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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 comprehensively and systematically study organic matter in arable soil as well as pH spatial distribution in the entire region of Guizhou, rationally plan and exploit cultivated land, and provide support for food security. [Method] Statistical analysis and ArcGIS space interpolation method were combined to analyze the spatial distribution of organic matter and pH in cultivated soil under the traditional cultivation pattern in Guizhou, and to study the influencing factors. [Result] The spatial distribution of soil organic matter content in cultivated land was uneven, with average content of 31. 13 g/kg, but the organic matter in cultivated land of Guizhou stayed abundant in general, and the content in each region showed as Liupanshui ( 52. 39 g/kg) > Guiyang ( 36. 01 g/kg) > Qianxinan (34. 02 g/kg) > Bijie(33. 89 g/kg) > Qiannan(32. 97 g/kg) > Anshun(31. 28 g/kg) > Qiandongnan(29. 92 g/kg) > Zunyi(25. 59 g/ kg) > Tongren(23. 01 g/kg). The pH of arable soil in Guizhou were 3. 99 - 8. 66, with the average value of 6. 06, and 90. 55% of the arable soils were dominantly acidic, weak acidic and neutral, accounting for 29. 48%, 38. 11 % and 22. 96% respectively. In the study area, the soil types display yellow-brown soil had the highest organic matter content and red soil had the lowest organic matter content The organic matter content with different soil utilization types was paddy field > irrigated land > dry land, while the pH showed as irrigated land > paddy field > dry land. [ Conclusion] The spatial distribution of organic matter content in arable soil of Guizhou province is uneven because of terrain, elevation and other influence factors, but the overall content stayed abundant. The spatial distribution of organic matter demonstrated as high in the west and south, low in the east and north. The pH of the provincial arable soil is mainly acidic or weak acidic, and its spatial distribution appeared uneven, showing a macro pattern of high in the west and north, low in the east and south. Soil type has a significant influence on pH of the soil, while it has insignificant impact on soil organic matter. Land utilizing type has extremely significant effect on both soil organic matter and pH. [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]

[ Purpose] The present paper aimed to study the physical properties, soil enzyme activities and their correlation characteristics of wild Bletilla striata soil in different producing areas in Guizhou, so as to provide a theoretical basis for realizing high yield and quality of B. striata artificial cultivation. [ Method] 8 soil sample plots for the wild B. striata were collected in Guizhou province to detect and analyze the soil physical and enzyme activity index characteristics and the correlation between them. [ Result]The soil density was between 2. 06 -2. 55 g/ cm³ with weak variation. The soil texture was mainly clay loam and sandy loam. In most soils, the proportion of the > 0. 25 mm size soil water-stable aggregates reached 70% . The distribution of the soil water-stable aggregates size fraction were different, 2 - 5 mm size fraction was the dominant size fraction in 4 soil plots, < 0. 25 mm size fraction was the dominant size fraction in 3 soil plots. The dominant size fraction of soil micro-aggregate was 0. 25 -0. 05 mm size fraction. The activities of urease, acid phosphatase and sucrase in soil were significantly different with strong variation. The activities of catalase in soil were not significantly different with weak variation. Soil enzyme activity was strongly influenced by the soil density, soil aggregates and microaggregates. There was a significant positive correlation between urease and acid phosphatase, which could promote each other. [Conclusion] Guizhou wild B. striata has strong adaptability to soil environment. It mainly grows in sandy soil or clay with soil clay content less than 25 %, and some wild B. striata can also grow in clay with soil clay content more than 30% ; Soil specific gravity, soil aggregates and micro aggregates are important factors affecting soil enzyme activity of B. striata. The suitable soil specific gravity is 2. 06 - 2. 55 g/ cm³, the dominant particle size is 2 - 5 mm or < 0. 25 mm, and loam is the best soil texture; Urease and acid phosphatase can promote each other. [ABSTRACT FROM AUTHOR]

[Objective] The objective of the paper is to provide a reference for screening high-yield and good-quality tea cultivars suitable for planting and popularization in Guizhou. [Method] By using Li-6400XT portable photosynthetic system and ethanol extraction-colorimetry, taking Furling White Tea as the control, the leaf photosynthetic physiological indexes, leaf functional traits and their correlations of 15 tea cultivars (lines) cultivated in the same habitat were measured to determine the photosynthetic potential of 15 tea cultivars (lines). [Result] There were differences among photosynthetic physiological indexes, photosynthetic pigment content and leaf functional traits of 15 tea cultivars (lines). Mabianlv, Zhenong 901, Chuannonghuangyazao and Chuanmu 28 had higher photosynthetic characteristics, and photosynthetic efficiency was stronger, P n was 8. 89 - 9. 81 f.LmoV (m2 • s), which had higher high-yield potential compared with other 11 tea cultivars (lines). Chuannonghuangyazao was an etiolation cultivar. Its photosynthetic pigment content was lower, and was equivalent to Furling White Tea (CK). P n, SLA and WUE were higher. The cultivar was featured with higher etiolation specificity, photosynthetic capacity and water use efficiency, which had better cultivation and utilization prospects. Zhongxuan 10, Zhongcha 112 and Baojing Golden Tea had higher WUE, respectively 3. 77 - 3. 91 f.LmoVmmol, and lower transpiration rate[2. 08 - 2. 20 mmoV (m2 • s) J. The three cultivars (lines) had stronger drought resistance potential, which could be researched on resistance indexes deeply. [Conclusion] From the perspective of photosynthetic characteristics, Mabianlv, Zhenong 901, Chuannonghuangyazao and Chuanmu 28 have higher photosynthetic capacity, which can be cultivated and popularized in Guizhou. [ABSTRACT FROM AUTHOR]

[Objective] In order to understand the content characteristics and ecological risk of heavy metals in agricultural soils in small-scale areas of karst regions, the present paper provides reference for the utilization of land function and the protection of cultivated soil environment. [Method] A total of 27 sites were laid on soil on agricultural land in the southwestern of Guizhou Province, samples of surface soil ( 0 - 20) cm were collected, and 8 heavy metal elements such as pH and Cd, Hg, As, Pb, Cr, Cu, Zn and Ni were analyzed and determined. The 'Soil Environmental Quality-Soil Pollution Risk Control Standard for Agricultural Land' (GB15618 - 2018) was used as the evaluation criteria to analyze its distribution characteristics, ecological risks and sources. [Result] The results showed that the soil pH in the study area was 5. 46 to 8. 07, and the average contents of heavy metals Zn, Cr, Pb, Ni, As, Cu, Cd and Hg were 154. 24, 153. 71, 64. 25, 61. 76, 50. 38, 49. 86, 0. 41 and 64. 25 mg/kg, respectively. The soil pollution index of agricultural land in the study area was 1. 68 and 1. 38, respectively. The hazard index (IR) value of 8 kinds of heavy metals was 69. 00, which was less than the limit of ecological hazard (IR = 150) . Cd and Pb, Hg and As, Cu, Zn, Ni, As and Cu, Zn, Ni, Cr, Cr and Cu, Zn, Ni, Zn and Ni have homology respectively, and there is compound pollution. The results of the main component analysis show that As, Hg, Cr, Cu, Zn, Ni have a higher load in the first main component, the variance contribution rate is 57. 565%, the content is mainly caused by the long-term application of heavy metal fertilizer; Cd and Pb have higher load in the second principal component, and their variance contribution rate is 80. 277%. The higher content is mainly due to the higher content in the parent material. [Conclusion] The soil pH of agricultural land in the study area is 5. 46 - 8. 07 which has been polluted by As and Cd to different degrees. Cr and Ni pollution is still clean range; Hg, Pb, Cu and Zn are in the clean range. The pollution level is slight ecological hazard [ABSTRACT FROM AUTHOR]