), the tillering dynamics, yield, and planting benefits of rice in each treatment were analyzed. The results showed that the combination of bio-organic fertilizer and new fertilizer could improve the tillering rate and panicle formation rate of rice. The highest tillering rate of first season rice was achieved with treatment B, which was 600%. The effective number of panicles and panicle length of ratoon rice treated with treatment B were the highest, at 5.017 2 million panicles/hm², 21.08 cm, respectively, the total yield of rice was the highest, at 15 857.25 kg/hm². The economic benefit of treatment E was the highest, at 32 158.67 yuan/hm². The agronomic efficiency of fertilizer was highest in the treatment B, which was 11.73 kg/kg. At the same time, the application of bio-organic fertilizers combined with new fertilizers has improved the processing, appearance, and taste quality of rice to a certain extent. Overall, it is recommended to apply bio-organic fertilizer at a ratio of 5 250 kg/hm²+49% nitrogen energy compound fertilizer at 450 kg/hm²+46% nitrogen energy urea at 150 kg/hm², which results in better rice yield and quality, and higher economic benefits.

This paper combines the production practices of the rice-crayfish symbiotic farming model in the Ma’anshan region of Anhui Province, the technical requirements for paddy fields, the key techniques for rice cultivation and crayfish farming under this model were analyzed, as well as its advantages and future research trends. For this model, it was advisable to select field plots of 3–5 hm⊃2;, with ridge widths no less than 1.5 m and heights of 60–80 cm. Additionally, the inner slopes of the fields should be protected with polyethylene mesh fabric with a mesh size of 5 mm.The key techniques for rice cultivation included selecting varieties with plant heights above 1.1 m, strong lodging resistance, and good disease resistance (such as Wangliangyou 018, Weiliangyou 8612, and Qiaoliangyou 17), using the “day-soaking and night-draining” method for seed soaking, and employing rice-specific germination boxes for constant-temperature sprouting. The suitable sowing period in the study area is March 15–20. Greenhouse seedling cultivation mainly adopts dry management and sprinkler irrigation, with daytime temperatures maintained at 25–30 °C. Water control and seedling hardening were implemented 5–7 days before transplanting, while the main field was rotary-tilled in advance. Mechanical transplanting is adopted, ensuring sufficient basic seedlings with a planting density of 30 cm × 17 cm and 12 000–15 000 holes/667 m⊃2;. The first harvest of rice should be completed before August 20, while the ratoon rice harvest period falls between late October and early November.The key techniques for crayfish farming included stocking fry in two batches (the first from March 20 to April 20 and the second before the end of May), with a total stocking density of 7 000 individuals/667 m⊃2;. On the day of release, high quality juvenile feed with a protein content of 36% and a particle size of 1.1 mm should be evenly distributed. After release, fermented yeast-based EM bacteria should be applied every 5–7 days for water quality regulation. During the harvesting period (from May to late October), a “capture the large and retain the small” approach is adopted for flexible harvesting. This model achieves “one planting with two harvests” for rice, improving its yield, while also enhancing the unit yield and size of crayfish. The harvesting period is significantly extended, leading to notable economic benefits. Future research should further investigate the effects of rice planting density and crayfish stocking density on rice yield and farming efficiency under this model.

【Objective】Rice blast critically compromises rice production. The genetic enhancement of blast resistance remains challenging due to pathogen variability and limited genetic diversity in breeding parents. This study seeks to accelerate resistance breeding by identifying novel resistance loci through systematic germplasm characterization. 【Method】A panel of 265 sequenced indica rice accessions (including 120 international germplasms and 145 cultivars from South China) underwent field-based blast resistance evaluation. Genome-wide association study (GWAS) was subsequently employed to identify blast resistance quantitative trait loci (QTL). Haplotype effects of these QTL on blast resistance were analyzed, and candidate genes within newly identified QTL regions were predicted using rice genome annotation. 【Result】Field resistance evaluation identified 47 accessions (18 international germplasms and 29 cultivars from South China) exhibiting high resistance to both panicle and leaf blast. GWAS detected nine blast resistance QTL distributed across chromosomes 1, 5, 6, 11, and 12, respectively. Among them, four QTL was co-localized with previously reported blast resistance genes and five QTL were newly identified. Haplotype analysis revealed significant resistance variations associated with peak SNP alleles, with eight QTL showing higher frequency of resistant haplotypes in cultivars from South China compared to international germplasms. Notably, the qPB11 locus demonstrated an inverse distribution pattern, where its resistant haplotype frequency was substantially lower in cultivars from South China (1%) than in international germplasm (16%). Candidate gene analysis within novel QTL regions identified four NBS-LRR disease resistance proteins and four NB-ARC domain-containing proteins, with eight candidate genes clustered within a 27.22-27.35 Mb interval on chromosome 11.【Conclusion】Cultivars from South China exhibit superior blast resistance compared to international germplasms. The high-resistance haplotypes of qPB1-1, qPB1-2, qPB1-3, qPB5, qPB6, qPB12-1, and qLB12/qPB12-2 have been preferentially selected during the genetic improvement of cultivars from South China. Furthermore, the qPB11 locus harbors genes encoding NBS-LRR disease-resistant proteins and NB-ARC domain-containing proteins, representing new potential resistance gene for rice blast disease.

种子的落粒性和品质是维持稳定产量及确保优良食用品质的关键因素。本研究成功鉴定了一个AP2/ERF转录因子—SHAT2，该基因能正向调控种子落粒性和品质。shat2突变体由于离层发育异常，导致成熟期种子难落粒。同时，与野生型相比，shat2突变体的淀粉颗粒排列松散，总淀粉以及直链淀粉含量和蛋白质含量显著降低，而可溶性糖含量显著增加。qRT-PCR 的检测结果显示，大部分与种子落粒性以及品质相关基因在shat2突变体中表达显著下调，表明了SHAT2在水稻种子落粒性和品质中起重要作用。此外，EMSA结果显示SHAT2可以结合GCC-box，暗示SHAT2可能通过调控下游基因的表达来影响种子发育。本研究不仅丰富了遗传资源，还突显了SHAT2在培育具有理想落粒特性和优良稻米品质的水稻品种中的巨大潜力。

The purpose of this study is to explore whether tourmaline tailings can promote crop growth, realize the resource utilization of tailings, and promote the integrated development of the first, second and third industries. Using tourmaline tailings as test material, and different proportion tailings were added to the soil. The growth and physiological indexes of rice were measured by combining indoor pot experiment with laboratory analysis test. The results showed that tourmaline tailings hindered the growth of plant height, root length and leaf length of rice seedlings, which decreased by 8.7%-10.3%, 4.5%-32.0% and 8.7%-15.1%, respectively. And tourmaline tailings promoted root diameter and stem diameter of rice seedlings, increasing by 9.6%-15.4% and 0.9%-4.3%, respectively. The promotion effect of stem diameter increased with the increase of the proportion of addition. The small proportion of 1:30 was beneficial to the growth of plant height at reproductive stage, and was also beneficial to the growth of dry matter accumulation at seedling and mature stage. The dry matter of rice at seedling and maturity stage increased by 4.1% and 12.26%, respectively. The SOD activity in different growth stages and Pro content at jointing stage of rice were significantly negatively correlated with the yield, and the yield decreased by 0.1%-14.6%, which the addition of tailings was not conducive to the accumulation of rice output. The results showed that tourmaline tailings had a stress on the growth and development of rice, and did not improve the economic benefits of rice. Small proportion of tailings could promote the accumulation of dry matter in rice.

In the context of global climate change, the rice planting zoning in Keyouzhongqi Banner, Inner Mongolia was established. This article selected three highly correlated meteorological elements as zoning factors and developed climate zoning indicators for rice planting in Keyouzhongqi Banner. Based on ArcGIS geographic information system and digital elevation model, the observation data of accumulated temperature, frost free period, precipitation and other activities above 10℃ from the National Automatic Meteorological Observation Station and 42 regional automatic meteorological observation stations in Keyouzhongqi Banner from 1991 to 2020 were used. ArcGIS software was used to calculate spatial interpolation to obtain the spatial calculation conclusion of the zoning indicators. The rice planting meteorological area in Keyouzhongqi Banner was divided into three zones: suitable zone, sub suitable zone and unsuitable zone. Suitable areas should choose high-yielding, high-quality, and stress resistant mid to late maturing rice varieties with longer growth periods and high yield potential. The planting mode should adopt precision farming and large-scale planting to improve production efficiency; in the sub suitable areas, early maturing or mid maturing rice varieties with strong adaptability to drought, cold, and barrenness should be selected. The planting mode should adopt water-saving irrigation, intercropping, etc., and actively develop ecological agriculture; in unsuitable areas, rice varieties with strong stress tolerance or high resistance can be selected for improvement. In areas where rice cultivation is not suitable, measures such as converting paddy fields to dry fields can be taken to plant suitable crops. We should Strengthen land consolidation and soil improvement, gradually improve planting conditions, and develop other agricultural industries such as animal husbandry and forestry. The zoning results can provide an important basis for local optimization of rice layout, selection of suitable varieties and formulation of scientific planting strategies.

【Objective】Salt stress is one of the main environmental stresses that restrict rice production. Studying the physiological characteristics under salt stress and analysis the allelic variation and expression of salt-tolerance genes provide key gene resources and genetic materials for breeding salt-tolerance rice varieties. 【Method】This study first evaluated the salt-tolerance ability of the Nangeng series high-quality rice varieties/lines during the seedling stage, using survival rate as an indicator for screening salt-tolerance varieties, which physiological changes under salt stress were analyzed, including chlorophyll, Na⁺, K⁺, MDA, H₂O₂ and soluble sugar. The variation types and expression levels of salt-tolerance genes in rice varieties with resistance to high salt concentration were also analyzed to explaining their molecular mechanisms in response to salt stress. 【Result】Under the condition of treating with 140 mmol·L^-1 NaCl for 6 days, the survival rates of NG9108, NG5718, and NGY1 were greater than 60%, with the highest survival rate among the tested varieties. Compared with Nipponbare, the seedlings of NG9108, NG5718, and NGY1 under salt stress had higher chlorophyll content and lower MDA content, indicating that salt stress caused less cell damage to the three varieties. The Na⁺/K⁺ values in the roots of NG9108, NG5718, and NGY1 were significantly higher than those in Nipponbare, while the Na⁺/K⁺ values in the aerial parts were significantly lower than those in Nipponbare, implying that the three varieties absorb or store more Na⁺ in roots, but transport less Na⁺ upwards, which is beneficial for maintaining cell ion balance and causing less ion toxicity and osmotic stress in aerial parts of the seedlings. The three salt-tolerance varieties have 94 SNPs or InDel sites, distributing in exons, introns, 5′UTR, and 3′UTR of the 23 salt-tolerance genes. 24 variation sites of 11 genes occur in the exons, including 7 genes with frameshift mutations or missense mutations which distributed in Os02g0813500 (OsGR2), Os05g0343400 (OsWRKY53), Os06g0685700 (OsRST1), Os07g0685700 (OsEIL2), Os10g0431000 (OsPQT3), Os11g044600 (OsRSS3), Os12g0150200 (P450). Salt stress significantly induces expression of OsSKC1, OsBAG4, OsGPX1, OsCCX2, OsGR3, OsDREB2a, OsRAB21, OsP5CS, OsbZIP23, OsAPX37 and OsLEA3, which help to enhance salt tolerance and reduce the adverse effects of salt damage on rice growth. 【Conclusion】NG9108, NG5718 and NGY1 showed strong salt tolerance phenotype during the seedling growth stage, which is closely related to the balance of sodium and potassium ions under salt stress, allelic variations of multiple salt tolerance genes, and gene expression levels. NG9108, NG5718 and NGY1 have pyramided multiple salt tolerant and high-quality genes, which can be used as backbone parents for genetic improvement and breeding.

【Objective】Nitrogen panicle fertilizer is one of the key factors affecting rice yield and quality. Studying its impact on the yield, quality, and aroma of aromatic japonica rice in southern China could provide a theoretical basis for high-yield and high-quality cultivation of southern japonica rice. 【Method】 Conducted from 2022 to 2023, this study used Nanjing 9108, a representative variety of aromatic japonica rice in southern China, as the material, and three nitrogen application modes were set up: no nitrogen fertilizer (N0), no panicle fertilizer (N1), and conventional application of panicle fertilizer (N2, with 70% base and tillering fertilizer + 30% panicle fertilizer). In addition, the experiment of applying ear fertilizer at different leaf age stages, including the top sixth leaf, fifth leaf, fourth leaf, third leaf, second leaf and first leaf just after emerging from the sheath (designated as L6, L5, L4, L3, L2, and L1), was conducted to study the synergistic regulation mechanism of nitrogen panicle fertilizer on yield, quality, and aroma of Nanjing 9108.【Result】Compared with no nitrogen fertilizer application and no panicle fertilizer application, the application of panicle fertilizer could significantly increase the effective panicle number per unit area and grains per panicle of aromatic japonica rice, thereby enhancing its yield. As the period of panicle fertilizer application was delayed, the yield first increased and then decreased, reaching a maximum at the treatment of applying fertilizer at the fourth leaf from the top (counted downwards from the flag leaf). The application of panicle fertilizer improved rice processing quality, appearance quality, and aroma quality. The period of panicle fertilizer application had an impact on these qualities of aromatic japonica rice. With the delay in the period of panicle fertilizer application, the milled rice rate of Nanjing 9108 showed an increasing trend, but the chalkiness degree increased, leading to a deterioration in appearance quality. Simultaneously, the amylose content decreased while the protein content increased, resulting in a decline in taste value and eating quality. The content of 2-acetyl-1-pyrroline (2-AP), as the main component of aroma, also decreased with the delay in the period of panicle fertilizer application. The application of panicle fertilizer significantly increased the proline content and proline dehydrogenase activity in grains. Advancing the period of panicle fertilizer application had a significant promoting effect on proline accumulation during the rice filling stage, and proline dehydrogenase activity also increased, which was conducive to maintaining higher proline content and proline dehydrogenase activity in grains during the maturity stage, thereby promoting the synthesis of 2-AP in rice grains. Based on a comprehensive evaluation of the effects of panicle fertilizer application period using indicators, such as actual yield, milled rice rate, chalkiness degree, taste value, and grain 2-AP content, it was found that the treatment of applying fertilizer at the fourth leaf from the top had the highest comprehensive score. 【Conclusion】Under the experimental conditions of this study, the application of panicle fertilizer contributed to the synergistic improvement of yield and quality. On the basis of ensuring stable yield, the application of panicle fertilizer at the fourth leaf from the top achieved the best overall benefits in terms of yield, taste, and aroma.

This study aimed to explore an ideal plant type model for high light efficiency rice cultivation in Yunnan Province, thereby promoting rice yields. The experiment utilized low light efficiency rice varieties, namely 'Chujing 27' (HP1), 'Taiwan Upland Rice' (HP2), 'AZUCENA' (HP3), and 'B3619C-7B-8-1-4' (HP4), as well as high light efficiency rice varieties, specifically 'Denong 205' (HP5), 'Dianjingyou 1' (HP6), 'Diantun' 502 (HP7), 'Yunda 107' (HP8), and 'Dianrui 449' (HP9), as experimental materials to investigate rice variety plant type patterns. A single-factor randomized block design was employed, with 9 rice varieties constituting the treatments and 4 replicates per treatment. Rice planting, water, and fertilizer management were conducted according to conventional rice cultivation methods, and relevant agronomic traits for high light efficiency were measured at maturity. The results indicated that the ideal plant type pattern of high light efficiency varieties in Yunnan Province exhibited the following characteristics: a plant height ranging from 90 to 110 cm; a panicle length of 22.0 to 25.3 cm; the number of secondary branches of 25.1 to 31.1; a flag leaf base angle of 10.5 to 17.1°, a flag leaf opening angle of 11.7 to 17.4°, a flag leaf length of 18.7 to 31.1 cm, and a flag leaf width of 1.4 to 1.8 cm. This experiment has elucidated the ideal plant type pattern for high light efficiency rice in Yunnan, thus providing a theoretical foundation for breeding such rice varieties.