Analysis Of Quality Of Light-sweet Flavor Style Flue-cured Tobacco Leaf And The Characteristics Of Agro-geological Background As Well As Soil Nutrient In Guizhou Wumeng Tobacco-growing Area

Tobacco leaves of Wumeng tobacco-growing area in Guizhou were used to analyze thequality differences among typical light-sweet flavor style, light-sweet flavor style and weaklight-sweet flavor style from aspects of appearance quality, physical property, chemicalcomponent and sensory characteristics. The ecological conditions of agro-geological backgroundand soil nutrient characteristics that influence the form of different flavors were compared. Thediscrimination models of different light-sweet flavor styles based on agro-geological background,soil nutrient and chemical components of tobacco were established. The main results are asfollows.1. The tobacco quality characteristic of different light-sweet flavor styles in Wumengtobacco-growing area was analyzed.(1) In terms of appearance characteristic, the scoredifferences of chrominance and leaf structure among different flavor styles reached to extremelysignificant level. The chrominance score of light-sweet flavor and typical light-sweet flavor stylesignificantly higher than weak light-sweet flavor style, the leaf structure score reduced with theenhancing of light-sweet flavor feature, and the score of typical light-sweet flavor and light-sweetflavor style significantly lower than weak light-sweet flavor style.(2) In the matter of physicalproperty，the differences of the length and width of leaf among different flavor styles reached toextremely significant level, the weight difference of single leaf showed significant level, and thestem ratio and leaf density had no significant differences. The length, width and weight of leafincreased with the enhancing of light-sweet flavor feature, and the typical light-sweet flavor andlight-sweet flavor style significantly higher than weak light-sweet flavor style.(3) In terms ofchemical component, the contents of protein, total nitrogen, total sugar, reducing sugar andpotassium among different flavor styles had significant or extremely significant differences, but the other indexes had no significant differences. The contents of protein and total nitrogendecreased with the enhancing of light-sweet flavor feature, and the typical light-sweet flavorsignificantly lower than light-sweet flavor style and weak light-sweet flavor style. However, thecontent of total sugar, reducing sugar and potassium increased with the enhancing of light-sweetflavor feature, and the content of total sugar and potassium of typical light-sweet flavorsignificantly higher than light-sweet flavor style and weak light-sweet flavor style, the reducingsugar content of typical light-sweet flavor had no significant differences with light-sweet flavorstyle, but significantly higher than weak light-sweet flavor style. On the whole, compared withweak light-sweet flavor, the typical light-sweet flavor tobacco were of higher sugar content, lowernitrogen content and lower protein content.(4) On the aspect of sensory quality, the total score andthe scores of sensory indexes except combustibility among different types had significant orextremely significant differences. The total score and scores of aroma quality, aroma quantity,offensive odor, irritancy, taste, aftertaste, fine and soft degree increased with the enhancing oflight-sweet flavor feature, and the sensory indexes scores of typical light-sweet flavor allsignificantly higher than light-sweet flavor style and weak light-sweet flavor style, the total scoreof typical light-sweet flavor significantly higher than weak light-sweet flavor style.2. The agro-geological background characteristics of light-sweet flavor style of flue-curedtobacco in Wumeng tobacco-growing area were identified. The results indicated that carbonateand clastic sedimentary rocks were mainly soil parent rocks for typical light-sweet flavor style,only carbonate sedimentary rocks were for light-sweet flavor style, while carbonate and claysedimentary rocks were for weak light-sweet flavor style. Although the sources and compositionsof parent material that affect the formation of flue-cured tobacco styles were different, all weredominated by slope sediments. Yellow brown soil and purple soil were mainly soil types fortypical light-sweet flavor style, and yellow soil was not included. Yellow brown soil, yellow soiland limestone soil were for light-sweet flavor style, while yellow soil and limestone soil were forweak light-sweet flavor style, and the yellow brown soil had the least proportion. Furthermore, theresults suggested that high-middle mountain landform was mainly used for typical light-sweetflavor style, the share of high-middle and middle mountain landform for light-sweet flavor stylewas equivalent, and the middle mountain landform was for weak light-sweet flavor style. 3. The soil nutrient characteristics of light-sweet flavor style of flue-cured tobacco inWumeng tobacco-growing area were analyzed. The content differences of soil organic matter,available nitrogen, total potassium, effective potassium and water-soluble chloride that influencedthe form of different light-sweet flavor style of flue-cured tobacco reached to extremely significantdifference, the differences of effective copper content reached to significant difference, while theother indexes had no significant difference. The contents of organic matter, available nitrogen,total potassium and water-soluble chlorine in the soil for typical light-sweet flavor style weremoderate, but lower compared with light-sweet flavor and weak light-sweet flavor style, while theavailable potassium content was significant higher than light-sweet flavor and weak light-sweetflavor style.4. The mathematical models for identifying different light-sweet flavor types of flue-curedtobacco were established by discriminant analysis that respectively taking agro-geologicalbackground, soil nutrient, and tobacco leaf chemical components as variable. The discriminantfunctions were established based on the agricultural geological background, and the functions thatindexes of soil types, soil parent rocks, parent material and elevation were introduced to werevalid to distinguish different types through variance analysis. The discriminant functions werere-discriminated by using the methods of self and mutual test with discrimination accuracy bothbeing64.68%, so the discriminant functions were verified well in discriminant results. Thediscriminant functions were established based on the soil nutrient, and the functions that indexesof organic matter, pH, total nitrogen, available nitrogen, total phosphorus, effective phosphorus,total potassium, effective potassium, boron, water-soluble chloride, effective sulfur, effectivecopper, effective zinc and effective iron were introduced to were valid to distinguish differenttypes through variance analysis. The discriminant functions were re-discriminated by using themethods of self and mutual test with a discrimination accuracy being81.27%and75.33%respectively, so the discriminant functions were verified well in discrimination results. Thediscriminant functions were established based on the chemical components of tobacco leaves, andthe functions that indexes of nicotine, total sugar, reducing sugar, total nitrogen, chlorine,potassium, protein, sugar/alkali, alkali/nitrogen and potassium/chloride were introduced to werevalid to distinguish different types through variance analysis. The discriminant functions were re-discriminated by using the methods of self and mutual test with a discrimination accuracy being62.51%and57.69%respectively, so the discriminant functions were verified well indiscrimination results.