Study On Betula Platyphylla Long Fiber Trait By SSR Marker Technology

The Betula platyphylla is pioneer and excellent short cycle broad-leaved pulp tree innortheast and inner-Mongolia region.Because the fiber length is the main factor for paperquality, the hereinafter study was done in this paper to accelerate the progress of new variety forlong fiber pulp B.platyphylla.After measurement and analysis fiber length trait (FLT) and distributing trait of 538individuals from nature B.platyphyIla population in maoershan experiment forestry centre and200 individuals from nature B.platyphylla population in harerbin experiment forestry centre,the FLT is the model quantity trait suit to study using marker analysis,moreover the 100individuals from maoershan and 40 from harerbin were selected to be analyzed by moleculemarker.The orthogonal design was used to optimize SSR-PCR amplification system onB.platyphylla.A most suitable SSR-PCR system for B.platyphylla was established,it was 20μLreaction system which contained 150ng DNA template,3 mmol/L Mg²⁺,0.5U Taq DNApolymerase,0.5mmol/L dNTP,0.4μmol/L Primer.SSR-PCR reaction system of birch wasperformed.Initial denaturation was for 5min at 94℃,follow by 35 cycles of denaturation for30S at 94℃,annealing for 30S at 59.5℃, extension for 30S at 72℃and a final 5 min extensionat 72℃,conservation at 4℃.By using bioinformatics,through the sequential analysis of 2548 ESTs sequences ofBetula pendula Roth. in NCBI,the results indicated that 307 SSRs distributed in 260 ESTs weremined out from 2548 ESTs sequences account for 10.20% of the whole EST sequences,thefrequency of SSR was 12.05%.By using SSR Primer and Primer3 software to discoverynortheast birch SSR primers in 260 EST sequences contained SSR sequences. The resultindicated that: Primer3 designed 176 pairs of SSR primer, there were 104 primers hadampliation,the proportion of primer successfully amplified in B.platyphylla was 59.09%,therewere 27 pairs of primers have polymorphism, the proportion was 25.96%.SSR Primer designed100 pairs of primer, there were 37 pairs of primers have ampliation,the proportion of primersuccessfully amplified in B.platyphylla was only 37.00%,there were 18 pairs of primers havepolymorphism.After Multiple-factor Regression analysis the SSR molecular and fiber length,the 4 stripSSR molecular having notable correlation with fiber length were received.By using SSRprimers correspondenced with the 4 strip SSR moleculars to extend the validate colony, theresult indicated that:4 pairs of long fiber SSR primers could identify 60.00% averagely.PB15could identify as high as 75.00% long fiber individuals,which was the maximal distinguishing ability among 4 strip SSR moleculars.