Genetic Diversity Analysis And Construction Of SSR Fingerprints Of Fig Germplasm

Fig(Ficus carica L.),with rich nutritional value and medicinal value fruit,has strong adaptability to various environment and is easy to cultivate.Therefore,the fig industry has high development potential.Figs are not native to our country.In the process of long-term introduction of varieties from abroad and cultivar exchange,the phenomenon of homonyms or homonyms may occur due to differences in naming the cultivars.It is difficult to conduct accurate germplasm identification only by phenotypic traits.Therefore,the development of stable and reliable molecular markers for fig germplasm diversity analysis,fingerprint map construction and other studies are of great significance for the identification,selection,preservation and industrial development of fig germplasm.The fig germplasm of Youtan Fig Research Institute of Jiaxiang County,Shandong Province was used as the research material.This paper observed and counted the phenotypic traits of functional leaves,the color of the peel and the color of the ripe fruit,which was employed to cluster and analyze fig germplasm.At the same time,the development of a stable SSR molecular marker system was based on fig genomic data;and then the diversity analysis and fingerprint mapping were performed using the 23 pairs of primers.The specific results are as follows:(1)Peel color and flesh color have high discriminatory ability among 8 phenotypic traits.Among them,the color of peel has the largest proportion of yellow at 14.75%;the color of pulp has the largest proportion of red at 27.05%.The 122 fig germplasms were analyzed by UPGMA clustering based on morphological traits,which can be divided into four categories.This classification reflects the difference in phenotypic traits.(2)Primer 3 software was used to design 5173 primers with three nucleotide motifs based on the fig-based genome.Then 384 pairs of primers uniformly on the genome were selected for PCR amplification and capillary electrophoresis detection.Finally,23 pairs of primers(PIC?0.4,good banding and stable)were chose from 23 different scaffolds of the fig genome.(3)Analysis of 125 fig germplasm by 23 pairs of primers,the average value of observed heterozygosity is 0.545,the average value of expected heterozygosity is 0.562,the average number of average alleles is 4.435,the average number of effective alleles is 2.378,the average value of Shannon information index is 1.001,the range of polymorphism information content is 0.291 ~ 0.655,and the average value is 0.497.(4)UPGMA cluster analysis and principal component analysis of 125 fig germplasms were compared for SSR markers.The results show that the classification results are basically consistent.And the SSR fingerprints were constructed on 61 distinguishable fig germplasms.According to Mantel test,the correlation between the distance matrix based on SSR markers and phenotypic traits is weak(r=0.076).