| In the polyploid series, triploid is considered the best vegetative growth, and has obvious heterosis. Triploid cell volume increase caused great of morphological traits. As a result of meiotic disorders caused by reduced fertility,The triploid become the new target to fruit breeding and forest tree breeding..Triploid hybrid or selfing is a favorable way to obtain the aneuploidy material. The experiment applied Start condon targeted polymorphism(SCoT) technique to analysis the genetic diversity, and used methylation sensitive amplified polymorphism (MSAP) technique to anaysis DNA methylation level and heredity patterns of natural triploid loquat 'H324"and her seedling progeny as well as'da wu xing'(2x) and natural triploid loquat'G320'hybrids. The test provides a theoretical basis for triploid loquats on exploitation and ploidy breeding. It has an important reference value for the research of loquat and even plant on triploid genetic variation discipline. The primary results were as follows:The genetic diversity of 12 seedling progeny H324 from natural triploid loquat were studied by SCoT marker and morphological traits. The average coefficient of variation and Shannon-weave index were 32.63%(ranged between 16.20% and44.80%) and 1.92 (ranged between 1.47 and 2.24) respectively, A total number of 71 bands were amplified using 8 of 36 primers, among which 42 were polymorphic, the polymorphism ratio was 59.2%. The Jaccard genetic similarity coefficients among the accessions were calculated with NTSYS-2.1 software and the values were between 0.84 and 0.97. The cluster analysis of 12 seedling progeny 'H324' from natural triploid loquat conducted by using 8 of polymorphic SCoT primers and 7 Phenotype traits. The consequences of MSAP suggested that the total methylation ratio of natural triploid loquat"H324' and her seedling progeny genome are between 7.4% to 19.9%, The Fully methylated ratio are between 3.7% to 13%. The Hemi-methylated sites are between 1.7% to 7.9%. In all,5227 fragments were amplified using 6 pairs of selective primers, showed 544 fully methylated fragments and 222 Hemi-methylated fragments in 766 methylated fragments.The genetic diversity of'da wu xing'(2x) and natural triploid loquat 'G320' hybrids were studied by SCoT marker and morphological traits. The average coefficient of variation and Shannon-weave index were 31.94%(ranged between 17.81% and 40.48%) and 1.91 (ranged between 1.64 and 2.18) respectively, A total number of 68 bands were amplified using 8 of 36 primers, among which 49 were polymorphic, the polymorphism ratio was 72.1%. The Jaccard genetic similarity coefficients among the accessions were calculated with NTSYS-2.1 software and the values were between 0.74 and 0.95. The cluster analysis of "da wu xing'(2x) and natural triploid loquat'G320' hybrids conducted by using 8 of polymorphic SCoT primers and 7 Phenotype traits. The consequences of MSAP suggested that the total methylation ratio of 'da wu xing'(2x) and natural triploid loquat 'G320' hybrids genome are between 13.4% to 20.6%. The Fully methylated ratio are between 10.2% to 15.6%. The Hemi-methylated sites are between 2.1% to 6.7%. In all, 2027 fragments were amplified using 4 pairs of selective primers, showed 265 fully methylated fragments and 79 hemi-methylated fragments in 344 methylated fragments.Comprehensive results of this study, we believed there was no significant correlation the two cluster analysis. However, few individual plants were divided into single group. The natural triploid loquat DNA methylation level and heredity patterns was changed in selfing and hybrid. The results showed that these progeny from natural triploid loquat,there was greater genetic variation, with a wealth of genetic diversity, genetic breeding material with a loquat potential value.
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