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【Objective】Since 2017, an anthracnose was extensively occurred on P. cyrtonema in the Hunan province of China. The present paper aimed to clarify the pathogen and the sensitivity of the pathogen to fungicides.【Method】The pathogen fungal stains were isolated from symptomatic leaves and identified by both morphological and molecular tools using both the ITS, ACT, CHS-1 and GPDH gene regions. Pathogenicity was confirmed with inoculation experiments that fulfilled the Koch's postulates. On this basis, the indoor toxicity of 5 fungicides to the pathogen was determined by mycelial growth rate method.【Result】By tissue isolation, 16 morphologically identical strains were isolated from the diseased diseased leaves of four plantation in Hunan province, and the colony morphology and culture characteristics of the strains were observed to confirm that they were Colletotrichum sp.. Molecular identification of CLHJY4-3 determined that the pathogen was C. spaethianum. The pathogenicity was confirmed by inoculation and the Koch's postulates was verified. The average growth rate of the hyphae of this pathogen was 1.1 cm/day. Conidia were 18.4 to 25.0 μm long and 3.9 to 5.3 μm wide. The seta were dark brown, with 2-3 septs, 79-107 μm long. The results of indoor toxicity determination showed that among the five agents, prochloraz had the strongest inhibitory effect on hyphal growth, EC50 was 0.031 μg/mL, followed by pyraclostrobin and tebuconazole, with the EC50 of 0.049 and 0.252 μg/mL, respectively. The inhibitory effects of thiophanate-methyl and carbendazim were relatively poor, with the EC50 of 2.911 and 1.763 μg/mL, respectively. 【Conclusion】C. spaethianum was the pathogen of leaf spot of P. cyrtonema in Hunan province. Moreover, prochloraz and pyraclostrobin were screened as better fungicides against the pathogen fungus. [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 explore the influence of the production area on the growth of Dendrobium carulidum and the composition of metabolites, the different metabolites of D. candidum from different production areas were screened. [ Method] The present study used gas chromatography-mass spectrometry ( GC-MS) combined with principal component analysis ( PCA), partial least square discriminant analysis ( PLS-DA) and other multivariate statistical analysis methods for non-targeted metabolomics analysis of Dendrobium mobile samples from different productions. [ Result] The principal component analysis of Dendrobium metabolites from different producing areas can distinguish cultivated varieties from wild varieties except Hunan, combined with partial least square discriminant analysis and T test (Student's-test) to compare Hunan wild species and indoor cultivated species to carry out differential metabolite analysis. The cluster heat map analysis ( HCA) was used to verify the differential metabolites, and 20 extremely significant different metabolites were found finally including Propionic acid, Threonine ( P < 0. 01). [Conclusion] There are 20 significantly different metabolites between wild D. candidum and cultivated varieties, mainly organic acid and polysaccharide metabolites. The study can provide a theoretical basis for the identification and authenticity of D. carulidum. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to evaluate the potential of white clover (Trifolium repens L.) as forage grass and ecological engineering plant on paddy field ridges in southern China. [Method] The clover was planted on the ridge of paddy fields in Ilengnan, Ilunan province and Jiangyou, Sichuan province in the spring of 2015. Cabover-ground parts, mainly leaves and petioles, were harvested monthly from July of 2016 to June of 2017. Dry matter was weighted after desiccation in a stove at 105 °C for 15 minutes and 70 °C for 24 hours. Dry samples harvested in the same season were mixed after storing at -20 °C . The contents of crude protein, nitrogen, phosphorus and potassium of such mixed samples were then determined by the standard procedures. The antagonism experiment with Alternant her a philoxeroides was conducted by face-to-face cultivation in concreted circles located in a plastic greenhouse from July of 2017 to March of 2018. [Result] At the experiment site in Sichuan, the highest dry matter weight of the white clove was obtained at the first harvest and the dropped until January of 2017 and increase gradually till the end of the experiment. It dropped also in Ilunan after the first harvest but started to increase since August and reached the highest point in April of 2017. The contents of crude protein, nitrogen and phosphorus were the highest in the first quarter at both sites. The content of potassium was the highest in the third quarter at Jiangvou but in the second quarter at Ilengnan. In the antagonism experiment, the growth of A. philoxeroides under each treatment was obviously better than that of clover in the summer, but white clover grew significantly better than A. philoxeroides under each irrigation regime and dominated the community in terms of occupying area, fresh weight and dry weight. [Conclusion] White clover on paddy didges has shown strong regeneration ability both in Sichuan and Hunan and could be used as high-quality forage and green manure crop. It could strongly inhibit the growth of A. philoxeroides at low temperature and soil humidity. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to clarify the genetic diversity and composition of non-toxic genes of Magnaporthe oryzae in Taojiang. [Method] Genetic diversity of 29 M. oryzae isolated and purified from several late rice varieties in Taojiang disease nursery was analyzed by 8 pairs of SSR primers. And nontoxic gene of 19 isolates were identified through 18 near-isogeniclines(NILs) whose resistance gene to blast were known. [Result]The results indicated that under the 0. 70 similarity coefficient and 0. 30 difference coefficient level, the total isolates of twenty-nine could be divided into seven genealogies. The dominant genealogy 1 contained 12 isolates, accounting for 41.3 % of the total isolates. The V genealogy contained 7 isolates, accounting for 24. 1 % of the total isolates. The other 5 genealogies contain 1 -3 isolates, accounting for 34.6 % of the total number of isolates. The pathogenic frequency (pathogenic frequency = the number of susceptible rice varieties / the number of total tested rice varieties x 100 %) ranged from 35 % to 75 % , and there were 3 strong pathogenic iso-lates (pathogenic frequency > 70 %) which accounted for 15. 7 % of the total isolates ;7 isolates were highly pathogenic (70 % > pathogenic frequency ^50 %) , accounting for 36. 8 % of the total isolates. Nine medium pathogenic isolates (50 % > pathogenic frequency ^20 %) , accounted for 47. 5 % of the total isolates, and the average pathogenic frequency of the tested isolates was 49.86 % . The virulence frequencies of 19 isolates to NILs (virulence frequencies = the number of isolatesto be tested the virulence with NILs / the number of all isolates x 100 %) were identified by avirulence gene, it was shown that more than 70 % of the virulent genes what with highly virulent were Pi-ks, Pi-ztand Pi-ta. The resistance gene whose virulence frequency was between 50 % and 70 % with medium virulence were pi-kp , pi-z5 , pi-t, pi-sh and Pi-5. The virulence frequency of the other resistance genes was less than 50 %. [Conclusion] The population of Pyricularia oryzae in Taojiang, Hunan province has abundant genetic diversity and complicated pathogenicity differentiation. The resistance genes Pi-3, Pi-i, Pi-11, Pi-19 and Pi-12 have excellent resistance to M. oryzae in Taojiang area and can be used in disease resistance breeding. [ABSTRACT FROM AUTHOR]