Construction Of Core SNP Marker Set And SNP Fingerprint Library Of Important Varieties In Bottle Gourd

Bottle gourd is one of the most important cucurbit vegetables in south China.In recent years,with the promotion of germplasm resources consolidation and protection of bottle gourd,the number of cultivated varieties has increased year by year.Following this,there are also some problems,such as foreign bodies with the same name,different names and intellectual property disputes.Therefore,it is urgent to establish an accurate,simple and rapid method for identifying and detecting the purity of bottle gourd resources or varieties,and to construct the core germplasm population of bottle gourd,so as to solve the problems of resource redundancy and inconvenient conservation management caused by the accumulation of a large number of germplasm materials.Nowadays,DNA molecular markers provide new options for crop genetic diversity research and variety identification.However,there is no comprehensive and systematic identification and evaluation of germplasm resources and important varieties of bottle gourd,and there is no report on core germplasm of bottle gourd.In this study completed the historic fully sequenced genome sequencing and some important germplasm melon,on the basis of further use of SNP marker with high flux classification technology to build a set of broadly representative at the core of SNP tag set,the SNP marker set is following the construction of core germplasm resources and resources or cultivar identification and purity testing,etc.The main research results are as follows:1.Screening and detection of high quality SNPS.Based on the genome of "Hangzhou" bottle gourd sequenced and assembled by our research team and Gourd Base(http://www.gourdbase.cn/),the first multi omics database platform for bottle gourd at home and abroad,a total of 1100 SNPs uniformly covering the chromosome of bottle gourd were selected.Then 220 polymorphic loci were screened from 12 important cultivars with different phenotypes and geographical origin.Primers were designed to transform 220 SNPs with high polymorphism into KASP markers,and 200 SNPs successfully transformed into KASP markers,namely pre-core SNP markers,were developed.A total of 186 KASP markers with good polymorphism were obtained from 22 known germplasm materials with large genetic distance after detection of pre-core SNP markers,and 93 high-quality SNP loci with good typing results were screened out according to high-throughput typing results.2.Development of SNP core markers and genetic structure analysis of bottle gourd population.Genotypes of 206 bottle gourd germplasm were detected by 93 high-quality SNPs,and saturation analysis was carried out according to the polymorphic information,minimum allele frequency,observed heterozygosity and deletion rate of the materials.Finally,the optimal number of SNPs was determined as 22,namely the core SNP marker set.Then 22 core markers and 93 high-quality markers were used to analyze the genetic structure of 206 samples.The results showed that the core marker set composed of 22 core SNP markers was highly representative in the whole bottle gourd population.3.The core germplasm population of bottle gourd was constructed.A representative core germplasm population of 102 bottle gourd germplasm was constructed by integrating 206 bottle gourd germplasm materials and 22 core SNP marker sets with Core Hunter software.Based on the calculation of genetic distance and genetic diversity index,PCA analysis showed that the core germplasm population was highly consistent with the original germplasm,and the allele coverage reached 100%.Considering the size,phenotype and geographical distribution of the core germplasm,48 germplasm were added to form the core germplasm population of bottle gourd containing 150 materials.4.The methods of variety identification and purity detection were constructed.Based on the core SNP marker set,SNP fingerprints of 206 important bottle gourd germplasm and cultivars of germplasm materials were constructed,and bar code and quick response code were converted using barcode online generator(http://barcode.tec-it.com/barcode-generator.aspx).By using the fingerprint library,the method of variety identification and purity detection was further established to realize the rapid identification of parentage relationship of bottle gourd.The results of this study are beneficial to germplasm resources management and utilization,variety protection and rights protection.