Analysis Of Genetic Diversity Of Different Quinoa Germplasm Resources Using SSR Molecular Markers

Quinoa（Chenopodium quinoa Willd.）is an annual dicotyledonous herbaceous plant,which originates in the Andes Mountains of South America.Quinoa,as a traditional food of the local people,is an important food in the Andes,and has been cultivated for more than 7,500 years.Quinoa germplasm is highly diverse.It can tolerant a series of abiotic stresses such as barren,drought,saline-alkali,frost,and biotic stresses such as diseases and insect pests.Quinoa has very high nutritional value and is the unique food identified by FAO that can meet the basic nutritional needs of human.Due to its excellent nutritional and functional properties,quinoa has quickly received widespread attention.At present,DNA molecular markers used in genetic research are diverse and have developed to the third generation.For example,the first generation of molecular markers with molecular hybridization as the core,including RFLP（Restriction Fragment Length Polymorphism）,DNA fingerprinting technology;PCR-based second-generation molecular markers,including RAPD（Random Amplified Polymorphic DNA）,SSR（Simple Sequence Repeats）,AFLP（Amplified Fragment Length Polymorphism）and STS（Sequence-tagged Site）;and some new molecular markers such as SNP（Single Nucleotide Polymorphisms）,EST（Sequence-tagged Site）and so on.As a second-generation molecular marker,SSR molecular markers have the advantages of simple operation,good reproducibility,high polymorphism,and strong specificity.The structural changes in DNA molecules can be directly detected and the essential differences in research materials are reflected using SSR molecular markers.Therefore,SSR marker has been widely used in the research fields of genetic diversity analysis,germplasm identification,DNA fingerprinting construction,gene mapping and molecular marker breeding.In this experiment,the genetic diversity of quinoa was analyzed using SSR molecular marker technology.The results are as follows:1.Based on the published reference quinoa genome sequence,the SSR sites in the whole genome sequence was identified by the MISA software.Then 113 SSR sites among genes was screened and primers of 113 SSR molecular markers were designed.2.The optimal melting temperature（Tm value）of these primers was screened and the PAGE conditions were optimized.Seventy-four SSR molecular markers were obtained for subsequent polymorphism analysis.3.Polymorphism analysis was performed on genomic DNA of 95 different quinoa varieties with 74 SSR molecular markers.69 molecular markers with clear bands and polymorphisms were obtained.4.Polymorphism analysis was performed on the parents of 19 quinoa hybrid combinations with the selected SSR molecular markers,and the 71 F₁plants were identified.There were 50 heterozygotes in 71 F₁plants,19 of which were maternal genotypes,and 2 F₁plants lacked parental material could not be identified.5.Seventy-nine F₂plants of a heterozygous F₁plants were selected to verify its separation.The separation ratio of F₂plants was approximately 3:1 according to one band.The results showed that the SSR marker designed in this experiment can clearly identify alleles and evaluate heterozygosity.It is consistent with the diploid genetic law of most traits of quinoa in previous studies.This project established a set of SSR molecular marker of quinoa.Through research on F₁and F₂plants,19 hybrid combinations were analyzed.This laid the foundation for selecting parents for hybridization,breeding new varieties,and collection,classification,the adaptive selection,identification and promotion of quinoa germplasm resources.