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【Objective】To conduct a comprehensive evaluation of the flue curing characteristics of flue-cured tobacco, classify the flue curing characteristics and screen the accessing traits of flue curing characteristics. 【Method】 This study adopts six varieties of flue-cured tobacco which includes K326, Yueyan 97, Yanyan 97, Huayan 12, Huayan 06 and Shaoyan 1 as the experimental materials. It, under the southern three-stage flue curing process, uses Correlation Analysis, Principal Component analysis and Stepwise Regression Analysis to investigate the agronomic traits, physiological and biochemical indexes and yield and quality indexes related to the flue curing characteristics. 【Result】There is a highly significant positive correlation between the curing coefficients and the ratio of free water to bound water, the average rate of chlorophyll degradation, the rate of chlorophyll degradation in the first 48 hours and the rate of carotenoids degradation in the first 48 hours.A significant positive correlation exists between the flue curing index and fresh water content and fresh dry ratio of fresh tobacco leaves. 【Conclusion】The average rate of chlorophyll degradation and the rate of carotenoids degradation in the first 48 hours are effective indexes to evaluate the curing characteristics of tobacco leaves, besides, the ratio of free water to bound water could be used as a reference index to evaluate the flue curing characteristics of tobacco leaves. [ABSTRACT FROM AUTHOR]

[Objective] To explore the inhibitory effect of hiocontrol strain JT86 on sclerotia-producing pathogens of tobacco. [Methods] The cell wall hydrolase activities in the fementation broth of Pseudomonas aeruginosa 186 were detected using the double-antibody sandwich method. The mycelium and sclerotia morphological changes of the pathogen treated with JT86 fermentation broth were observed using scanning electron microscopy. The inhibitory effects on the hyphal growth and clematia germination of Rhizoctonia solani, Sclerotium ralf, and Sclerotinia sclerotiarum were tested. [Results] The inhibitory rates of JT86 fermentation broth on the hyphal growth of R. salani 5. rolfsii and S. sclerotiaru w 77.07% 50.82% and 95.25% respectively. After 24 h treatment with JT86 fermentation broth, the sclerotia of the three pathogens did not germinate, with inhibitory rates all reached 100% JT86 fermentation houth had high protease, cellulase and chitinase activities, but did not produce indoleacetic acid. Scanning electron microscopy showed that JT86 fermentation broth could cause severe hyphal atrophy and deformity of R. zolani. [Conclusion] The JT86 fermentation both had good inhibitory effects on the growth and development, as well as selestial germination of R. solani, S. ralfiii and S. scleratiorum. [ABSTRACT FROM AUTHOR]

Good soil conditions lead to the formation of tobacco yield and quality and the sustainable development of land use. The research progress of planting methods, fertilization and soil conservation and improvement in flue-cured tobacco production on soil conditions and tobacco production in China in recent years was reviewed. The regulation effects of agronomic measures on soil physical, chemical and microbial performance were systematically discussed, and suggestions were put forward for the improvement and conservation of soil conditions for tobacco planting to provide reference for guiding the regulation of tobacco production in the fi [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore suitable water and fertilizer integration with reduced fertilization mode for flue-cured tobacco production on slope land in southern tobacco-growing areas [Method] Taking the local conventional water and fertilizer management as a comparison, the effects of water and fertilizer integration on dry matter accumulation, N and K absorption and distribution, fertilizer utilization rate and soil nutrient balance of Hue-cured tobacco on slope land were studied. [ Result] Results of two-year experiment showed that the dry matter accumulation, nitrogen and potassium absorption of flue-cured tobacco with water and fertilizer integrated management were still higher than those of control when fertifu.er was reduced, and fertilizer utilization ratio significantly increased, and the nutrient surplus and balance coefficient were reduced. T2 treatment with 20 % reduced fertilization increased the dry matter accumulation by 22. 28 % in maturing stage than that of conventional treatment, and promoted the absorption of nitrogen and potassium by 92. 64 % and 83. 23 % respectively in root extending stage. The apparent utilization rate, season recycling rate and economic utilization rate of nitrogen fertilizer of T2 treatment increased by 20. 98 %, 14. 6 % and 8. 6 % respectively compared with CK, even 15. 25 %, 16. 15 % and 17. 64 % higher than Tl treatment with the same amount fertilizer. Fertilizer productive efficiency of potassium increased by 35. 02 % on average, and the biggest difference of apparent utilization rate, season recycling rate and economic utilization rate between T2 and CK appeared in 2017, reaching 80. 62 %, 105. 6 % and 126. 03 % . From the soil nutrient balance, water and fertilizer- integration mode increased crop carrying capacity and reduced nutrient surplus. Compared with CK, T2 and T3 treatments reduced nitrogen surplus by 49. 3 and 54. 6 kg • hm -2, and the nutrient balance rate decreased 93. 85 and 103. 16 percentage points. The best performance on potassium balance was T2 treatment, it's potassium surplus decreased by 86. 69 kg·hm-2 compared with CK, and the balance rate fell 158. 75 percentage points. [ Conclusion] In conclusion, under the water and fertilizer integration mode, it can improve the fertilizer utilization rate and reduce the soil nutrient surplus by properly reducing the fertilizer consumption and increasing the topdressing ratio. [ABSTRACT FROM AUTHOR]

Temperature affects the growth and development of tobacco. With the frequent occurrence of extreme high and low temperature disasters, temperature stress has become one of the important factors restricting the normal growth and physiological functions of flue-cured tobacco. Low temperature stress and high temperature stress are currently the most common disasters in the seedling and maturity stages of flue-cured tobacco, which have a serious impact on the quality and yield of flue-cured tobacco. This article reviews the effects of temperature stress on physiological mechanisms such as growth and development, photosynthetic function, carbon and nitrogen metabolism, and antioxidant system of flue-cured tobacco. It introduced the research progress of related plant proteins and molecular mechanisms in temperature stress, and systematically summarizes the current stress resistance control measures for field temperature stress, including field management and spraying exogenous substances. At present, most agronomic interventions for temperature stress management may not be complete. It is necessary to understand the genetic, biochemical and physiological processes of different varieties in order to identify and select traits, enhance their high-temperature resistance mechanism, and cultivate high-temperature resistant flue-cured tobacco varieties. Looking forward to future research on temperature stress in flue-cured tobacco, including exploring local germplasm resources, cultivating heat-resistant varieties, utilizing methods such as multi omics or cross omics to deeply explore the response mechanism of temperature stress in flue-cured tobacco, developing predictive research on temperature stress in flue-cured tobacco, and developing targeted management measures for stress resistance cultivation, in order to provide scientific support for the prevention of climate disasters and the enhancement of agricultural disaster reduction efficiency for flue-cured tobacco. [ABSTRACT FROM AUTHOR]

[Objectives]The objectives of this study were to understand the effects of nitrogen-saving and density-increasing on photosynthetic characteristics and leaf structure of flue-cured tobacco(Nicotiana tabacum L.),and to provide theoretical basis for reducing the amount of nitrogen fertilizer and optimizing the structure of tobacco leaves in production.[Methods]The flue-cured tobacco variety ‘Yunyan 87’ was planted at traditional planting pattern CK(13 500 plants·hm-2,150 kg·hm-2 nitrogen level),nitrogen-saving pattern T1(13 500 plants·hm-2,135 kg·hm-2 nitrogen level),density-increasing pattern T2(16 500 plants·hm-2,150 kg·hm-2 nitrogen level),nitrogen-saving and density-increasing pattern T3(16 500 plants·hm-2,135 kg·hm-2 nitrogen level). The response laws of the photosynthetics and the physical characteristics of tobacco leaves in different parts,and the response laws of the economic traits of tobacco leaves after baking were studied.[Results]The results showed that the net photosynthetic rate of the middle and upper leaves of flue-cured tobacco reduced by 8.1%-30.7% in T1,T2 and T3 treatments. But the effect of different planting patterns on the lower leaves was not the same,wherein the net photosynthetic rate of the lower leaves reduced in T1 treatment,increased in T2 treatment,but it had no significant changes in T3 treatment. In terms of coordinating the physical and economic characteristics of tobacco leaves,the effects of T3 treatment were the most significant. In T3 treatment,the leaf area,the leaf thickness and the specific leaf weight of the upper leaves reduced by 25.8%,7.3% and 19.4% respectively,and the leaf openness of the upper leaves had no significant changes;while the specific leaf weight of the lower leaves increased by 8.9%,the stem ratio of the lower leaves reduced by 8.6%. At the same time,the output,the output value,the average price and the proportion of medium tobacco increased by 4.7%,6 000 yuan·hm-2,1.4 yuan·kg-1,and 4.7% respectively in this pattern;in terms of the tobacco leaf structure,the proportion of the upper leaves reduced significantly,but the proportion of the lower leaves and the middle leaves increased,especially the proportion of the middle leaves increased by 6.8% in T3 treatment. The photosynthetic characteristics,physical properties and economic traits of tobacco leaves were mainly affected by nitrogen fertilizer and density interaction in varying degrees. The photosynthetic characteristics of the lower leaves were mainly affected by density,and the physical characteristics were mainly affected by nitrogen fertilizer and density interaction.[Conclusions]The results of the trial indicated that the net photosynthesis rate could be raised,the structure of flue-cured tobacco leaves could be optimized and the usability of tobacco leaves could be improved,by properly increasing the transplanting density and decreasing the amount of nitrogen application. [ABSTRACT FROM AUTHOR]

In order to explore the effects of light intensities on the growth and development of flue-cured tobacco, taken two flue-cured tobacco varieties ('HY06', 'K326') as tested materials, and their physiological characteristics under light intensity at the transmittances of 65 % and 44 % for 10, 20 and 30 d were studied. The results showed that ： The plant height, stem girth, length of middle leaf, leaf number were decreased by low light density, and the budding time delayed. The nitrate reductase ( NR) activity in tobacco leaves decreased generally, while malondialdahyde( MDA) content and peroxidase(POD) activity in tobacco leaves raised first and then declined with the shading time extending. [ABSTRACT FROM AUTHOR]