| In order to study the diversity of tobacco flue-curing characteristics of different cultivars in southern Anhui,different curing process for Yunyan 97,NC55,NC71,NC102,NC297 and K326 were carried out respectively.The relations among agronomic characteristics,color parameter values,SPAD values,polyphenol oxidase activities,moisture content,chemical components,grade proportion,quality of appearance and sensory of tobacco leaves were compared in different stages,including maturity process,the dark box conditions,flue-curing process and after flue-curing,which could be used for the quantitative determination of flue-curing characteristics index.The results are as follows:(1)In the maturity process: The height and lenth of leaves,plant height,stem circumference and node distance and other agronomic traits of all the six cultivars of flue-cured tobacco,gradually increased with the increase of the number of days after transplanting.At the time of harvest,NC71 had bigger leaves as well as better agronomic characteristics than the others.The leaves’ length of NC55 was shorter,while the agronomic characteristics were relatively worse.The activities of polyphenol oxidase of samples gradually increased with the increase of the number of days after transplanting.The oxidoreductase activities of NC55 were higher than the other cultivars,while the polyphenol oxidase activities of middle leaves of NC102 and upper leaves of Yunyan 97 were relatively lower.With the increase of days after transplanting,the color parameter values of leaves including L*,a*,b* and C* decreased slightly then gradually increased,while the H* value decreased.The SPAD value first increased slightly then gradually decreased.At the time of harvest,the SPAD value of NC102 was highest,while the values of middle leaves of NC55 and upper leaves of NC71 were lowest.(2)In condition of dark box: Moisture content of leaves and main veins gradually decreased with the increase of the dark box time of all the six tobacco cultivars.As to the decrease speed of moisture content of leaves and main vein for different stalk positions,middle leaves of NC297 and upper leaves of NC55 decreased more rapidly than the other cultivars.With the increase of the dark box time,the activities of polyphenol oxidase and the color parameter values of L*,a*,b* and C* of all the cultivars gradually increased,while H* values decreased.SPAD values of leaves gradually decreased with the increase of black box time.For the middle leaves,SPAD values of NC102 decreased more while Yunyan 97 less than the others.For the upper leaves,SPAD values of K326 decreased more while NC102 less than the others.(3)In the process of curing: Moisture content rate of leaves and main veins decreased with the increase of curing time for all the six cultivars.T3 and T4 of Yunyan 97,T1,T3 and T4 of NC55 and T1 and T3 of NC71 dehydrated fast and the values of color parameter and SPAD changed greatly,Dehydration speed of T2 was rather low;T4,T5 and T6 of NC102 dehydrated fast and the values of color parameter and SPAD changed greatly.T1 of NC297 dehydrated slowly and values of color parameter and SPAD changed slightly.T4 of K326 dehydrated fast,and the values of color parameter and SPAD changed greatly.(4)After flue-curing: For Yunyan 97,the upper grade proportion of T1 was highest among the other cultivars,and quality of appearance and sensory and the coordination of chemical components of T2 were better.For NC55,T3 had higher upper grade proportion and better quality of appearance and sensory,and T6 had better coordination of chemical components.For NC71,T4 had higher upper grade proportion,and T5 had better quality of appearance and sensory and coordination of chemical components.For NC102,T2 had higher upper grade proportion,and T1 had better appearance quality and coordination of chemical composition.For NC297,T4 had better quality of appearance and sensory and coordination of chemical composition.For K326,T5 had better upper grade proportion and appearance quality.(5)The curing characteristics of six different flue-cured tobacco cultivars differed greatly.Yunyan 97 had best quality in the condition of medium humidity in yellowing stage and low speed of heating-up in the stage of color fixing,which was in need of timely transfer of fire after fully yellowing.NC55 had best quality in the condition of high humidity in yellowing stage and low speed of heating-up in the stage of color fixing,which was in need of extension of color fixing time.The most suitable curing environment for NC71 was medium humidity in yellowing stage and medium speed of heating-up in the stage of color fixing heating color.It would be appropriate to reduce the time of yellowing stage.NC297 was suitable for high humidity in the yellowing stage,and low speed of heating-up in the stage of color fixing.Therefore it would be appropriate to slow down the speed of heating-up in the stage of color fixing to prevent badly flue-curing.The most suitable curing environment for NC102 was similar to NC71,which was medium humidity in yellowing stage and medium speed of heating-up in the stage of color fixing,and also in need of timely transfer of fire after fully yellowing.K326 had strong ability to adapt to the curing environment.The most suitable environment for K326 was high humidity in yellowing stage and low speed of heating-up in the stage of color fixing.Accurate control of the yellowing stage time and maintaining of the high humidity in the stage of color fixing was the benefit for the degradation of the macro-molecules.aintain a high humidity of a given color,in order to facilitate explanation macromolecules. |
