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[Objective] The present paper aimed at determining the occurrence of chilli veinal mottle virus (ChiVMV) in tobacco in Guizhou and the genetic evolution relationship between the ChiVMV strains in Guizhou and in other provinces in China, so as to provide a basis for formulating scientific and reasonable prevention and control measures. [Method] 80 tobacco leaf samples suspected of virus infection were collected from the tobacco fields of Guiyang, Zunyi, Anshun and Tongren in Guizhou province, showing the symptoms of leaf mottling, wrinkling, necrosis and mosaic. Multiple viral primers were designed to detect the collected samples by RT-PCR method, and the detected ChiVMV was further amplified by PCR to obtain the whole genome sequence of Guizhou tobacco ChiVMV. Based on all ChiVMV genome sequences published by NCBI, sequence consistency analysis was performed and phylogenetic evolutionary tree was constructed to study the genetic evolutionary relationship of Guizhou ChiVMV tobacco isolates. [Result] The results of RT-PCR showed that the detection rate of ChiVMV was 37. 50%, the detection rate of tobacco mosaic virus (TMV) was 48. 75%, and the detection rate of potato virus Y (PVY) was 35. 00%. The detection rate of cucumber mosaic virus (CMV) was only 8. 75%. Four complex infection types TMV + PVY, PVY + ChiVMV, PVY + CMV and ChiVMV + PVY + TMV were detected, and the detection rates were 26. 25%, 6. 25%, 10. 00% and 3. 75%, respectively. Guizhou tobacco isolate ChiVMV-GZ (GenBank: OP589298) was obtained by PCR. Sequence consistency analysis showed that ChivMV-GZ was identical with tomato isolates from Sichuan (KC711055) and Sichuan tobacco isolates (MK405594) with high sequence consistency (98. 70% and 98. 50%). Phylogenetic tree was constructed and it found that ChivMV-GZ clustered with ChiVMV strains from Sichuan and Yunnan. [Conclusion] The damage of ChiVMV in Guizhou tobacco has been increasingly serious and sufficient attention should be paid. ChiVMV-GZ was isolated from Guizhou tobacco and amplified to obtain the whole genome of the virus in the study. Based on genetic evolution analysis, it was found that ChiVMV-GZ was most closely related to ChiVMV strains from Sichuan and Yunnan. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore the metabolic differences between the local flue-cured tobacco variety Jiucaiping 2 selected by the Bijie Tobacco Company and the control variety Yunyan 87 planted in the Bijie area, lay the foundation for further revealing the molecular mechanism of the aroma style characteristics of Jiucaiping 2 tobacco leaves, and provide theoretical basis for the promotion and application of this variety. [Method]Taking Yunyan 87 as the reference material, the metabolome analysis of Yunyau 87 and Jiucaiping 2 fresh tobacco leaves from three tobacco leaf production areas ( Dayi, Kele, Tiejiaug) in Hezhaug county, Bijie city was carried out by liquid chromatography-mass spectrometry. [ Result] A total of 1880 peaks were detected in the tobacco samples, and principal component analysis showed significant metabolic differences between Jiucaiping 2 and Yunyan 87 in three tobacco producing regions. Metabolite difference analysis was performed with difference multiple greater than 2 and the P < 0. 05 oft-test as the standard. The order of ion quantity differences among different production areas was Dayi > Kele > Tiejiaug. At the same time, it was identified that 46 ion peaks had au increased accumulation in Jiucaiping 2 from three production areas, while 49 ion peaks had a decreased accumulation in Jiucaiping 2 from three production areas. A flavonoid metabolite M_9637[luteolin 7-(6'-malonylglucoside) ]was further identified among the peaks with increased accumulation in Jiucaiping 2. Widely-targeted metabolic analysis of phenolic acids and flavonoids in two tobacco varieties revealed an increasing trend of accumulation of two types of flavonoids (isorhamnetin and quercetin) in Jiucaiping 2. The analysis of nomicotine and nicotine showed that both metabolites tended to accumulate and decrease in Jiucaiping 2. [Conclusion] In the study, the comparative analysis of the metabolites of Jiucaiping 2 and Yunyan 87 in three tobacco producing areas found that the metabolism of flavonoids in Jiucaiping 2 was higher than that of Yunyan 87, and the metabolism of nicotine was lower than that of Yunyau 87. The differences in the accumulation of the above two types of substances may be the basis for the formation of the aroma style characteristics of Jiucaiping 2 tobacco leaves. [ABSTRACT FROM AUTHOR]

[Objective] The purpose of the paper is to explore the impact of biochar on the population structure, diversity and ecological function of fungi in long-term rhizosphere soil and provide insights for improving the microecological environment of tobacco rhizosphere soil and biochar application in tobacco planting soils. [ Method] In the study,' Honghuadajinyuan' tobacco was utilized as the test material. Under the premise of reducing the fertilizer amount by 10%, 250 g/plant ( A1 ), 300 g/plant ( A2) and 350 g/plant ( A3) of bio-carbon fertilizer were applied, with conventional fertilizer used as the control. Illumina MiSeq high-throughput sequencing technology was employed to determine the rhizosphere soil microorganisms of tobacco plants subjected to these different treatments. [ Result] The application of biochar fertilizer had a significant impact on soil c, diversity and population structure, with A3 treatment demonstrating the highest fungal diversity and abundance among all soil samples. At the phylum level, there was a negative correlation between the relative abundance of Ascomycota and the amount of biochar fertilizer applied, while the relative abundance of Basidiomycota exhibited a positive correlation with the quantity of biochar fertilizer application, both of which were the primary dominant bacteria fungi in each treatment. At the genus level, the application of biochar fertilizer led to a significant decrease in the relative abundance of Penicillium, Cladophialophora, and Clonostachys, while significantly increased the relative abundance of Fusarium, Saitozyma, Conocybe. Addtionally, using FUN Guild for fungal function prediction, it was observed that the functional types of rhizosphere soil fungi in each sample were primarily saprophytic and saprophytic-symbiotic. Furthermore, the relative abundance of plant pathogen in soil samples with biochar fertilizer was lower compared to the control group. [ Conclusion] The study shows that the A3 treatment improves the fungal community structure in the rhizosphere soil of tobacco plants, which is more conducive to maintaining the balance of soil ecosystem and restoring soil quality. It can provide technical reference for rational application of biochar fertilizer in tobacco planting areas. [ABSTRACT FROM AUTHOR]

【Objective】 The present paper aimed to optimize the composition of alkaloid in Sichuan cigar and realize the quality improvement and harm reduction of cigar, the conversion degree of nicotine to nornicotine and the distribution of nicotine conversion rate between plants among the main cigar varieties were determined, and variety purification was carried out according to the conversion traits of nicotine.【Method】 Dexue 1, Dexue 3, Dexue 4, Dexue 5, Dexue 7 and Shiyan 1 were used as test materials. The content of alkaloids and TSNAs in the middle leaves of the tested varieties were determined and analyzed. The main cultivars in Sichuan (Dexue 4, Dexue 7 and Shiyan 1) were purified by early conversion stimulation and converter identification. 【Result】 (i) The alkaloid composition and contents in Sichuan cigar varieties were significantly different, and there were different degrees of nicotine conversion in different varieties, and the distribution of nicotine conversion rate between plants was quite different. The nicotine conversion problem of Dexue 5 was prominent. The proportion of converters in the tested group was 100%, and all converters were high converter. There were a large number of nicotine converters in Shiyan 1, among which the low converters were the majority, accounting for 37.9% of the total population. The problems of nicotine conversion in Dexue 1 and Dexue 3 were relatively less serious with all the tested plants being low converters. The conversion rate of Dexue 4 and Dexue 7 were 48% and 30%, respectively. (ii) Based on the early conversion stimulation and converter identification of Dexue 4, Dexue 7 and Shiyan 1, the non-converters were strictly selected for self-fertilize, and the corresponding purified species seeds were obtained. Compared with the corresponding conventional varieties, the nicotine content and nicotine conversion rate of purified variety were significantly reduced, the NNN contents and the total amount of TSNAs were significantly reduced, and the NNN contents of Dexue 7 was reduced from 2615.27 ng/g to 442.67 ng/g, the total amount of TSNAs decreased from 3602.46 ng/g to 1327.24 ng/g, and the NNN contents of Dexue 4 and Shiyan 1 decreased from 3235.76 and 3940.32 ng/g to 945.32 and 1315.40 ng/g, the total amount of TSNAs decreased from 5658.51 and 6669.89 ng/g to 2889.81 and 2840.12 ng/g. The purified variety had better cigar flavor. 【Conclusion】 Sichuan cigar varieties have different degree of nicotine conversion problems. By early conversion stimulation and converter identification and strictly selecting non-converters to self-fertilize for the purification, conversion rate and tobacco-specific nitrosamine contents can be effectively reduced, the quality and safety of cigar can be improved. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to establish a BP (Back propagation) neural network (BPNN) automatic recognition system to achieve the standardization and quantification of flue-cured tobacco browning. 【Method】Taken the upper tobacco leaves of Yunyan 87 as a sample, scanning to obtain characteristic information such as tobacco leaf color, established a BP neural network to identify the degree of browning of flue-cured tobacco, and output the discrimination results, and compared the similarity with the results of artificially discriminating the browning of flue-cured tobacco as a reference. Through the analysis and comparison of appearance quality, conventional chemical composition, polyphenol content, TSNAs content and sensory quality changes, the accuracy of the BP neural network automatic recognition system and manual recognition results were veriofied.【Result】Establishing the BP neural network model could accurately identify tobacco browning level, and its recognition accuracy was 98.75%.There was no significant different among grading tobacco appearance quality, routine chemical compositions, polyphenol content, the content of TSNAs and sensory quality of change and the artificial recognition (P＜0.05).Which provided objective evaluation method for noise smoke, and the availability of tobacco leaves with different browning degrees was effectively distinguished.【Conclusion】The accuracy of the BP neural network recognition system for identifying the degree of tobacco browning is close to that of manual recognition. The BP neural network automatic recognition system can be used to replace manual recognition, which provides a reference for promoting the construction of tobacco BP. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to study the effects of optimized fan frequency and different tobacco density on the temperature difference in the curing barn, changes in tobacco leaves and the quality of cured tobacco, and further determine the applicability of optimized fan frequency in the curing process. 【Method】Two factors of fan frequency and smoke density were set to track the changes of the three smoke density during the process of optimizing the fan frequency and the quality of the cured tobacco during the whole process, and conduct a comparative analysis in combination with the conventional full process of 50 Hz. 【Result】In terms of temperature difference in the roasting barn, as the baking progresses, the temperature difference basically followed the change rule of the main water loss stage>the late stage>the main yellowing stage>the preheating stage, and the optimization of the fan frequency reduces the temperature difference in the roasting barn. In terms of tobacco leaf changes, the unevenness of leaf temperature was D2Y>D1Y>D3Y>D2C; L* value and b* value first increase and then decrease, L* values of D2C and D1Y were always higher than that of D2Y and D3Y; a* value gradually increased with the change of the state, and there was no obvious difference between different treatments; The overall contraction of the optimized fan frequency was good, and the water loss form of D2Y tobacco was the best. In terms of quality of cured tobacco leaves, compared with D2C, D1Y, D2Y and D3Y had significant differences in appearance quality, chemical composition, sensory evaluation and comprehensive score (P<0.05), and D2Y had the highest score. 【Conclusion】Optimizing the fan frequency can have a lower temperature difference in the curing barn under different loading densities, better tobacco leaf changes and higher quality of cured tobacco, which has strong applicability. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to obstain Bacillus mucilaginosus from the rhizosphere soil of Luoyang tobacco plant and improve the content of available free potassium of plants in soil. 【Method】B. mucilaginosus in soil was identified by plate dilution coating, gram staining, physiological and biochemical detection and 16 S rDNA sequence analysis, and the potassium solubility of the strain was compared with that of the standard strain by sodium tetraphenylborate precipitation method. 【Result】Nine single colonies, which were round, white and transparent, with neat edges and smooth protruding, were isolated from the root soil samples of tobacco fields at different growth stages in three counties of Henan province. Which the physiological and biochemical characters of strain 005, 008 and standard strains, were facultative anaerobic bacteria, and hydrogen peroxide enzyme reaction, also can make the starch hydrolysis, sugar alcohol fermentation, nitrate reduction, in the determination of V-P with M. R results have shown positive, in litmus milk test reaction can produce acid reaction, cannot make gelatin liquefaction, which can use citrate. The 16 S rDNA sequences of strain 005（MN227334） and strain 008（MN227337） were 99% homologous to GenBank（EU048557）. It was identified as B. mucilaginosus. The results showed that the precipitation weight of strain 005, 008 and standard strain 23575 was 0. 140, 0. 136 and 0. 166 g, respectively, with a significant difference of 0. 05, which were all 0. 040 g higher than that of the blank group. 【Conclusion】In the rhizosphere soil of Luoyang tobacco plant, there are round, white and transparent facultative anaerobic bacillus coleformis, which can hydrolyze starch, ferment sugar alcohol, reduce nitrate, and have strong ability to release potassium. [ABSTRACT FROM AUTHOR]

【Objective】 The present paper aimed to study the differential expression of male sterility transcriptome-related genes from molecular biology, and to clarify the mechanism of male sterility in tobacco K326. 【Method】 The male sterile line and maintainer line of tobacco K326 at the flowering stage were used as materials, using Illumina Hi Seq high-throughput sequencing technology. Then the corresponding sequence alignment analysis was performed on the sequencing raw data. 【Result】 After filtering the original sequencing data, a total of 84 101 954-134 977 386 clean reads were obtained for comparison and analysis. The base sequencing quality values Q30 were all greater than 94% and the GC content was between 41.84% and 42.50%. In small bud, medium buds and large buds, 7881, 19 931 and 10 984 differentially expressed genes were obtained respectively, of which the down-regulated were significantly more than the up-regulated. These differentially expressed genes were annotated to biological processes, molecular functions and cellular component 3 categories in 35 branches. The highest number of terms for molecular function was at the cellular component level. 1257 differential genes were annotated into the 249 metabolic pathways in the KEGG database. The most significantly enriched pathways in the KEGG metabolic pathways of differential genes were metabolic pathways, secondary metabolite biosynthesis and phenylpropane biosynthesis. Differential genes were analyzed by transcription factor analysis and it was found that the more differential genes belonged to ERF, MYB, C2 H2, NAC, ERKY, bHLH and other transcription factor families in small buds, medium buds and large buds. 【Conclusion】 In the study, we found that there were many differentially expressed genes in MYB transcription factors, metabolic pathways and phenylpropane bio synthesis in about male sterility. Therefore, we suggest that the exploration of tobacco-related male sterility genes and molecular mechanisms be carried out in the aspects of metabolic pathways and phenylpropane biosynthesis in the future. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to provide a reference basis for the safe production in tobacco fields with medium risk of Cd pollution and remediation, the uptake of Cd by tobacco and its distribution pattern in the whole plant were studied. [Method] The tobacco planting soil with medium risk of Cd pollution was selected for pot experiments to explore the remediation potential of 5 tobacco varieties for Cd in the contaminated soil and safety production about of tobacco. [Result] The concentrations of Cd（1.510-2.110 mg/kg) in 5 tobacco varieties were far less than the limit value of Cd（5.0 mg/kg) in Guizhou tobacco leaves. The order of Cd concentration of 5 tobacco varieties was as follows: Guiyan 8 > Yunyan 87 > CF225 > Nanjiang 3 > Bi’na 1.The Cd concerntration of Guiyan 8 was significantly higher than others. There were no significant difference between Bi’na 1 and Nanjiang 3, and they were significantly lower than others. All of 5 tobacco varieties had strong enrichment ability for Cd（127.695%-204.549%), and the order of enrichment ability was as follows: Bi’na 1>Yunyan 87>CF228>Guiyan 8>Nanjiang 3. The accumulation of Cd in Bi’na 1 had 583.102 μg/plant and the remediation efficiency of Cd in soil was 4.113%, more than 4 other tobacco varieties（2.269%-3.262%). The Cd of Bi’na 1 was mainly stored in the unusable parts such as roots, stems and leaf veins in the tobacco. The distribution rate of Cd in leaves of Bi’na 1 was the lowest with 41.03% concentration, which was lower than that of other tobaccos（above 50%). Bi’na 1 reduced the adverse factors（Cd concentration and distribution rate) in the tobacco production. [Conclusion] Among 5 tobacco varieties, Bi’na maximum accumulation amount of Cd, which mainly exists in unusable part, including root, stalk, leave vein, etc. Compared with other four tobacco varieties, Bi’na 1 reduces the disadvantages during tobacco production. Hence, Bi’na 1 has the potential for safe utilization and restoration of tobacco field medium-polluted by Cd. [ABSTRACT FROM AUTHOR]

[Objective]The present paper aimed to optimizating the fertilization technology that is suitable for flue-cured tobacco in Zhaotong tobacco area under the current situation, a 3 -year in situ experiment was conducted. [Method] Different fertilization ratios of field experiments were carried out in 3 consecutive years in Zhaoyang tobacco area by single factor randomized block design. By comparing the agronomic characters, economic characters and leaf quality of flue-cured tobacco under different treatments, the optimal nitrogen application rate and the optimal ratio of nitrogen and phosphorus were determined. [Result] The results showed that with the extension of planting years, the qualities of agronomic traits of flue-cured tobacco decreased, and the occurrence of disease increased. The yield increased slightly, but the proportion of high-quality tobacco leaves, the appearance quality of cured tobacco leaves and the coordination of chemical components of tobacco leaves showed a downward trend. In the comparison of different treatments, the amount of nitrogen application had a certain relationship with the maturity of tobacco leaves. In order to ensure the timely yellowing of tobacco leaves, it was necessary to control the nitrogen application rate. With the increase of nitrogen application rate, the leaf color of tobacco turned from light green to dark green, and the agronomic traits of flue-cured tobacco showed an increasing trend. Under the same nitrogen application rate, the plant height and effective leaf number increased when more phosphorus were applied. The dis ease incidence of non fertilization treatments was higher than that of other treatments, but there was little difference in the disease incidence among fertilization treatments. The coordination between economic characters and tobacco chemical composition in the treatment of 97. 5 and 120 kg/hm² nitrogen application was better than that of the treatment of 75 kg/hm² nitrogen application, and the treatment of 97. 5 kg/hm² nitrogen application showed better performance. Under the same nitrogen application rate, the coordination of economic characters and chemical composition of tobacco leaves in the N/ P ratio of 1: 1. 8 was better than that in the N/ P ratio of 1: 1.2. [Conclusion] In the continuous cropping plots of Zhaotong tobacco area, when the nitrogen application rate is 97. 5 kg/hm², and m (N) : m (P2O5): m (K2O) is 1: 1.8: 3, tobacco leaves can turn yellow in time, and the coordination of agronomic characters, economic characters and chemical components of flue-cured tobacco are good, and good yield and high quality of flue-cured tobacco can be achieved. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to investigate the appropriate amount and tillage effect of straw-rotted organic fertilizer + vertical rotary tillage in tobacco production in Hunan's tobacco-rice rotation, with the aim of improving the soil environment of tobacco planting in Hunan and providing scientific basis for improving the quality and increasing the yield of tobacco. [ Method] The experiment used 7 treatments in randomized group design, Tl: no straw-rotted organic fertilizer + conventional tillage; T2: straw-rotted organic fertilizer 1150 kg/hm² + conventional tillage; T3: straw-rotted organic fertilizer 2300 kg/hm² + conventional tillage; T4: straw-rotted organic fertilizer 4600 kglhm2 + conventional tillage; TS: application of straw-rotted organic fertilizer 1150 kg/hm² + vertical rotary tillage ; T6: application of straw-rotted organic fertilizer 2300 kg!hm2 + vertical rotary tillage; T7: application of straw-rotted organic fertilizer 4600 kg/hm² + vertical rotary tillage. The effects of different treatments on soil nutrients, agronomic traits of tobacco plants, physical traits, appearance quality, chemical composition and economic traits of tobacco leaves after baking were studied by ANOV A and comprehensive evaluation. [ Result] The application of straw-rotted organic fertilizer + vertical rotary tillage significantly increased soil organic matter and fast-acting nutrient content, and the highest soil fertility level was achieved when the straw-rotted organic fertilizer was applied at 4600 kg/hm² . At the same level of organic fertilizer application, the treatment of organic fertilizer + vertical rotary tillage had higher soil nutrients, agronomic properties of tobacco plants, physical properties of post-baking tobacco leaves, appearance quality, chemical composition and economic properties than the treatment of organic fertilizer alone. Among them, the 17 treatment had the highest appearance quality and chemical compatibility scores, with an average increase of 19. 86%, 3. 70% and 11. 53%, 2. 78% compared with Tl and T4. The tobacco yield and production value of 17 treatment increased by 12. 85%, 8. 10% and 26. 84%, 10. 46% compared with Tl and T4. The rate of top quality tobacco increased by 13. 80 and 6. 71 percentage points compared with Tl and T4. [Conclusion ] The application of 4600 kg/hm² straw-rotted organic fertilizer + vertical rotary tillage was the best, and most beneficial to the production of high-quality tobacco in the tobacco-rice rotation area of Hunan. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to study the distributions of heat and humidity environment in the intensive curing period.【Method】The CFD model of the standard bulk curing room was established. The large simulation software Fluent was used to conduct systematic numerical simulation of the temperature, humidity and air distribution inside bulk curing room during the baking and color fixing period, and the validity of the model was verified.【Result】Numerical simulation results showed that under the typical air supply parameters in the color fixing period, the temperature in the upper leaf area was the highest, and that in the lower leaf area was the minimum; In the tobacco stacking area, horizontal temperature gradient increased gradually from top to bottom, and the relative humidity at the air inlet area was the lowest, and at the bottom of the door side was the highest; Temperature and humidity showed uneven distribution on the whole. Based on the numerical simulation results, the distributions of temperature, humidity and air distribution in the smoke chamber under the typical air supply parameters in the color fixing period were analyzed. Considering the reasonable energy consumption of the fan and the wind speed between blades, the wind speed of the inlet should be selected from 3.5-4.2 m/s.【Conclusion】The numerical simulation results can provide reference for the internal structure optimization of bulk curing room and the selection of fan intake during the roasting and color fixing period. [ABSTRACT FROM AUTHOR]

[Objective] The pmpose of this paper is to obtain the basis information of Potyviruses distribution and investigate Potyvirus species between resistant and susceptible tobacco varieties to PVY in field in Yunnan Province. [Method] During 2017 to 2019,497 tobacco samples with typical Potyviral symptoms were collected in 5 cities, 13 tobacco planting counties (districts) in Yunnan Province and the types of Potyviruses on the main susceptible and resistant varieties to PVY were analyzed. [Result] The results showed that 85. 1 % of 497 tobacco samples were infected by Potyviruses in total. Furthermore, the detection rates of TVBMV, ChiVMV, PVY, and TEV were 58. 8 %, 23. 3 %, 14. 9% and 7. 8% respectively. In terms of the rank of detection rates of Potyviruses in the PVY susceptible varieties, the detection rate of TVBMV was the highest in Qujing,and for ChiVMV was in Yuxi,and for PVY was in Zhaotong. The PVY detection rate on the PVY-resistance varieties was 5. 8% around and much lower than that of susceptible varieties (22. 5%). PVY resistant varieties showed a good crop protection for the PVY disease. [ Conclusion] The analysis showed that the resistant varieties which contained va locus dramatically reduced the yield loss in the high incidence areas of PVY, and the increase of TVBMV detection rate in PVY resistant varieties was due to the decrease of PVY incidence rate, and the resistant varieties did not increase the harm of TVBMV and ChiVMV. However, the single va resistant locus had no effect on the TVBMV and ChiVMV. Therefore, the investigation of Potyviruses species should be carried out before introduce va-containing varieties into the area. TVBMV and ChiVMV had been the emerging disease in Yunnan's main tobacco growing areas, resulting in low yield and quality loss. It is necessary to establish new method to detect these causal agents and to screen moreresistant germplasm resources for TVBMV and ChiVMV. [ABSTRACT FROM AUTHOR]