Genetic Linkage Map Construction And QTL Mapping Of Liriodendron

Genetic analysis was performed in a population composed of 196F1 individuals derived from a interspecies cross of Liriodendron tulipifera and L.chinense（BM×S）.AFLP and SSR molecular markers were used to construct genetic linkage maps for both parents.A new mapping software called High Map were used to construct the linkage maps.QTL detection of some important traits were also performed based on the maps.The main conclusions are as follows:（1）AFLP markers were used for the map construction of Liriodendron for the first time,meanwhile,a AFLP-STR system was established,and the AFLP pre-amplification and selective amplification reaction system were optimized under the following steps:a.The AFLP pre-amplification was performed with a 25μL PCR mix which consisted of 3.0μL DNA,0.2mmol/L d NTP,1.5mmol/L Mg Cl₂,40n M E00primer,240n M M+C primer and 0.04U/μL r Taq.b.The selective restriction fragment amplification was performed with a 15μL PCR mix which consisted of 3.0μL DNA,0.2mmol/L d NTP,2.0mmol/L Mg Cl₂,0.2μmol/L E-NN primer,0.6μmol/L M-NNN primer and 0.06U/μL r Taq.This technology can provide a large number of stable and reliable molecular genetic markers in a short period of time,which greatly improve the detection polymorphism and retain the genetic information to a great extent.（2）An interspecific F₁population of BM×S with 196 progenies were used as the mapping population.A genetic map of 1914.34c M,consisting of 12 linkage groups and 389 markers was constructed for the female parent BM,377 AFLP markers and 12 SSR markers were included.The genetic map of male parent S had a total map distance of 1326.36c M and contained 10 linkage groups and 436 markers,it were included 428 AFLP markers and 8 SSR markers.The monomer source and linkage relationship of the markers were also evaluated by the High Map software.（3）The QTL analysis of the growth traits（tree height,DBH）,mature leaf traits and stem traits（branch number and branch angle）were performed with the CIM method of the R/qtl software.A total of 23 QTL were detected,among which,H1,H2-2,H3-2,H4-2,with LOD values greater than 3.5,can be treated as the same QTL,and may be deemed to be the main QTL controlling tree height.Besides,3 QTLs controlling leaf length and 9 QTLs controlling the narrowest width of leaf were also detected.