Development of a stable attenuated double-mutant of tobacco mosaic virus for cross-protection

Tobacco(Nicotiana tabacum)and tomato(Solanum lycopersicum)are two major economic crops in China.Tobacco mosaic virus(TMV;genus Tobamovirus)is the most prevalent virus infecting both crops.Currently,some widely cultivated tobacco and tomato cultivars are susceptible to TMV and there is no effective strategy to control this virus.Cross-protection can be a safe and environmentally friendly strategy to prevent viral diseases.However,stable attenuated TMV mutants are scarce.In this study,we found that the substitutions in the replicase p126,arginine at position 196(R^(196))with aspartic acid(D),glutamic acid at position 614(E^(614))with glycine(G),serine at position 643(S^(643))with phenylalanine(F),or D at position 730(D^(730))with S,significantly reduced the virulence and replication of TMV.However,only the mutation of S^(643) to F reduced the RNA silencing suppression activity of TMV p126.A double-mutant TMV-E614G-S643F induced no visible symptom and was genetically stable through six successive passages in tobacco plants.Furthermore,our results showed that TMV-E614G-S643F double-mutant could provide effective protection against the wild-type TMV infection in tobacco and tomato plants.This study reports a promising mild mutant for cross-protection to control TMV in tobacco and tomato plants.

Comparison of Combustion Characteristics of Tars Produced with Tobacco Stem Biomass Gasification

In order to study the combustion characteristics of tar in biomass gasifier inner wall and gasification gas,“tobacco stem semi-tar inside furnace”,“tobacco stem tar inside furnace”and“tobacco stem tar out-of-furnace”were subjected to thermogravimetric experiments,and the combustion characteristics and kinetic characteristics were analyzed.The result shows that“tobacco stem semi-tar inside furnace”has the highest value and“tobacco stem tar out-of-furnace”is has the lowest value on ignition characteristics,combustion characteristics and combustible stability;“tobacco stem semi-tar inside furnace”has the lowest value and“tobacco stem tar outside furnace”has the highest value on burnout characteristics;“tobacco stem tar outside furnace”has the highest value and“tobacco stem tar inside furnace”has the lowest value on integrated combustion characteristics.

Plant Chemical Defenses against Insect Herbivores—Using theWild Tobacco as a Model

The Nicotiana genus, commonly known as tobacco, holds significant importance as a crucial economic crop. Confrontedwith an abundance of herbivorous insects that pose a substantial threat to yield, tobacco has developed adiverse and sophisticated array of mechanisms, establishing itself as a model of plant ecological defense. Thisreview provides a concise overview of the current understanding of tobacco’s defense strategies against herbivores.Direct defenses, exemplified by its well-known tactic of secreting the alkaloid nicotine, serve as a potent toxinagainst a broad spectrum of herbivorous pests. Moreover, in response to herbivore attacks, tobacco enhancesthe discharge of volatile compounds, harnessing an indirect strategy that attracts the predators of the herbivores.The delicate balance between defense and growth leads to the initiation of most defense strategies only after aherbivore attack. Among plant hormones, notably jasmonic acid (JA), play central roles in coordinating thesedefense processes. JA signaling interacts with other plant hormone signaling pathways to facilitate the extensivetranscriptional and metabolic adjustments in plants following herbivore assault. By shedding light on these ecologicaldefense strategies, this review emphasizes not only tobacco’s remarkable adaptability in its natural habitatbut also offers insights beneficial for enhancing the resilience of current crops.

Variations of phyllosphere microorganisms in asymptomatic and tobacco brown spot leaves before and after spraying 12% difenoconazole + fluxapyroxad SC

12%difenoconazole+fluxapyroxad SC(commercial name:Jiangong)was first released by BASF in China in 2016.It has been registered to control many diseases,including pear scab,apple Alternaria leaf spot,tomato early blight,cucumber powdery mildew,etc.This study evaluated the bioactivity of Jiangong against Alternaria alternata and explored variations of phyllosphere microorganisms in both asymptomatic and tobacco brown spot leaves at different persistence periods(0,5,10,and 15 days post-fungicide application)using high-throughput sequencing technology.The results indicated that Jiangong effectively inhibited mycelial growth(average EC_(50) value of 0.51μg/mL),conidia germination(average EC_(50) value of 3.47μg/mL),and the carbon metabolism of A.alternata.Both asymptomatic and symptomatic leaves presented complex microbial communities.Higher fungal diversity was noted in asymptomatic leaves,while higher bacterial diversity was found in symptomatic leaves.After application,the diversity and abundance of microbial community structures in both types of leaves changed over time.Fungal microbiome communities showed greater sensitivity than bacterial groups,with the microbiome communities of asymptomatic leaves being more affected than those of symptomatic leaves.Fungal community diversity decreased for both symptomatic and asymptomatic leaves after 5 days of application,while the diversity of fungal community in symptomatic leaves showed an upward trend after 10 days of application.Meanwhile,bacterial community diversity increased in both symptomatic and asymptomatic leaves after 5 days of application but then declined in asymptomatic leaves after 15 days.The abundance of the dominant function group of phyllosphere bacteria(metabolism,genetic information processing,environmental information processing)was not affected by the application of Jiangong.However,the abundance of the dominant function group of phyllosphere fungi(animal pathogen-endophyte-wood saprotroph,endophyte-plant pathogen,plant pathogen-undefined saprotroph)was significantly affected by the application of Jiangong,and high variation was found in symptomatic leaves than that of asymptomatic leaves.The application of Jiangong-induced alterations in the community structure of the tobacco phyllosphere microbiome provides a basis for future tobacco brown spot control strategies based on phyllospheric microecology.

Smokeless Tobacco Use among Women in Kasama District-Zambia

Background: Smokeless tobacco is defined as a product that contains tobacco, is not smoked or burned at the time of use, and commonly consumed orally or nasally. These products can be placed in the mouth, cheek or the lip and are sucked or chewed. The Zambian government, in the 2019 country report, gave an estimated figure of 4.5% of females aged 15 years and above in 2017 used smokeless tobacco and by 31st December, 2018, there was an increase of smokeless tobacco users to 6.8% women of the same age group. This study aimed to explore the extent of smokeless tobacco use among women in Kasama district-Zambia. Methodology: An analytical cross-sectional quantitative study design was used to collect data using the modified structured interview schedule, adopted from Medicine for Global Health. Simple random sampling method using rotary technique was used to select 430 respondents after meeting the inclusion criteria. Informed consent to participate in the study was obtained. Data was analysed using version 26.0 of the Statistical Package for Social Sciences. Appropriate parametric or non-parametric statistical tests (Chi-squared or Fisher’s exact test) were adopted in testing for associations between variables. Univariable and multivariable binary logistic regression analysis were employed in identifying smokeless tobacco use among women using an investigator-led stepwise approach, guided by various fit statistics and the likelihood ratio test. All statistical analyses adopted a 5% significance level at 95% confidence interval. Results: The results showed that most of the respondents were aged between 18 and 25 years (45.6%), (53.7%) lived in urban settlements and the majority (80%) were unemployed. The majority of respondents (83.5%) had a friend/relative who used smokeless tobacco and over half (53.5%) thought smokeless tobacco was beneficial to them. The commonly mentioned benefits of smokeless tobacco included body warmth (13.6%) and vaginal tightening (7.9%). The results revealed that most of the respondents attained a secondary level of education (38.4%). According to the study, smokeless tobacco use among women of Kasama-Zambia was significantly associated with the following;age (p Conclusion: Based on these findings, the study recommends that efforts should be channeled towards the dissemination of information on the impacts of smokeless tobacco use in order to overcome cultural beliefs attached to smokeless tobacco use.

Determinants of Tobacco Cultivation and the Associated Impacts of Adoption in Hurungwe District, Zimbabwe

Tobacco is an essential cash crop in Zimbabwe and a strategic livelihood option for hundreds of thousands of rural households. However, the crop is linked to negative environmental, economic, and social impacts. The existing studies on tobacco cultivation in Zimbabwe present contradictory findings on the determinants and impacts of adoption, leaving unanswered questions about the crop’s sustainability impact in the country. This article investigates the determinants of smallholder farmers’ decisions to grow tobacco and the associated impacts of adoption. Random and purposive sampling were used to select 273 household surveys, including tobacco and non-tobacco smallholder farmers, and 56 expert interviews to answer the research questions. We employed regression models alongside expert interviews and document analysis to identify the determinants influencing the decision-making process of smallholder farmers in Zimbabwe regarding tobacco cultivation. Additionally, our investigation aimed to elucidate the perceived impacts associated with the adoption of this agricultural practice. The regression analysis indicated that the farmer’s age, education level, farming experience, family size, household income, and perceived high farm profitability are significant drivers of tobacco adoption. We also discovered divergent and convergent perceptions of the critical impacts of tobacco cultivation. The study highlights the need for proactive multi-stakeholder collaboration and sustainable financial arrangements to address the negative impacts of tobacco production. As the primary stakeholder responsible for regulating and promoting agricultural activities, the Zimbabwean government should provide meaningful financial support, increase access to credit, and ensure better market facilities for alternative crops to reduce the over-dependence on tobacco.

Field Prevention and Control of Tobacco Black Shank in Guizhou Province

[Objectives]The paper was to explore the prevention and therapeutic schedule of tobacco black shank.[Methods]Different concentrations of 25 g/L fludioxonil·37.5 g/L metalaxyl-M,10 billion/mL Bacillus amyloliquefaciens,110 g/L amino acids·24 g/L manganese zinc,120 g/L calcium·20 g/L magnesium,and 4%metalaxyl-M·64%mancozeb were employed to assess their efficacy in controlling tobacco black shank.The disease index was subsequently evaluated.[Results]25 g/L fludioxonil·37.5 g/L metalaxyl-M+10 billion/mL B.amyloliquefaciens+110 g/L amino acids·24 g/L manganese zinc(transplanting dosage)or 120 g/L calcium·20 g/L magnesium(sealing dosage)(transplanting dosage:750 mL/hm 2+1.2×104 mL/hm 2+1.5×103 mL/hm 2,sealing dosage:1.5×103 mL/hm 2+1.2×104 mL/hm 2+1.5×103 mL/hm 2)resulted in a notable impact on the prevention of tobacco black shank.The incidence in the treated area was 10.78%,a 35.72%reduction compared to the control.The estimated yield was 99700 yuan/hm 2,a 34.91%increase compared to the control.25 g/L fludioxonil·37.5 g/L metalaxyl-M+10 billion/mL B.amyloliquefaciens+120 g/L calcium·20 g/L magnesium+4%metalaxyl-M·64%mancozeb(control dosage:1.5×103 mL/hm 2+1.2×104 mL/hm 2+1.5×103 mL/hm 2+1.5×103 g/hm 2,1.5×103 mL/hm 2+1.2×104 mL/hm 2+1.5×103 mL/hm 2+1.5×103 g/hm 2,with an interval of 7 d between applications)demonstrated a significant efficacy in controlling tobacco black shank.At 7 d following the second application,the relative preventive efficacy was observed to be 88.99%.Additionally,the estimated yield was 109900 yuan/hm 2,representing an increase of 244.51%compared to the control.[Conclusions]During the transplanting and sealing stages,25 g/L fludioxonil·37.5 g/L metalaxyl-M+10 billion/mL B.amyloliquefaciens+110 g/L amino acids·24 g/L manganese zinc(transplanting dosage)or 120 g/L calcium·20 g/L magnesium(sealing dosage)may be employed to enhance the growth of tobacco plants and mitigate the occurrence of tobacco black shank.Additionally,25 g/L fludioxonil·37.5 g/L metalaxyl-M+10 billion/mL B.amyloliquefaciens+120 g/L calcium·20 g/L magnesium+4%metalaxyl-M·64%mancozeb can be utilized for the treatment of tobacco black shank during the initial incidence stage.

Association of cannabis use disorder with atrial fibrillation in young men without concomitant tobacco use:Insights from nationwide propensity matched analysis

BACKGROUND Recent data are inconclusive regarding the risk of arrhythmias among young cannabis users.Furthermore,many young adults use both cannabis and tobacco,which could add a residual confounding effect on outcomes.So,we studied young men who have cannabis use disorder(CUD)excluding tobacco use disorder(TUD)to understand their independent association with atrial fibrillation(AF)and related outcomes.AIM To study the association of CUD with AF and related outcomes.METHODS We used weighted discharge records from National Inpatient Sample(2019)to assess the baseline characteristics and mortality rates for AF-related hospitalizations in young(18-44 years)men in 1:1 propensity-matched CUD+vs CUD-cohorts without TUD.RESULTS Propensity matched CUD+and CUD-cohorts consisted of 108495 young men in each arm.Our analysis showed an increased incidence of AF in black population with CUD.In addition,the CUD+cohort had lower rates of hyperlipidemia(6.4%vs 6.9%),hypertension(5.3%vs 6.3%),obesity(9.1%vs 10.9%),alcohol abuse(15.5%vs 16.9%),but had higher rates of anxiety(24.3%vs 18.4%)and chronic obstructive pulmonary disease(COPD)(9.8%vs 9.4%)compared to CUD-cohort.After adjustment with covariates including other substance abuse,a non-significant association was found between CUD+cohort and AF related hospitalizations(odd ratio:1.27,95%confidence interval:0.91-1.78,P=0.15).CONCLUSION Among hospitalized young men,the CUD+cohort had a higher prevalence of anxiety and COPD,and slightly higher proportion of black patients.Although there were higher odds of AF hospitalizations in CUD+cohort without TUD,the association was statistically non-significant.The subgroup analysis showed higher rates of AF in black patients.Large-scale prospective studies are required to evaluate long-term effects of CUD on AF risk and prognosis without TUD and concomitant substance abuse.

Correlation Analysis between Well-cellar Early Transplanting of Robust Seedlings and Diseases in Shiyan Tobacco-growing Area

[Objectives]The paper was to investigate the relationship between the well-cellar early transplanting of robust seedlings and the prevalence of diseases in the Shiyan tobacco-growing area.[Methods]The relationship between disease occurrence and meteorological factors during the field growth period was examined by analyzing the prevalence of flue-cured tobacco virus diseases,brown spot,and total disease in the Shiyan tobacco-growing area before(2013-2017)and after(2018-2022)the well-cellar early transplanting of robust tobacco seedlings.[Results]The implementation of a well-cellar early transplanting technique of robust seedlings resulted in a reduction in the average incidence of tobacco virus disease,brown spot,and total disease by 0.83%,8.85%,and 7.91%,respectively,in comparison to the incidence observed prior to early transplanting.These findings suggest that early transplanting can significantly reduce the incidence of flue-cured tobacco diseases.Prior to the well-cellar early transplanting of robust tobacco seedlings,there was a significant(including highly significant)positive correlation between the incidence of brown spot and total disease and precipitation in August and September.The incidence of brown spot and total disease in tobacco plants was found to be significantly positively correlated with May precipitation and significantly negatively correlated with May sunshine hours following the well-cellar early transplanting of robust seedlings.The advancement of the transplanting period by 20 d resulted in a reduction in the growing period of tobacco plants in the field under autumn rains(late August to November)in western China.This effectively circumvented the suitable conditions for disease occurrence and can reduce the incidence of disease.[Conclusions]This study offers a framework for enhancing the quality and efficiency of flue-cured tobacco production in the northwest tobacco-growing area of Hubei.

Green manuring facilitates bacterial community dispersal across different compartments of subsequent tobacco

Green manure–crop rotation is a sustainable approach to protect crops against diseases and improve yield.However,the mechanism by which green manuring manipulates the crop-associated microbial community remains to be elucidated.In this study,we explored the horizontal processes of bacterial communities in different compartments of the soil–root interface(bulk soil,rhizosphere soil,rhizoplane and endosphere)of tobacco by performing a field experiment including four rotation practices,namely,tobacco rotated with smooth vetch,ryegrass,radish,and winter fallow(without green manure).Results showed that the co-occurrence networks constructed by adjacent compartments of the soil–root interface with green manuring had more edges than without green manuring,indicating dramatic microbial interactions.Green manuring increased the dispersal-niche continuum index between bulk soil and other compartments,indicating that it facilitated the horizontal dispersal of microbes.For the different green manuring practices,the neutral community model explained 24.6–27.6%of detection frequency for bacteria,and at least one compartment under each practice had a normalized stochasticity ratio higher than the 50%boundary point,suggesting that the deterministic and stochastic processes jointly shaped the tobacco microbiome.In conclusion,green manuring generally facilitates bacterial community dispersal across different compartments and enhances potential interactions among adjacent compartments.This study provides empirical evidence for understanding the microbiome assembly under green manure–crop rotation.

Evaluation of Protector 700 Wd in Controlling Tobacco Pests in Tanzania

In Tanzania, tobacco is an important cash crop benefiting most farmers and stakeholders. However, the crop is characterized by a low yield per unit area. Several factors are responsible for the low yield and quality of tobacco, among which are damages caused by the insects and other pests. Major insect pests of tobacco are cutworms (Agrotis spp), budworms (Heliothis virescens (F.)), (Lepidoptera Noctuidae) and aphids (Myzus persicae, Aphis tabaci) (Homoptera: Aphididae). These pests adversely affect crop growth, yield and leaf quality. In order to reduce insect attack in tobacco, applying pesticides is a critical management practices. In Tanzania, various pesticides have been approved for use in controlling the pests. Currently, farmers are using Bamethrine 2.5 EC to control the pests. The Pesticide named Protector 700 WG with an active ingredient imidacloprid 700 g/kg is a new product introduced in Tanzania during the 2021/22 crop season. Research trials were conducted in three research sites, namely Ulowa-Kahama, Tumbi-Tabora and Mtanila-Chunya, on Protector 700 WG efficacy in different rates, 15 g, 20 g, and 25 g each dissolved in 20 litres of water. The Protector 700 Wg was compared with the standard pesticide (Bamethrin 2.5 EC). Absolute control was also inclusive where the plot had no application of pesticides. The results showed that Protector 700 WG at all rates outweigh the commonly used pesticide. The difference in the number of pests between Protector 700 WG and Bamethrin 2.5 EC was significantly at P < 0.005 also, in dry and green weights, the yield was significantly different at P < 0.005. However, when yield and number of insects were compared among the rates of protector, there was no significant difference. From these results, farmers are advised applying Protector 700 WG at the rate of 0.15 kg/ha by dissolving it in 200 litres of water.

Does higher tax rate affect tobacco usage?Unravelling the nexus between tobacco regulatory control and public health concern

Objectives:Bangladesh stands as a prominent global consumer of tobacco,with alarming consequences on public health.The Global Adult Tobacco Survey reported that tobacco consumption claimed over 126000 lives in 2018,contributing to 13.5%of all deaths in the country.This study aims to explore the effectiveness of higher tax rates and tobacco use regulation as control mechanisms in mitigating tobacco consumption and health care cost burden,with a particular emphasis on its implications for public health.Methods:This study is based on the annual time series data over the period 2000-2020.The study employs the ordinary least square method to analyze the quantitative confirming the stationarity of data at level.This research uses different models to investigate individual effects and combined effects on both tobacco consumption and tobacco health care cost burden.Results:The study finds a negative relationship between tobacco tax rate and tobacco consumption.More specifically,the higher tax rate of tobacco(low(β=-0.3495),medium(β=-0.2319),high(β=-0.9033),premium(β=-0.7322),filtered(β=-0.2114),and non-filtered(β=-0.3452)categories)is significant to reduce tobacco use at 1%level of significance.The study finds similar results when it applied tobacco retail price instead of tobacco tax rate as the independent variable.Finally,the study investigates the impact on health care cost through tobacco consumption,tobacco control law,growth rate,export-import,and tobacco production.The results indicate that tobacco consumption,export-import,and tobacco production increases health care cost burden while tobacco use regulatory decreases it.By reducing tobacco consumption,higher taxes and tobacco use regulation contribute to alleviating the burden on the healthcare system,promoting healthier lifestyles,and aligning with global health objectives.Conclusions:Higher tax rate on tobacco products is necessary to increase the retail price so that tobacco users cannot consume tobacco.Specific tax and uniform tax base are needed so that tobacco users cannot switch to lower priced brands.Tobacco control laws need to revised and proper implementation should be ensured as well,to achieve the goal of tobacco free Bangladesh by 2040.Tobacco-related diseases,responsible for a significant proportion of deaths in the country,could witness a considerable decline with the successful implementation of higher tax rates and tobacco use regulation.This study provides insights that not only contribute to the economic discourse but also accentuate the broader public health benefits arising from effective tobacco taxation policies.

Effects of Microbial Fertilizers in Improving Acidic Tobacco-planting Soil and Tobacco Leaf Quality

[Objectives]This study was conducted to improve acidic soil and enhance the quality of tobacco leaves.[Methods]The effects of different microbial fertilizers on improving acidic tobacco-planting soil and tobacco leaf quality were investigated through plot experiments.[Results]The application of microbial fertilizers could improve the pH value of acidic soil,and composite microbial agent A showed the best application effect.The application of bio-organic fertilizer was beneficial to improving the contents of available phosphorus and available boron in acidic soil.The application of composite microbial agent A was beneficial to improving the contents of available phosphorus and available potassium in acidic soil,and could promote the growth of tobacco plants and improve the economic traits of flue-cured tobacco and the coordination of chemical components in tobacco leaves.The application of composite microbial agent B led to a downward trend in the content of available boron in acidic soil.The application of composite microbial agent B could promote the absorption of nutrients by tobacco plants,and improve their disease resistance and the quality of tobacco leaves.Due to the differences in functional microorganisms contained,the application effects of different microbial fertilizers in improving acidic tobacco-planting soil and improving tobacco leaf quality varied.Overall,the application of microbial fertilizers could increase soil pH,activate soil nutrients,promote tobacco growth,enhance disease resistance,increase tobacco output value,and improve tobacco quality.Microbial fertilizers have good application prospects in improving acidic soil and improving tobacco quality.[Conclusions]The application of microbial fertilizers to improve acidic tobacco-planting soil can ensure the normal growth and development of tobacco plants and the improvement of tobacco leaf quality,achieving high-quality and sustainable development of Zhaotong tobacco.

Study on the Cultivation Problems and Strategies for New Professional Tobacco Farmers in China

At present,there are still many difficulties in China s tobacco farmers,such as unreasonable age structure,generally low education level,lack of management ability,and low planting efficiency.It is necessary to cultivate new professional tobacco farmers.Based on the practical problems existing in the cultivation of professional tobacco farmers in China,such as vague screening criteria,lack of pertinence in training content,single training mode,immature evaluation system,insufficient follow-up support and unsystematic cultivation mechanism,this study put forward corresponding strategies and suggestions.

Aluminum Toxicity:A Case Study on Tobacco(Nicotiana tabacum L.)

Aluminum is an abundant metal in the earth’s crust that turns out to be toxic in acidic environments.Many plants are affected by the presence of aluminum at the whole plant level,at the organ level,and at the cellular level.Tobacco as a cash crop(Nicotiana tabacum L.)is a widely cultivated plant worldwide and is also a good model organism for research.Although there are many articles on Al-phytotoxicity in the literature,reviews on a single species that are economically and scientifically important are limited.In this article,we not only provide the biology associated with tobacco Al-toxicity,but also some essential information regarding the effects of this metal on other plant species(even animals).This review provides information on aluminum localization and uptake process by different staining techniques,as well as the effects of its toxicity at different compartment levels and the physiological consequences derived from them.In addition,molecular studies in recent years have reported specific responses to Al toxicity,such as overexpression of various protective proteins.Besides,this review discusses data on various organelle-based responses,cell death,and other mechanisms,data on tobacco plants and other kingdoms relevant to these studies.

Effects of Different Chemical Fertilizer Reduction Techniques on Flue-cured Tobacco Production

[Objectives]This study was conducted to find out the most suitable special formula fertilizer for flue-cured tobacco production in tobacco-growing areas of Zhaotong City,so as to provide a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.[Methods]Different formulas of special base fertilizer and special topdressing for tobacco were designed by optimizing and adjusting the application amounts and proportions of nitrogen,phosphorus,potassium and medium trace elements in fertilizer formulas,and the formulas of special base fertilizer and special topdressing for flue-cured tobacco production were selected through a field plot experiment.[Results]The combination of special base fertilizer and special topdressing was conducive to the early growth and rapid growth of tobacco plants under the condition of reduced fertilizer application,and the treatment using organic-inorganic compound fertilizer as the special base fertilizer was the most obvious,with an average growth period of two days increased.Compared with conventional fertilization,the yield,output value,average price,proportion of superior tobacco and proportion of medium and superior tobacco increased in the organic-inorganic compound fertilizer treatment,with the yield increasing by 5.96%,the output value increasing by 17.08%,the average price increasing by 10.49%,the proportion of superior tobacco increasing by 4.63%,and the proportion of medium and superior tobacco increasing by 2.44%.It was concluded from indexes including growth period,agronomic traits,disease incidence and economic traits,the fertilization mode of organic-inorganic compound fertilizer with the addition of trace elements(boron,magnesium and zinc)applied as the base fertilizer and nitrogen and potassium topdressing was most efficient and economic.[Conclusions]This study provides a basis for scientific fertilization and reduced application of inorganic fertilizers with improved efficiency in tobacco production in Zhaotong City.

Effects of Tillage Depth on Nutrients and Microbial Communities in Tobacco-Planting Soil

The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.

Control Effect of UAV Low Volume Spray Technology on Thrips and Tomato Spotted Wilt Virus in Tobacco Field

[Objectives]The paper was to explore the influence of unmanned aerial vehicle(UAV)low volume spray technology on the control effect of viruliferous thrips and tomato spotted wilt virus(TSWV)under different pesticide concentrations,and to explore the effective control nodes and methods of thrips and TSWV.[Methods]According to the occurrence characteristics of thrips and TSWV,the field control effects of 4 pesticides on thrips and TSWV were tested by UAV with the thrips number and disease index as indicators,following the principle of regional and periodic control trials.[Results]In the groups of UAV and artificial prevention and control,4 agents were used alternatively,including 1%emamectin benzoate ME,1.7%abamectin imidacloprid ME,5%emamectin benzoate WDG,and 30%pyriproxyfen dinotefuran SL.There was no significant difference in the control effect of thrips and TSWV among treatment 1(recommended dosage of UAV agent),treatment 2(reduction of recommended dosage of UAV agent by 25%)and treatment 4(recommended dosage of artificial control agent),and the control effects on thrips were more than 83.16%in the 3 treatments.The disease index of TSWV in the 3 treatments decreased from 8.64±1.37 in the blank control group to less than 3,which reached the prevention and control threshold.But treatment 3(reduction of recommended dosage of UAV agent by 50%)did not reach the prevention and control threshold.The disease index of TSWV in the blank control area increased with the increase of the number of live nymphs of thrips,and there was a significant positive correlation,with good fitness.[Conclusions]UAV has a significant impact on the control effect of thrips and TSWV under different pesticide concentrations.In the actual flight control application,it is recommended that the amount of the pesticides is about 3/4 and not less than 1/2 of that of the artificial application.The control area should be extended to 100 m of the ridge of the tobacco field,and UAV is used periodically to control thrips and TSWV for 5 times from pre-transplanting stage to pre-squaring stage of flue-cured tobacco.The control effect is significantly different from the traditional artificial application.

不同基因型烤烟对镰刀菌根腐病的抗性鉴定与评价

为明确不同基因型烤烟对烟草镰刀菌根腐病的抗性,利用10个烟草品种(系),采用粗毒素幼芽接种、带菌菌谷接种、孢子悬浮液培养等方法进行抗性鉴定。结果表明,供试品种对尖孢镰刀菌抗性表现出显著差异;对尖孢镰刀菌表现出抗的品种(系)有4个,分别是‘Y2001’、‘Y2002’、‘长脖黄’、‘664-01’;对尖孢镰刀菌表现出感的品种(系)有6个,分别是‘7710’‘、7713’‘、Y2007’‘、Y2008’‘、中烟100’、‘小黄金1025’。3种接种方法鉴定结果基本一致,共筛选出4个抗性品种(系)。

Age Structure and Change Trend of Tobacco Farmers:A Case Study of Shashi Town,Liuyang City,Hunan Province

Taking the tobacco-growing area of Shashi Town,Liuyang City as the object,the number of registered,newly added and resigned tobacco farmers in each year,average age,number and proportion of tobacco farmers of different ages,number and proportion of tobacco farmers born in different eras,as well as planting scale and planting history of flue-cured tobacco in the last 10 years were analyzed statistically.The results showed that the number of tobacco farmers in Shashi Town showed a rapid decline trend from 2012 to 2018,while the average age continuously increased,and the average planting scale rose in a wave like way.From 2019 to 2021,the decline rate of the number of tobacco farmers slowed down,and the average planting scale continuously increased,while the aging of tobacco farmers accelerated.Meantime,the birth years of tobacco farmers were further concentrated in the 1960s,and they were mainly at the age of 50-59.The tobacco industry in Shashi Town of Liuyang City is facing the crisis of aging tobacco farmers and no successor of flue-cured tobacco planting,and it is predicted that the next 5-10 years will continue the change trend from 2019 to 2021.