Current issue

• 2024 Vol.40 No.27 Published:25 September 2024

  Effects of Water and Straw Treatment on Seedling Quality and Yield of Maize ZHAO Ailian, FAN Heqin, YANG Yulong, WEN Tao, LIU Tianxue, ZHAO Xia, YUE Yanjun 2024, 40 (27):  1-6.  DOI: 10.11924/j.issn.1000-6850.casb2022-1019 Abstract + ( 131 )   HTML ( 4 )   PDF ( 1183KB )   ( 39 ) In order to mitigate the adverse effects of drought on the development of summer maize seedlings caused by climate change, using ‘Zhengdan 958’ as experimental material, the effects of different treatment combinations on soil moisture and growth of maize seedling were studied. The results showed that the soil moisture content increased with the depth of the soil layer, and the pattern was moist soil, wheat straw returning to the field>normal moisture content, wheat straw returning to the field>moist soil, wheat straw not returning to the field>dry soil, wheat straw returning to the field>normal moisture content, wheat straw not returning to the field>dry soil, wheat straw not returning to the field. SPAD value, photosynthetic rate and yield showed the same trend, normal moisture content, wheat straw returning to the field>moist soil, wheat straw returning to the field>moist soil, wheat straw not returning to the field>normal moisture content, wheat straw not returning to the field>dry soil, wheat straw returning to the field>dry soil, wheat straw not returning to the field. Therefore, compared with the removal of stubble, plain stubble can better improve the soil water environment, increase the emergence rate and photosynthetic rate of maize, and increase the yield, which can be widely applied in production.

  Effects on Dry Matter Accumulation and Transport and Yield of Spring Maize: Nitrogen and Phosphorus Double Removal and Reduction under Shallow Buried Drip Irrigation WANG Zhenzhen, ZHANG Yuqin, YANG Hengshan, ZHANG Ruifu, JIN Yu, WANG Shuxuan, LU Minyuan 2024, 40 (27):  7-13.  DOI: 10.11924/j.issn.1000-6850.casb2023-0838 Abstract + ( 91 )   HTML ( 3 )   PDF ( 1176KB )   ( 29 ) To investigate the effects of nitrogen and phosphorus double removal and reduction on yield, dry matter accumulation and translocation of spring maize under shallow buried drip irrigation, the four treatments of N2P2 nitrogen and phosphorus constant, N2P2 nitrogen fertilizer 30% reduction, N2P2 phosphorus fertilizer 30% reduction and N2P2 nitrogen and phosphorus both 30% reduction were set up to determine the SPAD value, leaf area index, dry matter accumulation and yield of spring maize using conventional fertilization as the control. The results showed that compared with CK, yield of N2P2 increased by 4.71% and 3.84% in 2019 and 2020, and the leaf SPAD value, leaf area index increased, dry matter accumulation and translocation contribution to kernel and yield all increased significantly. Under the nitrogen and phosphorus double removal, constant fertilizer application increased the dry matter accumulation and improved the dry matter transport to grain; the dry matter accumulation, translocation contribution to seed grain and yield all decreased under 30% reduction of phosphorus and nitrogen fertilizer; the yields of 2019 and 2020 respectively decreased by 3.22% and 3.84% under 30% reduction of phosphorus fertilizer at the N1 level, and the yields of 2019 and 2020 respectively decreased by 8.23% and 16.35% under 30% reduction of nitrogen fertilizer at the P1 level.

  Effects of Sowing Date, Density and Fertilizer Levels on Agronomic Traits and Yield of Soybean in Soybean and Maize Composite Planting LI Yanlan, YANG Jincheng, WANG Xianzhi, LI Zaofu, LI Xiaoliang, GAO Shilan, LI Wenjun, LIU Jianjian, HU Xinzhou, CAI Shujiang, LI Xiang, LUO Bin 2024, 40 (27):  14-19.  DOI: 10.11924/j.issn.1000-6850.casb2024-0022 Abstract + ( 111 )   HTML ( 3 )   PDF ( 1104KB )   ( 22 ) To screen the best cultivation measures for soybean-maize intercropping, the effects of sowing date, density and fertilizer application rate on main traits and yield of soybean were studied by three-factor and three-level orthogonal test. The results showed that choosing fresh corn and soybean compound planting enabled soybeans to have a long photoperiod after corn harvest; increasing plant height, number of nodes in the main stem, number of effective pods per plant, number of grains per plant, 100-grain weight, and grain weight per plant had a facilitating effect on soybean yield, while the number of grains per plant, grain weight per plant, and hundred-grain weight had a decisive effect on the yield. Condensation analysis showed that cultivation with sowing period from April 30 to May 10, density of 210000-240000 plants/hm2, and fertilizer application rate of 300-375 kg/hm2 could obtain higher yield.

  Effects of Nitrogen Application Position on Growth, Nitrogen Accumulation and Yield of Peanut SONG Jian, WANG Jie, SI Tong 2024, 40 (27):  20-26.  DOI: 10.11924/j.issn.1000-6850.casb2024-0042 Abstract + ( 113 )   HTML ( 7 )   PDF ( 1195KB )   ( 189 ) This study, through simulation of field experiment, investigated the effects of nitrogen application in podding layer and root zone on peanut growth, nitrogen accumulation, and grain yield by applying nitrogen at the flower bud stage under the same nitrogen input conditions. The results showed that the application of fertilizer at the podding layer significantly increased the plant height and the length of the first pair of lateral branches by more than 12% and 9% compared with the control treatment, during the podding stage. Compared with the control, fertilization in both podding layer and root zone increased the total number of peanut needles, with the podding layer treatment showing a significant increase of 5.97% in total peanut needles compared to the root zone treatment in 2022. In the pod maturity stage, the plant height with podding layer fertilization was significantly increased by more than 10% compared to the control. Compared with the control, both podding layer and root zone fertilization improved the length of the first pair of lateral branches and the total number of peanut needles. The dry matter accumulation and nitrogen accumulation in roots, stems, leaves, fruiting needles and pods in the podding layer and root zone fertilization treatments were significantly higher than those in control treatment. Compared with the control group, the single pod weight, the number of pods per plant, the number of mature pods and the pod weight per hundred in the podding layer fertilization treatment were generally increased by more than 20%. The single pod weight and the number of pods per plant in the podding layer fertilization were significantly higher by more than 15% compared to the root zone fertilization. In conclusion, this study proved that applying nitrogen fertilizer at the podding layer was beneficial to the growth, nitrogen accumulation and yield improvement of peanuts.

  Effects of Controlling Water to Promote Root and Sparse Sowing to Breed Long-Leaf Age Strong Root Seedlings on Accumulation of Dry Matter and Nitrogen, Phosphorus and Potassium in Flue-Cured Tobacco XIAO Zhipeng, LI Jianhua, WANG Weimin, WEN Weikang, JIANG Zhimin, XU Zhiqiang, MU Tingting, ZENG Huiyu, AN Ran, HUANG Qionghui, DENG Yongsheng, DENG Xiaohua 2024, 40 (27):  27-39.  DOI: 10.11924/j.issn.1000-6850.casb2024-0048 Abstract + ( 89 )   HTML ( 3 )   PDF ( 1277KB )   ( 98 ) To explore the effects of cultivating strong root seedlings by controlling water to promote root and sparse sowing to breed long-leaf age seedling on tobacco dry matter and nitrogen, phosphorus and potassium accumulation, two factors of controlling water to promote root and raising long-leaf tobacco seedlings by sparse sowing were designed by using 'Yunyan 87' as material. The dry matter, N, P, K accumulation and distribution, and N, P, K fertilizer utilization efficiency of flue-cured tobacco in the rosette stage, topping stage and round top stage were analyzed, and the η2 value was used to evaluate the contribution rate of controlling water to promote root and sparse sowing to breed long-aged strong root seedlings and their interaction. The results showed that increasing the aperture of nursery site, adding microbial agents in the substrate, moisture management adopted by floating seedling at early seedling stage and wet seedling at late seedling stage could improve the dry matter accumulation of tobacco plant, the dry matter distribution of tobacco leaf, the accumulation of N, P and K, the dry matter accumulation efficiency of flue-cured tobacco, the leaf production efficiency, and promote the fertilizer absorption. The contribution rates of controlling water to promote root, sparse sowing to breed long-aged and their interaction on dry matter accumulation of flue-cured tobacco were 30.42%, 51.71% and 17.87%, and those of nitrogen accumulation in flue-cured tobacco were 24.44%, 47.72% and 27.84%, respectively. The contribution rates of phosphorus accumulation in flue-cured tobacco were 25.69%, 45.66% and 28.65%, and those of potassium accumulation in flue-cured tobacco were 30.00%, 44.03% and 25.97%, respectively. Therefore, in the rainy paddy-tobacco growing area of the south, the ways of controlling water to promote root could replace the two-stage seedling cultivation and cultivate strong seedlings with long suitable planting period, which was beneficial to promote early growth and rapid development of flue-cured tobacco and lay the foundation for high quality and high yield.

  Regeneration System of Codonopsis pilosula Resources: Seed Sterilization Methods WANG Qiubao, MA Hongbin, WANG Yaoqin, TIAN Hongling, LIU Yuexian, PEI Shuaishuai, ZUO Xianqiang 2024, 40 (27):  40-45.  DOI: 10.11924/j.issn.1000-6850.casb2023-0822 Abstract + ( 100 )   HTML ( 1 )   PDF ( 1284KB )   ( 23 ) As an authentic medicinal material in Shanxi Province, Codonopsis pilosula (Franch.) Nannf. is well-known throughout the country for its quality and curative effect. In order to effectively protect the high-quality germplasm resources of Codonopsis pilosula, an efficient regeneration system of Codonopsis pilosula was constructed. In this experiment, Codonopsis pilosula seeds were used as test materials, using 4 different treatment methods, after isolation and wrapping, two different sterilizers were used to treat mercury and sodium hypochlorite, respectively, and the damage to the seeds by different treatments was observed to determine the best sterilization method.The results showed that under different sterilization treatments, the seed contamination rate was 0-92.7%, and the survival rate was 0.8%-91.3%. Based on the combination of pollution rate and survival rate, treatment 29 was selected as the best result and followed by treatments 30. After wrapping the seeds in method 4, the best effect was achieved after 60-120 s of mercury sterilization, and the survival rate of the seeds was 82.00%-91.3%, while the contamination rate was 2.17%-3.83%. This experiment establishes a seed sterilization method suitable for the regeneration system of Codonopsis pilosula and lays the foundation for biotechnological breeding of Codonopsis pilosula.

  Effect of Sowing Density and Depth on Emergence and Yield of Machine-sowed Spinach SUN Zhaofa, ZHANG Gongchen, JIANG Zhixun, DUAN Yujun, LIU Qianqian 2024, 40 (27):  46-51.  DOI: 10.11924/j.issn.1000-6850.casb2024-0037 Abstract + ( 143 )   HTML ( 3 )   PDF ( 1054KB )   ( 31 ) In order to find out the suitable sowing density and depth for spinach production, four spinach varieties with significant differences in hundred grain weight and germination rate were used to study the effects of mechanical sowing density and depth on spinach germination and yield. The results showed that when the hundred grain weight of spinach was less than 1.0 g and the germination rate was high, an ideal sowing density could be achieved by using a 5 mm diameter sowing wheel. A sowing wheel with a diameter of 6 mm needed to be used for the seeds with low germination rate. When the hundred grain weight was over 1.8 g, a 7 mm diameter sowing wheel was required to achieve the ideal sowing density. The germination time of spinach was delayed as the sowing depth increasing from 1.5 cm to 3 cm, resulted in the number of sprouts and yield decrease. The number of sprouts and yield were highest at the sowing depth of 1.5 cm. Therefore, the ideal sowing depth is 1.5 cm. In order to get an ideal density, we should use suitable sowing wheel according to the seed size. The difference between theoretical and practical emergence rate varies with seed size and sowing depth, and requires further research.

  Research Progress on Spatio-Temporal Characteristics and Driving Factors of Water Footprint for Rice Production in China MENG Qinghao, RU Yan, ZHANG Ying, WANG Chen, WEN Ya, FA Xiaotong, ZHANG Hao 2024, 40 (27):  52-59.  DOI: 10.11924/j.issn.1000-6850.casb2023-0902 Abstract + ( 87 )   HTML ( 3 )   PDF ( 1170KB )   ( 948 ) Rice is the most water-intensive crop in China, and water footprint for rice production as a measure of the total water consumption of a crop in a certain range of time and space, can measure the water resources in rice production accurately. In this paper, the temporal and spatial characteristics of water footprint for rice production were summarized, and the driving factors behind the temporal and spatial characteristics of water footprint for rice production were analyzed. The existing problems and the prospect of future research were put forward.

  Spectral and Thermogravimetric Analysis of Soil Humic Substances Under Different Cultivation Conditions SONG Ge, XU Zhiqiang, SUN Jingsi, ZHAO Xuening 2024, 40 (27):  60-68.  DOI: 10.11924/j.issn.1000-6850.casb2024-0061 Abstract + ( 80 )   HTML ( 2 )   PDF ( 2223KB )   ( 86 ) Soil humic substance (HS) was extracted from different soil types with sodium pyrophosphate (Na4P2O7) solution and its spectral and thermogravimetric characteristics were studied. The effects of reclamation on the chemical composition and molecular structure characteristics of HS were studied by scanning electron microscopy, UV-visible diffuse reflectance spectroscopy, infrared spectroscopy and thermogravimetric analysis. The results showed that the appearance of HS was uneven, and the surface was irregular with some fine particles and large specific surface area. The influence of reclamation on the appearance of black soil HS was relatively small, while on gray soil HS was relatively large. Due to the complexity of HS chemical composition and the interaction of its functional groups, no obvious characteristic absorption peak was observed in UV-Vis diffuse reflectance spectrum. UV characteristic parameters showed that the values of SUV254 and E4/E6 was inconsistent, suggesting that multiple methods were required to study the chemical composition and structural characteristics of soilHS. The infrared spectroscopy results indicated that HS from uncultivated gray soil (AY+AEL), cultivated gray soil (PY1), and cultivated black soil (PU1) contained high contents of phenols, carboxylic acids, oxygen-containing functional groups, aliphatic and aromatic structures. Reclamation had different impacts on black soil and gray soil. After reclamation, the contents of phenolic compounds, carboxylic acids, hydroxyl groups, quinones, aliphatic and aromatic compounds in black soil HS increased, but the contents of aliphatic compounds and alkanes in gray soil HS decreased. Thermogravimetric analysis indicated that reclamation increased the content of aliphatic structure in black soil HS, but decreased the contents of aliphatic and aromatic structure in gray soil HS, which was basically consistent with the results of infrared spectroscopy. The impact of reclamation on black soil was relatively small, while on gray soil was relatively large. Under reclamation conditions, black soil organic carbon was not easy to lost, which to some extent promoted the accumulation of soil organic matter. On the other hand, organic carbon in gray soil was oxidized and decomposed into compounds with relatively simple structures under reclamation. This study provided a theoretical basis for research on HS biochemistry, and development and utilization of soil resources rationally.

  Effect of Amendments on High Concentration Lead-contaminated Soil in Guangxi ZENG Weiquan, GUO Dajie, YUAN Hui 2024, 40 (27):  69-74.  DOI: 10.11924/j.issn.1000-6850.casb2023-0892 Abstract + ( 95 )   HTML ( 2 )   PDF ( 1063KB )   ( 15 ) In order to reduce the harm of high lead-contaminated soil to crops, three additives of superphosphate, organic fertilizer and phosphorus rock powder were used to explore the remediation effect on high lead- contaminated soil in Guangxi through pot experiments. The results showed that compared with the control group T0, the application of superphosphate, organic fertilizer and phosphorus rock powder significantly reduced the harm of lead poisoning (P < 0.05) to different degrees, reduced soil pH and soil DTPA-Pb, water soluble Pb content, improved the survival rate and biological yield of pakchoi, and reduced the enrichment coefficient of lead in pakchoi. The above amendments can be used as the preferred improvement materials for high lead-contaminated soil in Guangxi.

  Effects of Long-term Non-grain Production on Soil Physicochemical Properties of Topsoil in Ningbo Area YING Hong, ZHU Shijun, JIN Shuquan, WANG Feng, ZHOU Jinbo 2024, 40 (27):  75-82.  DOI: 10.11924/j.issn.1000-6850.casb2024-0006 Abstract + ( 95 )   HTML ( 2 )   PDF ( 1633KB )   ( 22 ) To provide a reference for the restoration and utilization of non-grain cultivated land, the effects of long-term non-grain production on soil physicochemical properties of topsoil in Ningbo area were explored deeply. In this study, soil samples were collected from 130 non-grain cultivated land and 53 control plots, and then were systematically analyzed based on geomorphic types (water network plain, coastal plain, hilly area and valley plain) and non-grain planting types (nursery land and orchard). The results showed that: the pH, organic matter content and soil bulk density of non-grain cultivated land were 5.74±0.83, 24.72±8.01 g/kg and 1.28±0.05 g/cm3, respectively, significantly lower or higher than that of surrounding paddy fields (6.17±1.02, 30.07±10.68 g/kg and 1.18±0.05 g/cm3, respectively)(P<0.05). Under different terrains, the effects of non-grain production on soil physicochemical properties were different, and the greater effects were found in hilly areas and valley plains. Specifically, there was a decrease of more than 10% in EC, organic matter and total nitrogen content, and pH value decreased into an acidic level less than pH 5.5. The two non-grain production types of nursery stock and orchard both led to the decrease of pH, EC, CEC, organic matter and total nitrogen content and the increase of soil bulk density, and the former had a greater impact. The organic matter content of nursery stock was 22.90±7.18 g/kg, significantly lower than that of orchard and control plots (30.07±10.68 g/kg and 26.87±8.44 g/kg)(P<0.05). Our results indicated that the long-term non-grain production in Ningbo resulted in soil acidification, decreased fertility and increased soil compactness, and the restoration and utilization of non-grain cultivated land should fully consider the differences of geomorphic types and non-grain planting types.

  Effect of Dry and Wet Alternation on Change of Potassium Effective Form in Tobacco-planting Soil LIANG Hui, CHEN Yunsong, LI Jie, CHEN Yulan, HUANG Rong, WANG Changquan, LI Bing 2024, 40 (27):  83-89.  DOI: 10.11924/j.issn.1000-6850.casb2024-0023 Abstract + ( 89 )   HTML ( 3 )   PDF ( 2141KB )   ( 122 ) The aims were to study the effects of water conditions on the potassium availability, to clarify the response of soil potassium available to dry or wet alternation and provide scientific basis for accurate understanding of the potassium supply in tobacco planting soil and rational application of potassium fertilizer. Two ecological regions, Huidong (humid monsoon climate zone) and Dechang (plateau monsoon climate zone), were selected as the main types of tobacco soil (purple soil and red soil). Soil samples were collected in different layers (0-20, 20-40 and 40-60 cm), and different moisture conditions (constant humidity, alternating dry and wet, wet) were set up in culture experiment. The effects of dry and wet alternation on the content of available potassium, effective potassium and slowly available potassium in soil were studied. The results showed that constant water, dry and wet alternation, and wet treatments increased the available potassium content in each soil layer of purple soil (Huidong county) and red soil (Huidong county, Dechang county), with the maximum increase value of 85.96 mg/kg, and decreased the available potassium content of purple soil in Dechang county. Soil slow available potassium content showed an opposite trend to that in available potassium content. The effective potassium content of purple soil and red soil in Huidong area increased with the culture time along, but the change of effective potassium content in purple soil and red soil in Dechang area was opposite. Water condition and clay mineral type might be the important factors affecting the change of potassium available form in Dechang purple soil and red soil. In the production of flue-cured tobacco, it was necessary to pay attention to the supply of appropriate potassium fertilizer to purple soil in Dechang area especially in rainy season.

  Impact of Straw Returning Combined with Fertilizer Application on Soil Nutrients and Agronomic Traits and Yield of Highland Barley LI Shimeng, YUAN Yuting, NAN Zhiqiang, WANG Jinxiong 2024, 40 (27):  90-96.  DOI: 10.11924/j.issn.1000-6850.casb2024-0029 Abstract + ( 85 )   HTML ( 2 )   PDF ( 1061KB )   ( 45 ) The study aimed to investigate the effects of combining rapeseed straw returning and chemical fertilizer application on soil nutrient composition, agronomic traits and yield of highland barley in Tibet, to provide a scientific basis for the efficient utilization of rapeseed straw resources as fertilizer in this region. Field experiments were conducted using the cultivar ‘Zangqing 3000’. Four levels of fertilization were applied (urea and diammonium phosphate at rates of 0, 60, 120 and 180 kg/hm2, and 0, 75, 150 and 225 kg/hm2, respectively), alongside four levels of rapeseed straw returning (0, 1500, 3000 and 6000 kg/hm2). The results showed that rapeseed straw returning predominantly influenced the total phosphorus and organic matter content in the topsoil, while the fertilization primarily affected total nitrogen and phosphorus content, with no significant effect on other soil nutrients. In terms of agronomic traits such as basic seedling number, plant height, effective panicle number and yield of highland barley, there were significant differences between different fertilization levels. At the same time, there were also significant differences in basic seedling number and yield between different straw retuning treatments. The integration of straw returning and chemical fertilizer application was found to enhance barley yield compared to the exclusive use of chemical fertilizers. The maximum barley yield was achieved with a straw returning of 6000 kg/hm2 (full returning) and application of urea and diammonium phosphate at 180 and 225 kg/hm2, respectively, resulting in a 4.03% yield increase compared to the yield without straw returning at equivalent fertilization levels. In conclusion, in Tibet, rapeseed straw returning combined with chemical fertilizer application can not only enhances soil nutrient, but also significantly increase the yield of highland barley.

  Study on Abundance and Deficiency of Medium and Trace Elements in Key Tea Gardens in Hangzhou YUAN Hangjie, WANG Jingwen, YANG Wenye, LI Dan 2024, 40 (27):  97-101.  DOI: 10.11924/j.issn.1000-6850.casb2024-0049 Abstract + ( 83 )   HTML ( 2 )   PDF ( 1063KB )   ( 46 ) To find out the abundance and deficiency of available medium and trace elements in tea gardens in Hangzhou, 30 representative topsoil samples from eight major tea-growing counties were collected and analyzed. The results showed that available iron and zinc were abundant overall, but large areas of available copper and part areas of available manganese, boron, sulfur, calcium and magnesium were deficient. The contents of medium and trace elements in soil varied greatly among tea plantations. The spatial variation of available copper, iron, boron and sulfur elements was moderate, while the variation of available manganese, zinc, calcium and magnesium elements was strong. Available copper, iron, zinc, boron and sulfur in soil were negatively correlated with pH, while available manganese, calcium and magnesium were positively correlated with pH. Available iron, manganese, zinc, boron, calcium and magnesium in soil were positively correlated with organic matter, while available copper and sulfur were negatively correlated with organic matter. There were both symbiosis and mutual inhibition between medium and trace elements. Therefore, according to the conditions of medium and trace elements in the soil of different tea gardens, the corresponding micro-fertilizer should be applied according to local conditions in addition to increasing the application of organic fertilizer to prevent excessive acidification of soil in tea gardens.

  Identification and Evaluation of Field Resistance to Rice Blast in Japonica Rice Cultivars CHEN Jianchen, DONG Liying, LIU Pei, TANG Cuifeng, SONG Jie, XIANG Jinqian, LIU Shufang, YU Lei, YANG Qinzhong 2024, 40 (27):  102-107.  DOI: 10.11924/j.issn.1000-6850.casb2024-0054 Abstract + ( 93 )   HTML ( 3 )   PDF ( 1150KB )   ( 496 ) In order to compare the differences of resistance to rice blast disease in Yunnan among japonica rice cultivars collected from 17 provinces, and to screen favorable resistant resources of rice, we employed the method of natural induction in field blast nursery to assess the resistance of 1050 japonica rice cultivars against leaf and panicle blast. The results indicated that among the 1050 japonica rice cultivars, there was lighter incidence of leaf blast and more severe incidence of panicle blast. Regarding leaf blast resistance, the cultivars exhibiting high resistance, resistance, moderate resistance, moderate susceptibility, susceptibility, and high susceptibility accounted for 28.48%, 10.95%, 9.14%, 19.24%, 20.00%, and 12.19%, respectively. As for panicle blast resistance, the cultivars exhibiting high resistance, resistance, moderate resistance, moderate susceptibility, susceptibility, and high susceptibility accounted for 3.71%, 0.38%, 2.57%, 19.62%, 22.57%, and 51.14%, respectively. Further analysis of the leaf and panicle blast results revealed that 69 japonica rice cultivars had resistance to both leaf and panicle blast. These 69 cultivars were collected from five provinces of Jilin, Heilongjiang, Liaoning, Yunnan, and Jiangsu. These results suggested that these cultivars with good resistance against both leaf and panicle blast in blast nursery could be served as important resistance resources for blast disease-resistant rice breeding, and discovery of new genes conferring resistance to rice blast.

  Relationships Between Population Densities of Meloidogyne graminicola and Yield Loss of Upland Rice XIAO Qingyan, ZHANG Lu, YANG Zhuhong, PENG Deliang, YE Shan, DING Zhong 2024, 40 (27):  108-114.  DOI: 10.11924/j.issn.1000-6850.casb2023-0909 Abstract + ( 86 )   HTML ( 2 )   PDF ( 1249KB )   ( 172 ) To determine the relationship between population density of Meloidogyne graminicola and yield loss in upland rice, the effects of Meloidogyne graminicola initial population density (Pi) on the yield of upland rice and reproduction of nematodes were evaluated in pot experiments under the screen house condition with dry planting and management. The results revealed a linear regression relationship where rice parameters such as root length, root weight, plant height, tiller number, panicle length, 1000-seed weight and single basin grain weight decreased as Pi increased. The yield loss ranged from 28.4% at a Pi of 2 eggs and J2/100 cm3 soil to 67.8% at a Pi of 200 eggs and J2/100 cm3 soil. The reproduction factor of nematodes followed a declining trend with Pi. The relationship between population density and relative yield followed the Seinhorst model, Y=0.24+0.76(0.3252)(Pi). A significant positive correlation was noted between upland rice yield loss and Pi of 2 to 200 eggs and J2/100 cm3 soil under dry planting and management, indicating a high risk of harm to upland rice caused by M. graminicola.

  Effect of Density on Survival of Hippodamia variegata Larva YONG Yanping, XU Bingyan, LIU Hongling, LI Yang, HE Hengguo, PU Deqiang 2024, 40 (27):  115-120.  DOI: 10.11924/j.issn.1000-6850.casb2024-0070 Abstract + ( 86 )   HTML ( 2 )   PDF ( 1191KB )   ( 244 ) In order to clarify the effects of feeding density on the development period, pupa rate, adult rate and weight of Hippodamia variegata, as well as to explore efficient feeding techniques for this species, four groups of early-stage larvae were subjected to different feeding densities (A: 100 heads/box, B: 200 heads/box, C: 300 heads/box, D: 400 heads/box, the volume of the breeding box is 1000 mL). The molting, pupa, eclosion time and the number of pupation and eclosion adults of each age of H. variegata were observed and counted. The results showed that the development duration of larvae and pupa of H. variegata in groups A, B, C, and D were (11.75±0.65) days, (12.06±0.77) days, (12.45±0.60) days, and (12.70±0.21) days, respectively. The number of pupation was (85.25±4.87), (147.50±3.12), (193.75±21.40) and (156.25±29.62), of which (49.00±6.68), (74.25±12.06), (107.75±16.76) and (103.75±15.78) pupae could be collected. The number of eclosion adults was (75.25±6.73) heads, (123.75±8.05) heads, (160.25±27.22) heads and (110.75±26.68) heads, respectively. The weight of adults was (7.39±0.13) mg/head, (7.32±0.29) mg/head, (7.29±0.20) mg/head and (6.56±0.12) mg/head, respectively, and the number of abnormal adults was (5.25±1.65) heads, (12.75±4.33) heads, (19.50±5.24) heads, (10.50±3.90) heads, respectively. With the increase of feeding density, the development period of H. variegata was gradually prolonged, the number of pupation, eclosion and deformity was gradually increased, and the pupation rate, eclosion rate and adult weight gradually decreased. In conclusion, the instar larvae of H. variegata had a feeding density of 300 heads/box, and the number of pupation and eclosion adults was large, and the weight was normal, which was the optimal feeding density.

  Effects of Exogenous Selenium on Rice Growth and Survival of Sogatella furcifera (Hemiptera: Delphacidae) ZHENG Jinyan, SUN Qianyang, ZHANG Ning, LIU Feng, HAN Yongqiang 2024, 40 (27):  121-125.  DOI: 10.11924/j.issn.1000-6850.casb2024-0071 Abstract + ( 81 )   HTML ( 2 )   PDF ( 1203KB )   ( 253 ) To explore the effects of exogenous selenium (Se) on rice growth and survival of Sogatella furcifera feeding on Se-treated rice plants, a susceptible cultivar 'Taichung Native 1' (TN1) was served as the test rice variety. Six Se concentrations of 10, 20, 30, 40, 50 and 60 μmol/L were set up by adding sodium selenite (Na2SeO3) to the nutrient solution, and 0 μmol/L was used as the control to determine the effects of different concentrations of Se on rice growth and the survival of S. furcifera feeding on Se-treated rice plants. The results indicated that the plant height, root length, fresh weight and dry weight per plant treated with 10 μmol/L Se were significantly higher than that of control; while the plant height, root length, fresh weight and dry weight per plant treated with 20-60 μmol/L Se were lower than that of control. Se content in rice plants were increased significantly with the increase of Se concentration in nutrient solution, while survival rate of S. furcifera were decreased significantly with the increase of Se content in rice plants. The survival rate of S. furcifera fedding on rice plants treated with 10 μmol/L Se decreased significantly on the 4th to 7th day after the treatment. In conclusion, 10 μmol/L is the appropriate concentration of Se, which can promote rice growth and reduce the survival rate of S. furcifera.

  Prediction Model of Sensory Quality of Cigar Raw Materials Based on BP Neural Network HOU Bingqing, WANG Shuoli, ZHANG Youjie, CAO Yang, SHI Xiangdong, DING Songshuang, LIU Bingyang, WANG Yihui 2024, 40 (27):  126-133.  DOI: 10.11924/j.issn.1000-6850.casb2024-0036 Abstract + ( 94 )   HTML ( 4 )   PDF ( 1631KB )   ( 52 ) By establishing BP neural network model, the relationship between conventional chemical components and sensory quality of cigar raw materials was explored, in order to predict sensory quality of cigar raw materials quickly and accurately. With the content of conventional chemical components in cigar leaves from Sichuan, Hubei, Yunnan, Hunan and Nicaragua as input variables and the sensory quality indexes of cigar raw materials as output variables, BP neural network models with topological structure of 6-9-1 were constructed respectively to predict the sensory quality evaluation results of cigar raw materials. The results showed that in the samples tested, the contents of total sugar, reducing sugar, nicotine and chlorine in cigar leaves from four major producing areas in China were higher than those of Nicaraguan tobacco leaves. Nicaraguan tobacco leaves scored higher in aroma quality and volume of aroma, Sichuan tobacco leaves scored lower in irritation, Hubei cigar leaves scored higher in aftertaste, Yunnan tobacco leaves scored lower in impurity, and Hunan tobacco leaves scored higher in combustibility and gray. In this study, the statistical characteristics of conventional chemical components and sensory quality indexes of cigar tobacco samples were good, basically following normal distribution. The difference between the predicted value and the actual value of the BP neural network model was small, among which the correlation coefficients of aftertaste, irritation, gray and total score were all above 0.9. Among the errors of the predicted and actual values of the training set, verification set and test set, except the error interval of the total score was large, the error interval of the remaining most indexes was more than 85% within the range of 0-0.5. The prediction model of the sensory quality of cigar materials established by BP neural network has a good fitting effect, which can be used to predict the sensory quality of cigar materials based on conventional chemical components, and promote the innovative development of Chinese cigar.

  Quality Analysis of Sichuan Dark Tea and Construction of Flavor Wheel LIU Xiao, TANG Xiaobo, XIONG Yuanyuan, MA Weiwei, WANG Xiaoping, WANG Yun, LI Chunhua, QIU Xingfen, ZHANG Ting 2024, 40 (27):  134-143.  DOI: 10.11924/j.issn.1000-6850.casb2024-0038 Abstract + ( 85 )   HTML ( 4 )   PDF ( 1287KB )   ( 27 ) To analyze the current quality status of Sichuan dark tea and provide data basis for improving the quality of Sichuan dark tea, 48 representative dark tea samples from Sichuan Province were selected as the survey subjects, and their sensory qualities and physicochemical components (tea polyphenols, amino acids, water extracts, caffeine, catechins, and tea pigments) were analyzed. The taste and aroma flavor wheels were plotted. The quality characteristics of Sichuan dark tea are mainly characterized by "strong" and "mellow". Its quality components include water extract content of 20.73%-44.93%, tea polyphenol content of 2.99%-15.94%, free amino acid content of 0.21% -1.83%, caffeine content of 1.13%-4.34%, tea polysaccharide content of 0.80%-3.19%, theoflavin content of 0.05%-0.29%, thearubigin content of 0.14%-4.98%, theabrownin content of 3.39%-14.35%, and total catechin content of 0.23%-9.85%. Principal component analysis shows that the main representative indicators of Sichuan dark tea are polyphenols, caffeine, and tea polysaccharides; when the critical value is 10, 48 samples are divided into 3 categories through cluster analysis. The flavor wheel indicates that the aroma types of Sichuan dark tea include aged aroma, sweet aroma, glutinous aroma, etc. The taste types include "strong", "mellow", "sweet", "thick", and "smooth", but a certain proportion of products have quality defects such as "sour", "burnt", "bitter", and "astringent". The overall quality of Sichuan dark tea is good, but the aroma of Sichuan dark tea products is not diverse enough. Therefore, it is recommended to strengthen independent breeding and moderate introduction of tea tree varieties with woody and medicinal aroma, and carry out targeted research on stacking technology that adapts to the characteristics of different regions based on the main varieties planted in Sichuan.

  Analysis of Flavor Substances of Cigar Tobacco Under Different Fermentation Conditions: A Review ZHOU Quanwei, LIU Lulu, YANG Zhen, JIANG Zhongrong, ZHANG Jiabao, SHI Xiangdong, LI Dongliang 2024, 40 (27):  144-151.  DOI: 10.11924/j.issn.1000-6850.casb2024-0033 Abstract + ( 104 )   HTML ( 3 )   PDF ( 1375KB )   ( 2263 ) The flavor substances of cigar tobacco leaves play a decisive role in the stylistic characteristics of cigars. Fermentation is an important process to improve the quality of cigar tobacco, which can affect the type, content and composition ratio of flavor substances in cigar tobacco, thus determining the quality of cigar tobacco leaves and cigar tobacco quality. This paper reviews the mechanism of fermentation and flavor perception of cigar tobacco leaves and the progress of flavor analysis of cigar tobacco leaves under different fermentation conditions, summarizes their effects on cigar tobacco leaves, and looks forward to the future research on cigar flavors to provide theoretical support for related research.

  Overwintering Culture Experiment of Leiocassis longirostris in Greenhouse Ponds LIU Yongshi, XU Jiabo, SHI Yonghai, LIU Jianzhong, JIA Chuipan, WANG Jianjun 2024, 40 (27):  152-158.  DOI: 10.11924/j.issn.1000-6850.casb2024-0041 Abstract + ( 107 )   HTML ( 4 )   PDF ( 1166KB )   ( 22 ) To provide a feasible technical scheme for the overwintering Leiocassis longirostris culture in the Yangtze River Delta, the feeding and growth of the Leiocassis longirostris under the overwintering culture mode were studied. The overwintering rearing technology and the growth characteristics of 0+ age young fish and 1+ age fish Leiocassis longirostris under greenhouse pond condition in 2021—2022 and 2022—2023 were explored and investigated in this study. The initial body length and mass of 0+ age young fish Leiocassis longirostris were 14.78 cm and 40.83 g, with the stocking density of 83340 tails/hm2 (3402.60 kg/hm2). The initial body length and mass of 1+ age fish Leiocassis longirostris were 21.99 cm and 156.86 g, with the stocking density of 42525 tails/hm2 (6670.20 kg/hm2). The results showed that the water temperature could be kept above 11℃ and 10℃ under the greenhouse pond condition. During the pre-winter breeding period (December to the end of February), the feeding of Leiocassis longirostris was relatively stable. Since March, with the increase of water temperature, the daily feeding amount rapidly increased. The cumulative feeding amount during the overwintering period was 4009.00 kg/hm2 and 4715.00 kg/hm2, respectively. After 150-152 d of rearing, the growth rate of 0+ age young fish and 1+ age fish Leiocassis longirostris were 23.7% and 10.2%, weight gain rates were 131.8% and 51.7%, specific growth rates for body length were 0.140%/d and 0.065%/d, specific growth rates for body mass were 0.553%/d and 0.278%/d, daily growth rates were 0.023 cm/d and 0.015 cm/d, and daily mass gain rates were 0.354 g/d and 0.541 g/d, respectively. The condition factors of 0+ age young fish and 1+ age fish Leiocassis longirostris at harvest time were 1.52 and 1.62, the survival rates were 92.8% and 99.7%, the yield per unit area was 7317.00 kg/hm2 and 10093.65 kg/hm2, and feed coefficients were 1.02 and 1.38, respectively. In conclusion, the water temperature can be kept above 10℃ under greenhouse pond condition, Leiocassis longirostris may maintain continuous feeding and exhibit good growth performance. This study provides technical support and theoretical basis for the facility culture of Leiocassis longirostris in the Yangtze River Delta region.

  Study on Relationship Between Odor Material Geosmin and Environmental Factors in Aquaculture Ponds ZHONG Liqiang, ZHOU Liying, ZHANG Shiyong, LIU Hongyan, CHEN Xiaohui, WANG Minghua 2024, 40 (27):  159-164.  DOI: 10.11924/j.issn.1000-6850.casb2024-0114 Abstract + ( 92 )   HTML ( 2 )   PDF ( 1175KB )   ( 10 ) This study aims to analyze one of the main obstacles in the consumption and processing of freshwater fish products - the earthy smell, especially its key odorant compound geosmin (GSM). By testing the GSM concentration in 84 aquaculture ponds in Jiangsu Province and their water environmental factors (including salinity, pH, dissolved oxygen, temperature, total suspended solids, total nitrogen, total phosphorus, and permanganate index), correlation analysis and path analysis methods were used to screen out the key environmental factors affectingGSM. The results show that the detection rate of GSM in all ponds is as high as 97.6%, with an average detected content of (27.83±20.06) ng/L, which largely exceeds the human perception threshold; salinity and permanganate index have a significant negative impact on GSM, and the direct effects of both salinity and permanganate index are greater than their indirect effects, with these two factors independently playing a negative regulatory role in the GSM of aquaculture ponds. Therefore, in the process of aquaculture management, salinity and permanganate index can be taken as the key environmental factors for monitoring the water environment of aquaculture ponds, targeted management measures can be adopted accordingly, thereby improving the water quality of aquaculture ponds and more effectively and conveniently solving the problem of earthy smell in aquaculture water bodies and products.