Analysis On Breeding Potential Of Partial Introduced Cigar Germplasms

Cigar belongs to a type of tobacco.At present,the development of domestic cigar has attracted much attention of related industries,and the lack of fine cigar materials has become one of the key factors limiting the rapid development of cigar,therefore,it is one of the effective ways to alleviate this contradiction to introduce foreign cigar germplasm resources in high-yield areas,to dig and create high-quality cigar germplasm.In this study,5 Cuba tobacco germplasms were hybridized with Cuba,Slovenian,Norwegian and Indonesian tobacco germplasms,and 20 hybrid combinations were allocated according to incomplete diallel analysis(NCII),in addition,the genetic distance of the parents of introduced cigar was determined by using domestic main varieties Dexue 1 and Dexue 3 as controls,a systematic analysis was made on the significant performance,combining ability,genetic effect,double plot based on combining ability analysis and heterosis of imported cigar,to evaluate its utilization value in growth period,plant type traits,leaf agronomic traits and quality traits.The main findings are as follows:1.The detection results using 34 pairs of SSR primers showed that the genetic distance of the parent materials of the tested combination ranged from 0.326 to 0.506,and the average genetic distance was 0.411.Among them,the genetic distance greater than or equal to 0.5 included Cuba 4 and Norway 1,Cuba 1 and Norway 1,the closest genetic relationship is Indonesia 1 and Cuba 4,which is 0.326.The cluster diagram shows that the parental material and the control variety are divided into 3 groups,Type I populations include Slovenian 1,Cuba 9 and Norway 1;Type II populations are two control varieties,Dexue 1 and Dexue 3;Type III populations include Indonesia 1,Cuba 1,Cuba 4,Cuba 5,Cuba 6 and Cuba2.Among the tested traits,except the leaf uniformity in the agronomic traits,which did not reach significant differences,other tested traits reached a significant or extremely significant level,indicating that the different genotypes of the tested cigar materials had higher plant height and pitch.There were real genetic differences in important traits such as average leaf thickness,growth period,and total nitrogen.3.According to the results of genetic effect and heritability,plant height,waist and leaf length and each growth period are mainly affected by the additive effect of parental genes,and the heritability of these traits is greater than 50%,which is conducive to direct selection in early generations;stem circumference,number of effective leaves,branch uniformity,total nitrogen,total plant alkaloids,starch and total sugar were significantly affected by the additive effect and non-additive effect of the parental genes,and the pitch,lumbar leaf width,branch number,leaf thickness,branch thickness and reduction Sugar is greatly affected by the non-additive effect of the genotypes of both parents,and their narrow-sense heritability is less than 50%,so selection should be made in the middle and high generations.The results of genetic correlation of various traits showed that most agronomic traits were positively correlated,and some of the traits had significant differences in correlation coefficients.In addition,there were negative significant correlations between waist leaf length and leaf evenness,waist leaf width and leaf evenness,and branch thickness.As for the correlation of chemical components,except that all initial chemical components were negatively correlated with starch,and total nitrogen was negatively correlated with total plant alkaloids,all other initial chemical components showed positive correlation.The positive correlation coefficient of sugar reached a significant or extremely significant level.It can be seen that there are obvious differences in the performance of genetic correlation between different traits.Therefore,the influence between traits should be fully considered in breeding,and the chain reaction of traits should be used correctly to improve the breeding efficiency.4.From the results of general combining ability effect analysis,it can be seen that the GCA effect values of different imported cigar germplasms on the same trait were significantly different,and the same external cigar germplasm also showed differences in different traits,and there was no phenomenon that GCA showed positive or negative effects on all traits.The parent materials with obvious utilization value for the comprehensive performance of each trait are Indonesia 1 and Cuba 4.Among them,Indonesia No.1 has obvious potential in improving plant height and effective leaf number,with moderate leaf area,leaf thickness and branch vein number GCA effect value,it is negative and has reached a very significant level,and the total plant alkali and starch content is low,the total nitrogen,total sugar and reducing sugar content is rich,and the growth period is short;Cuba 4 has obvious agronomic traits such as plant height and pitch.positive potential,the total plant alkali content was significantly lower than that of other parents,the sugar content was relatively rich,and the growth period was suitable.In addition,other parents have the potential to improve one or more important traits in one or more important traits,and the corresponding parents can be rationally utilized according to different breeding goals.By comparing the SCA effects of the important characters of the combinations,Cuba 6 and Slovenia 1,Cuba 4 and Norway 1,Cuba 7 and Norway 1 showed better SCA positive or negative effects on agronomic and chemical characters,which can be used to improve the characters of cigar tobacco germplasm.5.According to the results of over-standard dominance,the heterosis of plant height,effective leaf number and foliar traits of the tested cigar germplasm was widespread,indicating that the utilization of heterosis is beneficial to improve the various important traits of cigar germplasm.Among the tested combinations,Cuba 4 and Norway 1,Cuba 7 and Indonesia 1 had better comprehensive performance than other tested combinations in terms of agronomic traits,initial chemical composition,growth period and botanical traits,and the genetic The relatively large distances were 0.506 and 0.418,respectively,suggesting that it may have better breeding potential in production.