Genetic Analysis And QTL Mapping On Leaf Main Characters Of Cigar Wrapper

Cigar wrapper leaves are the most important raw material in cigars and its leaf main characters determine the quality of the cigar.Therefore,clarifying the genetic law of main characters of cigar v leaves,is conducive to improving the cigar quality from the perspective of genetic breeding.A F₂ and F₃mapping population is constructed through the cross between foreign Beinhart1000-1 and local“Hefeng babayan”,we used the"main+polygene"model to analyse of genetic effects,and constructed genetic maps by simplified genome sequencing and detect QTL of corresponding traits.The main results are as fellows:1.Genetic analysis of the main characters of the Cigar wrapperThrough four generations of joint separation analysis methods,we found that the genetic heritability of foliar fold was 42.70%and 57.71%respectively at the rosette stage and budding stage.The heritability of leaf thickness was 64.44%and 50.62%respectively at the budding stage and the stage of central flowering.the inheritance of lateral vein diameter was 69.47%at the rosette stage,1.75%at budding stage and 32.52%at the stage of central flower,the genetic heritability of the angle between main and lateral vein was 90.93%and 42.55%respectively at the budding stage and the stage of central flowering.It was concluded that the genetic effect of the same trait was different at different stages,and genetic models and interaction effects showed differences at different developmental stages,4 traits are mainly affected by genetic factors.2.Construction of genetic map of cigarWe analyzed 151 individuals of F_2:3 through the cross between Beinhart1000-1 and“Hefeng babayan”by simplified genome sequencing,we developed 94818 points with polymorphism among parents,then screened child markers after typing,A total of 1196 valid markers entered the chain analysis.We constructed the inheritance map of with Joinmap4.0 software,removed badly unreachable markings,we got 1036 SNP markers in the end,and built 24 linkage groups.The genetic map covers 24chromosomes of the tobacco genome,the length of genetic map is 3848.58cM,there are 43.2 SNP markers at per linkage group averagely,there is one SNP marker averagely per 3.71cM.3.QTL of the main characters of Cigar wrapperWe conducted QTL analysis with trait phenotypic data from different periods,A total of 69 QTLs related to four traits were detected,Among them,there are 22 QTLs related to foliar fold,14 QTLs related to leaf thickness,21 QTLs related to lateral vein diameter,12 QTLs related to angle between main and lateral vein.All QTLs are mainly distributed on all other linkage groups except the 16 linkage group,which explains 1.41%-83.7%.There are QTLs related to each trait that can be detected in multiple periods.There was a major QTL about foliar fold located in 66.51cM on chr14 linkage,which was detected at F_2:3 budding stage and central flowering stage,and explained 6.25%and 4.55%of phenotypic variation;There was a major QTL about leaf thickness located in 37.91cM on chr22 linkage,which was detected at F₂ and F_2:3budding stage,and explained 14.71%and 22.11%of phenotypic variation;There was a major QTL about lateral vein diameter located in 63.11cM on chr18 linkage,which was detected at F₂ rosette stage and central flowering stage,and explained 20.53%and 10.66%of phenotypic variation;There was a major QTL about angle between main and lateral vein located in 175.61cM loci on chr18 linkage,which was detected at F_2:3 budding stage and central flowering stage,and explained 4.99%and 7.88%of phenotypic variation.These QTLs have stable genetic effects,priority as molecular marker-assisted selection study.