Evaluation on tobacco germplasm resources chemical quality based on principal components analysis and cluster analysis

ObjectiveIn this study,chemical quality of tobacco germplasm resources were evaluated and high quali-ty tobacco germplasm resources were screened out to provide reference for tobacco parent breeding selection and utiliza-tion of the resources.MethodTen chemical indexes for 124 tobacco germplasm resources were standardized,and princi-pal component analysis and cluster analysis were conducted. The well recognized proper scope for tobacco chemical com-ponents were adopted to evaluate the chemical quality of all tobacco germplasm resources.ResultThe comprehensive score of principal component was 2.04 forⅠgroup,including 42 germplasm resources. Their main chemical components indexes were in proper scope,including reducing sugar,total sugar,total nitrogen,nicotine,ratio of nitrogen-nicotine, ratio of sugar-nicotine,protein,difference between total sugar and reducing sugar. They contained high potassium con-tent,and had sound comprehensive chemical quality. Most approved varieties and elite resources belonged to this group. For Ⅱ group,the comprehensive score of principal components was 2.450,including 7 germplasm resources. Their indexes like total sugar,reducing sugar,total nitrogen,nicotine,ratio of sugar-nicotine,ratio of nitrogen-nicotine and protein were in proper scope,the chemical components were coordinating,and the tobacco quality was fine. The comprehensive score of principal components was-1.360 for Ⅲ group,including 20 germplasm resources. They contained proper compo-nents like total nitrogen,less proper components including ratio of sugar-nicotine,nicotine,total sugar and redu-cing sug-ar,and standardized values of potassium,chlorine,difference between total sugar and reducing sugar,protein were im-proper. Their chemical quality was moderate. The comprehensive score of principal components was-1.180 for Ⅳ group, including 11 germplasm resources. Their total nitrogen,potassium and chlorine were in proper scope,total sugar,reduc-ing sugar and ratio of nitrogen-nicotine were less proper,which indicated that the chemical quality was at medium level. In terms of Ⅴ group ,comprehensive score of principal components was-1.110,including 13 germplasm resources. They had proper components like total nitrogen,nicotine,chlorine,ratio of nitrogen-nicotine,less proper components such as total sugar,reducing sugar,ratio of sugar-nicotine and difference between total sugar and reducing sugar,potassium content was low,and the overall quality was fine. The comprehensive score of principal components was-1.380 forⅥgroup,in-cluding 23 germplasm resources. They contained proper components including total sugar,reducing sugar,total nitrogen, ratio of sugar-nicotine,less proper components like nicotine,potassium,chlorine and ratio of nitrogen-nicotine,the rest indexes were improper. The comprehensive score of principal components was-3.700 for Ⅶ group,including 8 germplasm resources. They contained proper components of ratio of nitrogen-nicotine,less proper components of total nitrogen, chlorine and potassium,but the rest components were improper.ConclusionThe chemical components of different to-bacco germplasm resources have significant difference. There are a group of germplasm resources with fine chemical qual-ity which can be used as parents in tobacco variety breeding:Jinxing 6007,Baihau 205,Chunlei 1,Chunlei 3,G-28, Zhongyan 90,K326,Kutsaga 51E,Baoshan tuanye,Cunjinyan,Panyuanhuang,581 Yongding 1,Kutsaga E1,SC58, T.I.706 and Chaoxiankangjin.