Genetic Diversity Analysis And Verticillium Wilt Resistance Of Eggplant Germplasm Resources

Eggplant?Solanum melongena L.?has rich nutrients and strong health care function.It is one of the most important vegetables in the world,and has a large and wide planting area in China.In order to provide reference values for innovation and variety selection of eggplant germplasm resources,we analyzed the genetic diversity and population structure of eggplant germplasm resources,enriched their narrow genetic background to promote eggplant improvement.In this study,genetic diversity of 135 eggplant germplasm resources were analyzed based on 21phenotypic traits.Disease resistance was evaluated by artificial inoculation with Verticillium dahliae in seedling stage;The SNP polymorphism markers of eggplant chloroplast and nuclear genome were screened by PCR amplification,agarose gel electrophoresis and sanger dideoxy chain termination method.The relationship and genetic diversity of 70 eggplant materials containing different species were analyzed by the final DNA fragment.The main results are as follows:1.The agronomic traits of the tested germplasm resources had abundant genetic diversity.The variation coefficients of 21 phenotypic traits ranged from 15.71%to89.86%,and the genetic diversity index ranged from 0.322 to 2.135.Principal component analysis of 21 phenotypic traits was attributed to 6 main factors such as fruit shape factor,color factor,fruit weight factor,growth potential factor,plant type factor and fruit commercial factor.The cumulative contribution rate of 6 main factors was 72.84%.The clustering analysis divided the tested materials into 4groups which included group i?cultivated varieties and S.incanum L.?,group ii?wild relatives of germplasms?,group iii?large fruit-type of cultivated varieties?and group iv?long strip purple germplasms?.2.Resistance evaluation of Verticillium wilt showed that the disease index of the tested materials ranged from 5.00 to 100.00,and the resistance has obvious difference between different species.Meanwhile,we got nine resistant materials,six medium-resistant materials and eleven tolerant materials,which accounted for19.26%of the tested materials.Among 11 resistant materials,only three were cultivated varieties,and the rest were wild relatives,which indicated that wild relatives have strong resistance to Verticillium wilt.The resistant materials are distributed at home and abroad.And the domestic ones are mainly concentrated in the south,especially in the Yunnan germplasm.3.Eleven pairs of polymorphic primers covering 10 chromosomes of eggplant and one pair of universal chloroplast identification primers matK in flowering plants were used to analyze the genetic diversity and population structure of the tested eggplant germplasms:1892 mutation sites?464 single mutation sites,1131minimal information sites and 297 insertions/deletions?were detected.The nuclear gene fragments that the nucleotide polymorphism Pi,the Tajima's D values of neutral test,the diversity H_d of average haplotypes were respectively 2.293×10^-2,-1.99704?P<0.05?,0.547;The germplasm ranges of genetic distance?K2P?from 0to 0.1426,with an average of 0.0234.Among them,between S.torvum S.and S.indicum L.germplasm is 0.0533 of genetic distance,between S.incanum L.and S.melongena L.germplasm is 0.0008 of genetic distance;NJ clustering,nuclear-based haplotype pedigree relationship and genetic structure background analysis can divide the tested germplasms into four clusters.The above results indicated that the genetic diversity of the tested germplasm species was high,and the level of genetic diversity within the species is lower than hat of the interspecific species.At the same time,we screened some polymorphic nuclear gene fragments related to anthocyanin synthesis,growth and development and flowering regulation?FSB1,DFR,ccs52A,NAC,NAM,SP5G,FLC,Sm669,Sm12216?,and DNA barcode of Solanum species?the chloroplast gene matK fragment and 11 nuclear gene fragments?.The clustering results of morphological traits and DNA sequences indicated that classsifications were related to eggplant genetic relationship and fruit traits.The results of this study which provided an important theoretical basis for finding excellent genes,germplasm innovation and breeding of new varieties of eggplant germplasm resources.