Genetic diversity analysis of 133 pellicle melon germplasm resources based on TP-M13-SSR molecular marker technology

【Objective】To analyze genetic diversity of pellicle melon germplasm resources from different provinces(regions)in China,so as to provide theoretical basis for collection,genetic improvement and efficient utilization of melon germplasm resources.【Method】133 samples of pellicle melon germplasms from different provinces(regions)in China were taken as materials. 12 pairs of SSR primers with high polymorphism were screened. Genetic diversity analysis of 133samples of pellicle melon germplasm materials was conducted through TP-M13-SSR molecular marker technology. Cluster analysis model was performed according to the Nei's genetic distance(D)and the genetic structure of population material was analyzed by the mixed model clustering method of Structure software.【Result】The number of alleles(Na)was54 after amplification of 133 samples of pellicle melon germplasm materials with 12 pairs of primers and the average Na per pair of primers was 4.5. The number of effective alleles(Ne)was 1.120-2.234,and the average was 1.533. Observed heterozygosity(Ho)was 0.023-0.466,with an average of 0.217. Expected heterozygosity(He)was 0.107-0.552,with an average of 0.319. The Shannon information index(I)ranged from 0.267-1.237 with an average of 0.642. Polymorphism information content(PIC)of sites ranged from 0.104-0.531,with an average of 0.295,indicating most sites were moderately polymorphic. According to cluster analysis,133 pellicle melon materials were divided into two groups. GroupⅠ consisted of 4 thick and thin skinned intermediate melon materials,and group Ⅱ consisted of 129 pellicle melon materials.According to results of population genetic structure analysis,when the K=4,△K peaked obviously,indicating that the 133sample shall be divided into 4 groups. Moreover,among 133 materials,the Q value of most materials was greater than 0.6.【Conclusion】The 12 pairs of primers used in this study are moderately polymorphic,and more molecular markers are needed to identify pellicle melon materials effectively. The genetic structure of the tested materials was relatively simple and of low genetic diversity,indicating identical materials with different names may exist. Exploration and utilization of germplasm resources with different genetic backgrounds and distant relationships should be strengthened.