Selection Of Cigar Tobacco Varieties In Southwest Hubei And Effects Of Nitrogen Application Rate And Modulation Density On Tobacco Leaf Quality

Variety,nitrogen application rate and modulation technology are the most important factors affecting the growth and quality of cigar tobacco.This experiment focused on variety,nitrogen application rate and modulation density.Field trials were conducted in southwestern Hubei from 2019 to 2020.The effects of variety,nitrogen application rate and modulation density on the quality of cigar tobacco were studied,and the effects of fermented tobacco leaves The physical properties,chemical composition and sensory quality were evaluated and analyzed.The results of the study are as follows:1.Screening of 14 cigar varieties in Southwest Hubei(1)By comparing the botanical and agronomic traits of 14 cigar varieties,Gu-4 and Gu-5 have the fastest growth in the early stage and moderate leaves,while Si-1 and Gu-2 have slow growth in the early stage and plant height.Shorter,considering the growth and development of the cigar plant,the Gu-5 variety has the best field agronomic traits,followed by the Gu-4 variety.In terms of morbidity,Shi-1 and Gu-6 varieties have weaker resistance to bacterial wilt,while Shi-2,Gu-4,Gu-5 and Nuo-2 varieties are more resistant to bacterial wilt.(2)From the analysis of physical properties,Gu-5,Yin-1 and Habanos varieties have lower stalk-bearing rates and higher tensile strength compared to other varieties.Through a comprehensive comparison of the chemical components of cigar tobacco,Habanos and Gu-8 varieties have the highest sugar content,moderate nicotine content,and the other chemical components are relatively coordinated.From the total content of neutral aroma substances and the content of new phytadiene,the Habanos variety has a higher content.(3)From the results of sensory quality evaluation,Gu-4,Gu-5 and Habanos have the best sensory quality,followed by Shi-1,Shi-2,Gu-6 and Gu-2.From the perspective of cigar leaf aroma quality,style and industrial availability,Gu-4 and Gu-5 varieties can be used as the main material or auxiliary material for hand-rolled cigars;Shi-1 and Shi-2 varieties can be used as hand-rolled cigar auxiliary materials.Gu-6,Si-1 and Duo-4 varieties can be used as machine-made cigars or hand-rolled accessories;other varieties have poor industrial availability.Taken together,Gu-4 as the eggplant variety,Gu-5 as the egg core and eggplant varieties,and Habanos as the egg core variety have the best field growth and resistance performance among the tested varieties,and the sensory quality evaluation results and industrial availability Both are better.2.The effect of different levels of nitrogen application on the quality of 3 cigar varieties(1)With the increase of nitrogen application rate,cigar tobacco plants developed better in the early stage of field growth,and tobacco plant height,maximum leaf length,maximum leaf width,stem circumference and pitch increased significantly.The content of total sugar and reducing sugar in tobacco leaves is reduced,and the content of nicotine in tobacco leaves is increased,and it has a certain promotion effect on the absorption of potassium in tobacco leaves.(2)The amount of nitrogen applied is significantly positively correlated with the leaf weight,leaf weight,and leaf thickness of tobacco leaves.(3)The increase in the amount of nitrogen application will significantly increase the total content of aroma substances and the content of new phytadiene,and the content of other aroma substances will increase under a certain amount of nitrogen application.The total amount of aroma substances will be too high when the nitrogen application rate is too high.Or it will decrease when it is too low.Through comprehensive analysis,Shi-1 variety has a nitrogen application rate of 240 kg/hm2,Gu-4 variety has a nitrogen application rate of 240 kg/hm2,and Gu-5 variety has a nitrogen application rate of 210 kg/hm2,and tobacco plants grow well in the field.,The quality of tobacco leaves is the best;the field growth and quality of the Gu-5 varieties with the same nitrogen application rate are the best.3.The effect of modulation density on nitrogenous compounds in the cigar tobacco leaf modulation process During the modulation process,as the moisture content of the cigar tobacco leaves continues to decrease,the total nitrogen content changes in a"bimodal curve" and reaches the lowest content at the end of the modulation;soluble protein degradation mainly occurs in the wilting and yellowing phases;amino acid accumulation It shows a "fast-slow-fast" change rule,which is carried out simultaneously with protein degradation;the total alkaloid content also shows a decreasing trend,but the decrease is small;the nitrate content is the lowest in the middle of the preparation,and the change is not big before and after the preparation.