Study On The Drought Resistance And Genetic Diversity Of Arrhenatherum Elatius Germplasm By Issr Molecular Marker

With the method of simulating drought stress-water recovery in greenhouse, 8 drought resistant indexes, including the leaf relative water content (RWC), relative electrical conductivity(REC), free proline accumulation (Pro), soluble sugar content (SSC), superoxide dismutase(SOD) , malondialdehyde (MDA), survival rate(SR), root-shoot ratio(RSR) on the 0d(CK), 7th d,14th d,28th d,35th d,42th d under the water stress and the 7th d after rewatering, respectively, of 19 Arrhenatherum elatiusm germplasm materials at the seedling stage were measured and analyzed in order to assess comprehensively the drought resistance.(1) The leaf RWC of 19 germplasm decreased, the SSC, Pro and REC increased but the SOD and MDA increased with volatility while the drought stress days were increased. Seven days after rewatering, the RWC and Pro were restored to pristine level, but the SOD and MDA were not restored to the level before stress were exerted although they declined in varying degrees. Under the condition that the soil volumetric water content is 3% to 5%, although the leaves of the tested germplasm wilt and curl to some extent, it also can maintain a relatively stable trend.Among these, ZXY2005P-706,ZXY2005P-1086,ZXY2005P-1036,ZXY2005P-877 all maintain the 90% survival rate, showing a relatively strong drought resistance.The values of the eight indexes which has been treated under the condition of 42d of resistant drought stress, which has been analyzed by the Wared's method and Squared Euclidean distance cluster analysis, the results showed that three drought resistant classes including the higher drought resistance (including the germplasm of ZXY2005P-1021, ZXY2005P-619, ZXY2005P-853, ZXY2005P-1160, ZXY2005P-1319, ZXY2005P-901) , the medium drought resistance (including ZXY2005P-706, ZXY2005P-1086, ZXY2005P-1473, ZXY2005P-1296, ZXY2005P-1182, ZXY2005P-1036, ZXY2005P-877, ZXY2005P-837)and the weaker drought resistance (ZXY2005P-1514, ZXY2005P-969, ZXY2005P-1375, ZXY2005P-1362, ZXY2005P-1426) were classified . And the leaf RWC of 19 germplasm(2)The 11 Primes selected for use and detected a total of 152 bands,among whieh107 bands were Polymorphie. Materials aecessions ranged from 0.591一0.886.Abundan tgeneti ediversity among Arrhenatherum elatius L.The average Percentage of Polymorphic bands(PPB)was 68.9%,and the range of GS was from 0.4821 to 0.7411,which indicated a rich genetie diversity of P.juneea.Based on cluster analyses of the genetic eharacteristics,19 A. elatus could be divided into 3 grouPs according to the nearest Phylogenetic relationship.in most cases materials from the same region were in the same group thus showing a geographieal distribution of genetic diversity of the tested materials.