| Hemp（Cannabis sativa L.）has high economic value.In addition to traditional fiber and seed use,the cannabidiol（CBD）mainly in flower heads and leaves also has great medicinal importance.It is extensively used in food,daily chemical,and pharmaceutical fields.CBD is an important indicator of cannabis breeding,and it is of considerable significance to locate the QTLs that affects the CBD content of cannabis.In this study,SSR molecular marker was used to identify the F2 population that established from the high CBD content material’RO’and the low CBD content material’Y8’,andconstruct the genetic linkage map of"RO×Y8"combined with the CBD content of single plant of the F2 population,and carried out preliminary positioning of the QTLs related to the CBD content.This work aimed at providing support to cultivation and genetic improvementof hemp.The main findings are as follows:1.Based on the published cannabis transcriptome sequencing information,a total of 39,663 Unigenes sequences were obtained with a total length of 66.26Mb.The obtained Unigenes sequences were searched for SSR sites,and a total of 7047sequences were detected containing 9279 SSR sites,mainly trinucleotide repeats and the least tetranucleotide repeats.In terms of motif types,the frequency of repeating AG/CT with dinucleotides is the highest.2.The CBD content of 144 female individual plants of the"RO×Y8"hybrid F2population was analyzed by high performance liquid chromatography.The CBD content of parent RO was 5.59%,and that of Y8 was 1.53%.The average CBD content in the F2population was 2.10%,which was between the two parents.The variation range of CBD content was 0.11%-4.52%,and the coefficient of variation was 44.59%.The content of CBD in the F2 population showed continuous variation characteristics,so it was inferred that the CBD content of cannabis was a quantitative trait controlled by polygenes and was suitable for QTL mapping.3.Among the 480 pairs of SSR primers designed and synthesized,361 pairs of primers showed amplification products,the amplification efficiency was 75.21%,and there were 103 pairs of polymorphic primers,and the polymorphism rate was 28.53%.Using the 144 female individual plants of the"RO×Y8"F2 segregating population as the mapping population,the brand-new developed EST-SSR markers were used to genotype the population,and a map containing 71 SSR markers covering 9 linkages was constructed.Full-length 1260.69c M,the average map distance between markers is17.76c M genetic linkage map.4.QTL mapping of CBD content in the"RO×Y8"F2 populationconsisting of 144female plants was carried out,and a total of 2 QTLs related to CBD content were detected,which were located on chromosome 2 and chromosome 9,named qcbd2-1 and qcbd9-1.The LOD value is 3.32-3.82,and the phenotypic contribution rate is 3.35%-12.72%.The additive effect of qcbd2-1 on chromosome 2 was positive,and the synergistic gene came from the maternal RO.The additive effect of qcbd9-1 on chromosome 9 was negative,and the synergistic gene came from the paternal Y8. |
