Studv On Climatic Indexes Of Upper Six Flue-cured Tobacco Leaves In Central Henan Province

The quality of flue-cured tobacco is comprehensively affected by the varieties,ecology,and cultivation measures.Under certain varieties and cultivation conditions,the climatic factors play a key role in the formation of the quality of upper six leaves and the display of the strong-aroma style.It has been several years since the production and utilization of the upper six leaves in Central Henan Province,but due to the lack of systematic research on climatic factors,the upper six leaves have low maturity,poor aroma,and low adaptation rates among high-end brands.Therefore,based on the systematic development of key technologies for the production of high-quality upper six leaves,it is necessary to establish a corresponding standardized climate indicator system to fully exploit the production quality potential of the upper six leaves.This study was conducted with field experiment in three consecutive years from 2015 to 20 1 7 in Wang Luo town,Xiangcheng County,Henan Province.Exploring the effects of transplanting and harvesting time on climatic factor,and economic characters and quality characteristics,as well as the relationship between climatic factors and the quality characteristics of upper six leaves of flue-cured tobacco in central Henan provinces and to screen out the key climate factors affecting the production,quality and style characteristics of the upper six leaves,determining the index range.It aims to provide basis and support for the establishment of a high-quality tobacco leaf production technology system in central Henan province.The main conclusions are as follows:1.Within the set transplanting period,with the delay of transplanting time,during the upper six leaves extension period,the upper six leaves mature period,and the whole growth period,>0? accumulated temperature,>10? accumulated temperature,>20?accumulated temperature,daily temperature range>20? days,the highest temperature>30?days and rainfall,light hours showed a gradual decrease trend.the average temperature and the accumulated temperature>20? during the extension period were all relatively higher with the April 25 transplanting treatment.The rainfall during the growing period of flue-cured tobacco was relatively higher on April 25 and May 5 transplanting treatment which were 361.53 mm and 361.24mm,respectively.During the mature period of the upper six leaves,the average temperature at the time of transplantation before May 5 can reach above 25?,however,when the transplantation on 15 May and the harvest period was delayed by 12 d,the average temperature was lowest at 24.6?.If the temperature is lower than 25?,the strong aroma style of tobacco leaves is weakened.With the harvest time was postponed,The average temperature gradually decreased and the maximum temperature>30? days did not change significantly..all accumulated temperature indicators and light hours showed a significant increase,reaching the highest with a delay of 12d,in which the mature effective accumulated temperature>20? in different harvest time varied from 187.88 to 313.3?.The transplantation delay before May 5 From 6 to 12 d,the effective accumulated temperature of>20? can reach above 240?,with a range of 242.48?313.3?.In the process of the growth of the upper six leaves,the average temperature,daily temperature range,and the maximum temperature were effected more by the transplanting time than the harvesting time,and the accumulated temperature,>20?days and light hours was closely related to the harvesting time.Under the transplanting conditions before May 5,the average temperature and the maximum temperature>30?days did not change significantly with the delaying harvest time,but the accumulated temperature increased significantly and continuously.2.The transplanting time and harvesting time significantly affected the economic traits of upper six leaves,and there was a very significant interaction effect.The effect of transplanting time on yield and output value was greater than that of harvesting time,while the harvesting time had a greater influence on the proportion of superior tobacco,single leaf weight and average price of upper six leaves.Transplanting from April 25 to May 5 gave rise to higher yield and output value.Delaying harvest by 6 d and 12 d resulted in no difference in average price,but it was significantly higher than other treatments,with the proportion of superior tobacco increased significantly by 10.66%and 15.39%respectively compared with the normal harvest.The transplanting time was closely related to strong-aroma style of upper six flue-cured tobacco leaves,and the transplanting time no later than May 5 was beneficial to the display of the strong-aroma style of upper six leaves.With the delay of the transplanting time from April 15 to May 5,the potassium-chlorine ratio of upper six leaves increased,and the flammability was better.The content of neutral aroma components was highest when transplanting tobacco from April 25 to May 5.The harvesting time had a great influence on the quality of upper six leaves,as harvesting time delayed,the protein content,starch content,sugar-alkali ratio of upper six leaves decreased,and tended to be optimum when the harvesting time was delayed for 12 days.The sensory quality of upper six leaves showed an increasing trend as a whole as harvesting time delayed,and was the best under a delay of 12 days with significant increase of total amount of neutral aroma components.Comprehensive analysis showed that transplanting from April 25 to May 5 and harvesting with 6-12 days delayed were conducive to improvement of economic characters,quality,and the display of strong-aroma style of upper six tobacco leaves in central Henan.3.The typical full-flavor style of upper six tobacco leaves was significantly correlated with the number of days having maximum temperature>30?,average temperature during the maturing period,and accumulated temperature of>20?.The full flavor style of upper six tobacco leaves was more significant when the days with daily optimum temperature>30?during the whole growth period and maturing stage were 25?33d and 52?70d,respectively.and the average daily temperature during mature stage was 25.26?27.14?.Within the limit of this study,the full-flavor style of upper six leaves also increased with the increase of accumulated>20? temperature.The quality of upper six tobacco leaves was more closely related to the accumulated temperature>20? days,light hours and rainfall during the whole growth period and the maturing period.Tobacco's needs for climatic such as light temperature according to the optimum transplanting and harveseting time,The quality of upper six tobacco leaves was more prominent when the accumulated temperature of>0?,>10?,>20? was 1122.97?1268.26??692.97?871.39??262.97?313.3?,respectively,as well as the>20? days are 51?55d,light hours are 264.0?347.2h for the maturing stage and 2018.0?2332.8??1257.9?1425.9??497.9?544.5?,and>20?days are 76?94d,light hours are 464.5?545.5h,respectively,for the whole growth period of upper six leaves.The high temperature and sufficient sunlight during growth and maturity of upper six leaves are essential for the formation of high quality and typical full-flavored flue-cured tobacco.Properly delaying harvest of upper tobacco leaves and so increasing the accumulated temperature would ensure high quality upper tobacco leaf production and at the same time maintain typical full-flavor style.