Comparison Among Different Methods Of Molecular Markers And Preliminary Construction Of Molecular Genetic Map In Ramie [Boehmeria Nivea (L.) Gaud.]

Ramie [Boehmeria nivea (L.) Gaud.], called "China grass", originated in China. Ramie is a kind ofratoon perennial herbs which belongs to nettle boehmeria. China has a long history to cultivate and useramie. Ramie with high quality bast fiber is a significant raw material for the textile industry. Itplays an indispensable role in national economy for its unique characteristic and usage. Ramieplanting area and total output in China take up more than90%of the world. It is an importantexport product of China.Restriction site amplified polymorphism (RSAP) is one of new molecular marker techniques. Inorder to identify the feasibility of RSAP for the utilization on ramie, restricted site of amplifiedpolymorphic (RSAP)-PCR reaction system was optimized at first and the result showed as following:Taq DNA polymerase1U, dNTPs0.3mmol/L, primer0.25μ mol/L, DNA concentration10ng.Amplification products were separated on6%denaturing polyacrylamide gel8%, and colored aftersilver staining.Then, three molecular markers-RSAP, SRAP and SSR were used to cluster16Ramie germplasm.The result showed that each pair of primers could provide polymorphic sites and the site number wasSRAP>RSAP>>SSR. Both results clustered based on SRAP and RSAP showed high consistency withthat clustering based on combination of SRAP, RSAP and SSR, and the highly significant correlationcoefficients were given. However, results of clustering based on SSR marker were quite different fromthe results based on combined markers. The rank order of similarities between the clustering resultsbased on the molecular marker and phenotype was SRAP+RSAP+SSR>SRAP>RSAP>>SSR. For thestudy of genetic relationship among ramie germplasm, the efficiency of SRAP marker was slightlyhigher than that of RSAP marker, but that of SSR was low. Based on RSAP marker could efficientlydisplay the polymorphism and genetic relationship among ramie varieties. Using the combined markersof RSAP&SRAP&SSR could be to reveal the genetic relationship of germplasm. RSAP method withoutrestriction enzyme is easier than markers based on restricted sites, which has the characteristics ofmedium yield, stability and reliability, and wider applicability, and it is feasible for the utilization oframie.Using JoinMap3.0software to analysis352polymorphism markers based on SSR, RSAP andSRAP marker, a piece of ramie genetic map contains34chain groups was acquired. The map containedaltogether103markers, which had55RSAP markers,40SSR markers and8SRAP markers. The mapcovered the total length of1089.0cM, the average interval distance between markers was10.7cM, thelargest interval distance was50.9cM, the smallest distance was0.8cM. Number of markers in eachlinkage group varied from2to17.4linkage groups had17markers,8markers,6markers and5makersrespectively, two linkage groups had4markers, but also there were3markers in three linkage groups,and25doublets, the average number makers in each linkage group was3.0.