Resistance Against Pythium Diseases And Genetic Polymorphism Of Different Poa Pratensis Cultivars

As an important cool-reason turf grass, poa pratensis L. was often infected lawn diseases when it is very hot and wet. So it is very significant to choose the high-resistance cultivar to plant lawn. In this study,45 accessions poa pratensis L. were used for resistance against Pythium diseases.18 high-resistance cultivars were chosen for ISSR based genetic diversity, and an orthogonal design was used to optimize a SRAP-PCR system with 4 factors at 3 levels plus the concentration of template DNA. The main results are as follows:1,These 45 cultivars were divided into 4 classes by the results of resistance experiment, that were HR, MR, MS, HS. HR included Park, Kentucky, Capton, Midnight, Nassau, Draglor, Colorado, Leopard; MR included Challenger, Barrister, Award, Blue bird, and so on; MS included Washington, Desting, Kelly, Kenblue, Merit, Sapphire, Jugera, Parada, Eclipse, and so on; HS included Sydsport, Danga, Balin, Reubens, Entensa, Trou, Huntsville, Argyle, Snow wolf, Fylking, Morsanskij.2,The genetic diversity of 18 cultivars was estimated by ISSR Marker,15 ISSR primers generated 126 bands, of which 104 were polymorphic,6.93 polymorphic bands number was obtained averagely. The polymorphic percentage was 82.54%.3,The Jaceard coefficient was calculated using NTSYS-PC software. The result showed that similarity coefficient of the 45 cultivar varied from 0.57 to 0.93.4,The fingerprinting data were further analyzed using UPGMA Cluster methods, which clustered the 18 cultivars into 4 main distinct groups. Park, Draglor, Kentucky, Midnight, Challenger, Kenblue, Award, Bluechip and Leopard were a class; Washington, Kelly, Desting and Merit were a class; Tory and Primd were a class; Huntsville, Argyle and Fylking were a class.5,An orthogonal design was used to optimize a SRAP-PCR system with 4 factors at 3 levels plus the concentration of template DNA. The optimized SRAP-PCR system for Poa pratensis L. was:2μL 10×PCR buffer,40ng template DNA, Mg2+ 1.75 mmol/L dNTP 220μmol/L, primer 0.25μmol/L, Taq DNA polymerase 1.0 U in a total of 20μL reaction solution.6,43 primer combinations were selected with the optimized system aming 100 primer combinations, then selected 6 of them to SRAP-PCR 4 cultivars, the results shown:6 primers generated 34 bands, of which 17 were polymorphic, the polymorphic percentage was 50%,2.8 polymorphic bands number was obtained averagely.