Genetic Diversity Analysis Of Pepper Germplasms Using Morphology And SSR Markers

Peppers(Capsicum spp.)play an important role in the world on vegetables.They can be used in a lot ways in our daily life.In this study,26 botanical characters were investigated.22 pairs of polymorphic primers were selected from 152 pairs of primers which were designed according to the genome sequence.They were used to analyse the diversity of the peppers.Then genetic relationship of 34 pod peppers were analysed by them.At last,the identification on Phytophthora of peppers were got.This study was helpful to the further research of peppers.1.Pepper germplasm are the important basis of pepper breeding.The findind of key germplasm resources can raise tremendous progress in variety breeding.The research of pepper grnetic diversity not only contributed to the collection and management of germplasm and provide convenience for scientific communication,but also benefited to the conducting of the research of core collection.In order to investigating genetic diversity of agronomic characters of the 271 peppers,which were saved in the laboratory,principal component analysis,correlation analysis and cluster anaiysis were analysed.The result showed that leaf length had the highest genetic diversity index and fruit surface gloss had the lowest genetic diversity index;The variation coefficient of the Single fruit weight was the maximal and the minimum genetic diversity index was branching pattern;Though the correlation analysis of each characteristic among varieties,8 principal component were selected and the accumulative contribution rate of the eight principal components accounted for 69.99%;According to genetic difference of each characteristic among varieties,the 271 accessions could be classified into 5 categories by cluster analysis;2.Polymorphism analysis of SSR markers.In order to further explore the pod peppers,genetic relationships,providing reliable theoretical foundations for the protection of germplasm resources and the breeding of new varieties.In this research,the genetic diversity of 271 peppers were analyzed by using 22 pairs of SSR markers with polymorphism and repeatability,which is distributed among 12 pairs of the pepper,schromosomes.59 polymorphic alleles were obtained,the mean value of polymorphism information conten(PIC)is 0.38,The mean value of effective allele number(Ne),observed heterozygosity(Ho),expected heterozygosity(He),Shannon-Weaver index(I),were 1.89,0.12,0.42,0.68,showed that peppers genetic information is not very rich.Cluster analysis with UPGMA method revealed that,when the genetic similarity coefficient was 0.57,the populations of 271 peppers could be divided into 5groups.3.In this research,the genetic diversity of 34 pod peppers were analyzed by using 21 pairs of SSR markers with polymorphism and repeatability,59 polymorphic alleles were obtained,the mean value of polymorphism information content(PIC)is 0.37,The mean value of effective allele number(Ne),observed heterozygosity(Ho),expected heterozygosity(He),Shannon-Weaver index(I),were 1.90,0.20,0.44,0.72,showed that pod pepper genetic information is not very rich.Cluster analysis with UPGMA method revealed,when the genetic similarity coefficient was 0.69,the populations of 34 Capsicum frutescens could be divided into 6groups.4.The indentification of phytophthora capsici resistance.7 high resistant peppers were selected.The disease index was between 0.00-10.00,the mean value was 6.27.60 risitant peppers were selected.The disease index was between11.43-30.00,the mean value was 23.65.133 medium resistangt peppers were selected.The disease index was between 30.48-50.00,the mean value was 40.21.62 susceptible peppers were selected.The disease index was between50.59-80.00,the mean value was 59.73.