| 34 varieties/lines with good stress resistance and 30 radiationhybrides with specificity were obtained from 318 series of Agrostis stolonifera L germplasm resources by combining field tests and molecule specific screening. Then the genetic diversity of 34 varieties/lines was analyzed using RAPD(Random Amplified Polymorphic DNA)method while the genetic diversity of 30 radiationhybrides created by mutation was analyzed using Sequence-related amplified polymorphism (SRAP). DNA fingerprint for 13 varieties/lines with good quality was constructed. These results lay the basis for the exploitation of Agrostis stolonifera L. new varieties.1.Genetic diversity of 34 varieties/lines analyzed by RAPD(Random Amplified Polymorphic DNA)method(1) A protocol which is efficient for Agrostis stolonifera L DNA isolation for its high yield (107.992～165.733 ng/μg.FW) and high DNA purity (OD260/OD280 of 1.706～1.873) was established (viz. improved CTAB method).(2) PCR reaction system was optimized by monofactorial experiments. The optimum components in 20μL reaction system were: Taq 1U, primer 0.5μM, DNA 40 ng, dNTPs 0.375 mM, 10×PCR buffer 2.0μL, MgCl2 2.5 mM, ddH2O 12.05μL.(3) According to the results of RAPD, 424 bands were generated using 47 primer and 288 among them were polymorphic, with a mean percentage of polymorphic bands (PPB) of 67.9%. Genetic diversity of the samples was expressed as Shannon-diversity index (SHDI) with a mean value (I) of 0.3862. The genetic similarity coefficient was 0.2414. The observed number of alleles (Na) and efficient number of alleles (Ne) was 2 and 1.3715 respectively. The genetic distance (GD) ranged from 0.0720 to 0.8986. The bred cultivars showed intermingled plant types and stress resistance. Meanwhile, the genetic diversity between them was narrow. These might be related to the disadvantages of rediationhybrids.2.Genetic diversity created by mutation of 164 radiationhybrids analyzed by Sequence-related amplified polymorphism (SRAP) method(1) By orthogonal experiments, the optimum reaction system for SRAP-PCR was established with following components in 25μL volume: 10×buffer 2.5μL, Mg2+ 1.25 mmol/L, dNTP 0.24 mmol/L, primer 0.20μmol/L, Taq 1U and DNA 50 ng. 32 primer pairs produced good band patterns were selected out of 72 primer pairs for SRAP- PCR.(2) 30 varieties with high specificity were selected out of 160 radiationhybrids for genetic diversity analysis. According to the results of SRAP, 419 fragments were generated using 25 primer pairs and 232 among them were polymorphic, with a mean PPB of 55.4%. Mean diversity index (I) and genetic diversity (He) was 0.4672 and 0.3040 respectively. The Na and Ne was 2 and 1.5011 respectively. The GD ranged from 0.0092 to 0.7793. The internal mutation rate of different radiationhybrids is (from low to high): Yuexuan No. 1, Yuexuan No.3 new lines, Yuexuan No. 2 new lines, indicating that there were more specific mutated varieties in Yuexuan No.2 radiationhybrids. Penncross with other radiationhybrids genetic similarity as follows (from high to low): Yuexuan No. 1, Yuexuan No. 2 new lines, Yuexuan No. 3 new lines, Yuexuan No. 1 from Penncross also judged .(3) According to the results of DNA finger print and genetic diversity analysis for 13 Agrostis stolonifera L. varieties/lines based on SRAP, 184 bands were generated and 131 fragments were polymorphic using 17 pairs of primers, with a mean PPB of 71%. DNA finger print using primer pairs F2R5 contained 39 polymorphic bands and 12 polymorphic loci with significant different band patterns. The mean GD ranged from 0.0285 to 0.7587. Among the 13 varieties/lines, GD between Yuexuan No.3 new lines and Yuexuan No.5 new lines was the smallest (0.0285) and that between Yuexuan No.1 and Yuexuan No.4 was the largest (0.7587). Yuexuan No.1 had the smallest GD to Penncross (0.4536).
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