Evaluation On Salt Tolerance And Research On Molecular Markers Of Elytrigia Repens Of Xinjiang

Elytrigia repens had high nutrition value,drought resistance、cold resistance、disease resistance、strong spreading ability,which was worth exploiting as salt tolerant plant. Xinjiang was a main distributing area of Elytrigia repens in China and there was abundant wild Elytrigia repens resource but salt resistance study was seldom carried out,the salt tolerant threshold of seed germination stage and seedling stage were unclear and molecular markers closely linked to salt tolerance was lack.The research identified the salt tolerant threshold of Elytrigia repens in xinjiang during seed germination stage and seedling stage with Na Cl simulating salt stress and selected the RAPD、SRAP molecular markers closely linked to salt tolerance with BSA method in order to lay the foundation of Elytrigia repens’ s breeding work in the future. The test results were as follows:(1) 12 Elytrigia repens germplasm resources as materials,The germination experiment during seed germination stage was carried out under 0.0%、0.4%、0.8%、1.2%、1.6%、2.0%、2.4%、2.8% NaCl stress,germination rates、germination indices、radical length、plumule length、fresh weight were measured and the salt sensitive indicators were selected and the salt tolerant threshold was determined. The results showed that plumule length and germination indices were more sensitive to salt stress in 5 germination index, it was respectively 0.93% 、0.96%.The membership function analysis showed that salt tolerance order of 12 Elytrigia repens were E17、E04、E16、E31、E25、E12、E42、E37、E27、E35、E19、E38.The salt toleranct materials were E04、E16、E17、E31、E25 and tolerance threshold were higher than 1.43%,salt sensitive material were E27、E35、E19、E37、E38 and tolerance threshold were lower than1.28%.(2) 9 Elytrigia repens germplasm resources were choosed as materials and salt resistance during seeding stage were carried out under 0.0%、0.5%、1.0%、1.5%、2.0%、2.5% NaCl salt stress,surival rates、above ground biomass、leaf chlorophyll index、electricity conductivity、green coverage rate、vertical growth rate were measured.salt sensitive indicators were selected and the salt tolerant threshold was determined.The results showed that green coverage rate and electrical conductivity were more sensitive to salt stress, it was respectively 1.43% 、 1.47%.The subordinate function analysis method showed that the membership function analysis showed that salt tolerance order of 9 Elytrigia repens were E06、E34、E27、E24、E43、E35、E23、E15、E08.The salt toleranct materials were E06、E34、E27、E24, tolerance threshold were higher than 1.69%, Salt sensitive materials were E23、E15、E08 and tolerance threshold were lower than 1.49%.(3) Orthogonal design was applied to optimizing SRAP-PCR system of Elytrigia repens,and 47 Elytrigia repens was amplificated with this systm.The results showed that the optimal system of SRAP-PCR Elytrigia repens was Mg2 + 1.75 mmol/L、primer 0.15 μmol/L、dNTPs 0.20 mmol/L、DNA 50 ng/20μL、Taq DNA polymerase 0.75U、2μL 10×PCR buffer in 20μL.The influence of various factors on this reaction system was Mg2+ = primer > Taq DNA Polymerase > dNTPs > DNA.The 62 SRAP primers were selected from 484 pairs of primers and 492 bands were amplificated,398 bands were polymorphic,percentage of polymorphic loci was 82.16%.(4) The salt resistant and salt sensitive matrrials of Elytrigia repens in seed germination stage and seedling stage were amplified by using 484 pairs of SRAP primers and 100 RAPD primers in DNA pools and through single plant verification,the molecular markers closely linked to salt tolerance of Elytrigia repens were selected.4 pairs of SRAP primers(Me4+Em4、Me5+Em8、Me9+Em6、Me13+Em7) and 2 RAPD primers(E-43、E-72)were closely linked to salt tolerance during seed germination stage; 1 pair SRAP primers(Me19+Em13) was closely linked to salt tolerance during seedling stage.