| With using the major meteorological data of nearly 40 years in term of temperature,sunshine hours and rainfall which had a larger effect on flue-cured tobaccos in Wumeng tobacco-growing areas,the characteristics of climatic factors at flue-cured tobacco growth stages were analyzed among different months and years.And the climate differences of different altitudes in the areas were compared.At the same time,the tobacco leaf samples were collected from 87 villages and towns in Wumeng tobacco-growing areas and the quality characteristics of every tobacco leaf sample were determined.According to aroma scores of the tobacco leaf samples,light-sweet flavor style of flue-cured tobaccos in Wumeng tobacco-growing areas could be divided into three subtypes.The sensory quality characteristics of different subtypes were analyzed and the climate differences of the areas where the tobaccos of different subtypes grew were compared.The major conclusions of the research were as follows:1.The characteristics of climatic factors in terms of temperature,sunshine hours and rainfall at flue-cured tobacco growth stages were analyzed.The results indicated that:(1)On the aspect of temperature,the average temperature in nearly 40 years at flue-cured tobacco growth stages from May to August was 18.76?,and the temperature had a smaller change amplitude and its coefficient of variation was 2.28%.Variabilities of the temperature of this tobacco-growing areas were weaker and there existed narrow fluctuations in different years.The linear trend analysis showed that the temperature of the root extending period and early maturing stage had a downward trend,of which the temperature of early maturing stage dropped significantly,while the temperature during vigorous growth stage had a significant upward trend.Mutation analysis showed that the saltation of temperature at flue-cured tobacco growth stages in Wumeng tobacco-growing areas occurred in 1998 in last 40 years.(2)On the aspect of sunshine hours,in this tobacco-growing areas sunshine hours from May to August had a rough change trend of rising after falling,the average was 604.31 h.The coefficient of variation of sunshine hours of each month was up 20%,which indicated that there existed a larger difference in different years.The linear trend analysis showed that Wumeng tobacco growing areas were provided with an adequate sunshine duration as a whole.The sunshine hours of different development stages of the flue-cured tobacco could all meet the needs of the normal growth of tobaccos but they all showed a trend of decrease year by year,and the trend was more significant at the middle and later periods.Mutation analysis showed that the saltation from more to less of sunshine duration at flue-cured tobacco growth stages occurred in 1985.(3)In terms of rainfall,the average of rainfall from May to August was 643.94 mm.The rainfall was adequate at flue-cured tobacco growth stages,but the coefficient of variation of rainfall of each month was up 20%,which indicated that there existed widely fluctuations in different years.The linear trends of rainfall of the three stages of the flue-cured tobacco growth were not significant,but the change amplitudes of rainfall during the root extending period and maturing period were larger and the interannual stability was poorer.The rainfall during maturing period was more and had an slightly increasing trend.Mutation analysis showed that rainfall during field period did not have a significant saltation.2.According to the sources of meteorological data,the altitude of Wumeng tobacco-growing areas could be divided into three groups which included low altitude(?1500 m),middle altitude(1500~2000 m)and high altitude(?2000 m).The characteristics of climate factors of different altitudes in the areas were analyzed by difference analysis.The results showed that heat indexes had significant difference among different altitudes,and the differences of the average temperature of each growth stage,cumulative temperature during field period and available days during field period showed low altitudes > middle altitudes > high altitudes.The sunshine hours of each growth stage among different altitudes had significant differences at 0.05 level.The sunshine hours of the root extending period showed that low altitudes were significantly up middle altitudes and the middle altitudes were significantly up high altitudes.The differences of sunshine hours during vigorous growth period between low altitudes and middle altitudes did not reach significant levels,but they were all significantly down high altitudes.The differences of sunshine hours during maturing period between low altitudes and middle altitudes did not reach significant levels,but they were all significantly up high altitudes.The rainfall of the root extending period and field period in high altitudes were significantly up low altitudes and middle altitudes.The differences of rainfall during vigorous growth period between middle altitudes and high altitudes did not reach significant levels,but they were all significantly up low altitudes.The rainfall of maturing period of middle altitudes and high altitudes were all significantly down low altitudes.3.According to aroma scores of tobacco leaf samples,light-sweet flavor style of flue-cured tobaccos in Wumeng tobacco-growing areas could be divided into three subtypes: typical light-sweet flavor style,light-sweet flavor style,weak light-sweet flavor style.Typical light-sweet flavor flue-cured tobacco-growing areas included sixteen villages and towns,mainly distributed in Weining.Light-sweet flavor flue-cured tobacco-growing areas included twenty-four villages and towns,mainly distributed in Weining and Hezhang.Weak light-sweet flavor flue-cured tobacco-growing areas included forty-seven villages and towns,mainly distributed in Hezhang and Nayong.The sensory quality characteristics of different subtypes were analyzed by difference analysis.The results showed that the scores including smoke consistency,quality of aroma,volume of aroma,inductivity,downy extent,fruity sense and aftertaste of typical light-sweet flavor flue-cured tobaccos were up the scores of light-sweet flavor flue-cured tobaccos and weak light-sweet flavor flue-cured tobaccos while the score of smoking strength was the lowest during three subtypes.Typical light-sweet flavor flue-cured tobaccos had good aroma quality including rich aroma volume,exquisite,soft and fruity smoke,less offensive and irritating odor,clean and comfortable aftertaste.4.The climate and altitude differences of the areas where the tobaccos of different subtypes grew were analyzed.The results indicated that with light-sweet flavor style enhancing,altitudes were higher and higher while heat indexes all reduced gradually,and the differences of the heat indexes among different subtypes had significant differences at 0.05 level.Typical light-sweet flavor tobacco-growing areas had the most sunshine durations during vigorous growth period and weak light-sweet flavor tobacco-growing areas had the minimum,while sunshine durations during the root extending period,maturing period and field period showed the contrary trend.In addition to the rainfall of maturing period,other rainfall indexes among three subtypes existed significant differences and with light-sweet flavor style enhancing,the rainfall during growth and development period presented an increasing tendency. |
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