Study On Curing Characteristics Of New Flue-cured Tobacco Strain CF220

This paper took new tobacco strains CF220as the research object. On the one hand, in order tostudy the curing characteristics including, yellowing characteristics, water dehydrating characteristics,leaf coloring characteristics, physiology and biochemistry and the qualities of cured leaves, by settingZhong Yan100as control, the research set up a curing experiment and a dark box test experiment. Wecan understand the yellowing, dehydration, leaf coloring law of CF220and judged its easy curingpotential and holding curing potential. On the other hand, to determine the key parameters in theyellowing and color fixing stage, the research set up two temperature treatments and three humiditytreatments in the leaf-changing stage and three humidity treatments in the muscle-changing stage. Theparameters can provide theoretical basis for formulating a bulk curing technology for CF220, which wasbeneficial to show the outstanding quality of CF220. The main results were as follows:（1）Yellowing characteristics: during the curing process, compared with Zhong Yan100, theperiod of substantial degradation of chlorophyll of the lower and cutter leave was late about12h, whilethe chlorophyll of the upper leaves of two varieties degraded synchronously. The laws of changes ofcontents of carotenoid in the cutters of the two varieties were basically similarly, but the contents ofcarotenoid in the lower and upper leaves of CF220was higher than in Zhong Yan100in various stages.In the leaf-changing stage, the ratio of carotenoid and chlorophyll in the lower and cutter leaves ofCF220was smaller than Zhong Yan100, but the laws of change of the ratio of carotenoid andchlorophyll in the upper leaves of the two varieties was basically similarly. So compared with ZhongYan100, yellowing speed in the lower and cutter leaves was slower, while the yellowing characteristicof the upper leaves was similar with Zhong Yan100.（2）Water dehydrating characteristics: the trends of the changes of water contents in the cutterleaves of the two varieties were basically similarly. In the leaf-changing and withering stage(0～60h),the water contents declined slowly, and the dehydrating speed was small. In the muscle-changing andleaf-drying stage(60～84h), the water contents declined sharply, and the dehydrating speed was big.Compared with Zhong Yan100, the period of substantial water dehydrating of the lower and upperleaves was late about12h, and the water were easy to loss.（3）Leaf coloring characteristics: the PPO activity the two varieties in the curing progressremained stable after a falling and a slight rising, and the differences between the cutter leaves of wassmall. When the dry bulb temperature was between45～47℃(60～84h), PPO activity of the leaves ofCF220was higher than Zhong Yan100, which caused browning easily.（4）Physiology and biochemistry: compared with Zhong Yan100, the two peaks of amylaseactivity of the cutter leaves of CF220ahead12h. Total sugar contents of the cutter leaves of the twovarieties remained stable after a rising. The growth process of reducing sugar contents of CF220waslate than Zhong Yan100. The total nitrogen contents remained about2.5%in the curing progress. The nicotine contents of CF220were higher than Zhong Yan100all the time.（5）The qualities of cured leaves: compared with Zhong Yan100, there was a large proportion ofvariegated group in three parts cured leaves of CF220. There was a large proportion of green group inthe cured lower leaves, while the proportion of green group in the cured cutter and upper leaves werefewer.（6）Curing characteristics of CF220: compared with Zhong Yan100, the yellowing speed of thelower leaves was slow, and it needed longer time to become yellow, but the yellowing progress was notcomplete. And it was easy to brown. There was a large proportion of variegated group and green groupin lower cured leaves. So the easy curing potential and holding curing potential of the lower leaves ofCF220were not good. The yellowing speed of the cutter leaves was slow, but the yellowing progresswas complete. There was a small proportion of green group in cutter cured leaves, and the water lossbalance between the two stages was good. So its easy curing potential was good. Meanwhile there was alarge proportion of variegated group in lower cured leaves, so its holding curing potential was not good.The yellowing characteristics of upper leaves of CF220were similar. And there was a large proportionof variegated group in upper cured leaves but green group. So compared with Zhong Yan100, the easycuring potential of the upper leaves of CF220was good, but the holding curing potential was not good.（7）Curing parameters: aiming at the cutter leaves of CF220, the key curing parameters is lowtemperatures(the dry-bulb temperature is38℃)and middle humidity(wet-bulb temperature is36℃)inthe leaf-changing stage and middle humidity (relative humidity is51%)in the muscle-changing stage.Aiming at the upper leaves of CF220, the key curing parameters was high temperatures(the dry-bulbtemperature is40℃)and middle humidity(wet-bulb temperature is38℃)in the leaf-changing stage andlow humidity in the muscle-changing stage. With the improvement of parts, should improve thetemperature in the leaf-changing stage, and decline the humidity in the muscle-changing stage,meanwhile remain middle humidity in the leaf-changing stage.