Identification And Evaluation Of Germplasm Resources Of Cong Jiang Rice Field Carp

Common carp(Cyprinus carpio Linnaeus)has rich endemic populations and domesticated strains in my country.Among them,Qingtian field fish,Congjiang field fish,Guangdong grass fish,Guilin grass carp,Guangxi Jinbian carp and other local rice field carps have attracted much attention.It plays an important role in the traditional rice-fish symbiosis system.The ancestors of Dong nationality in Congjiang and surrounding areas have cultivated carp in rice fields for more than a thousand years.Many villages still continue this traditional farming culture and self-breeding and self-retaining breeding system.The rice-fish-duck compound system in Congjiangdong Township has successively been awarded the “Global Important Agricultural Cultural Heritage” and the title of “National Geographical Indication of Agricultural Products” by the United Nations,which greatly promoted the cultivation and utilization of rice field carp in Congjiang County,but its genetic background was not clear,The system relationship was still uncertain,which seriously hinders its germplasm protection and breeding utilization.In order to assess the current status of rice field carp germplasm resources in Congjiang County,and reveal the morphological characteristics,genetic structure of rice field carp and its molecular system evolution relationship with domestic and foreign carp,this study was based on morphology,mitochondrial DNA Cytb gene and COI gene,and micro The satellite marker technology used Congjiang paddy field carp as the main object,and the neighboring 6 counties of paddy field carp as the control,to carry out the identification and evaluation of its germplasm resources.The main results were as follows:1.Collected 203 rice field carp from 12 townships in Congjiang,measured 14 countable and 11 measurable traits,and carried out its morphological research by sampling single-factor analysis of variance,principal component analysis and cluster analysis.The results showed that there were two carps with reunion and slender appearance in the rice fields of Congjiang.They have extremely significant differences in body height,body width and head length(P<0.01),which can be used to identify morphological differences.mark.Compared with the morphology of the main domestic carp species,the reunion rice field carp was similar to the mirror carp(Cyprinus carpio var.specularis),Xingguo red carp(Cyprinus carpio var.Xingguonensis)and Oujiang color carp(Cyprinus carpio var.color).The type of rice field carp was similar to Jian carp(Cyprinus carpio var.Jian),Heilongjiang wild carp(Cyprinus carpio haematopterus)and Yellow river carp(Cyprinus carpio).Principal component analysis showed that the main differences between Congjiang rice field carp and other carp species are the number of fins,body width and body height.The clustering results showed that the morphological relationship between the slender rice field carp and Jian carp was closer,while the more reunion rice field carp showed a greater difference.Analysis believes that the shallow water environment of rice fields may cause field fish to be different from other carp populations or strains in morphology.2.Using mitochondrial DNA Cytb gene to study the genetic composition and phylogenetic relationship of rice field carp populations in Congjiang and surrounding6 counties.The Cytb gene sequence of the 447 tails of rice field carp is 1141 bp in length,and 29 haplotypes are defined,of which 18 were unique and 11 were shared.There were 19 haplotypes in Congjiang rice field carp,and 8 were unique haplotypes.Yes,the remaining 11 were shared with the surrounding 5 groups.The results of the phylogenetic tree and blast sequence alignment showed that the 6 rice field carp populations including Congjiang were clearly divided into two pedigrees in Europe and Asia.It was composed of European carp(C.carpio carpio)and Far East carp(C.carpio haematopterus).It was composed of 3 subspecies of C.carpio rubrofuscus and South China carp(C.carpio rubrofuscus),and contains a mixed population of multiple sources of maternal lineage.The genetic distance and genetic differentiation index showed that the genetic divergence between the two carp groups in Europe and Asia was much greater than the two subspecies populations in Asia,and there was significant genetic differentiation between the three subspecies.Tracking of the maternal lineage components found that the maternal lineage components of carp artificial lines at home and abroad showed a diversified development trend in rice field carp in Congjiang and surrounding areas,but South China carp was still its main lineage component.The diversity index of the European carp population presents the characteristics of low Hd(0.324)and low Pi(0.0004),and the genetic diversity was poor,which was in line with the characteristics of the bottleneck effect or founder effect of the European domesticated carp in the early stage.The two Asian subspecies populations are high Hd.(0.828,0.854)and low Pi(0.0021,0.0028),showing quite high haplotype diversity and variability.The results of the study suggested that the rice field carp in Congjiang and its surrounding areas was a mixed group composed of3 subspecies and multiple maternal lineages,which was affected by the cross-dialysis of domestic and foreign carp breeds.3.Based on the mitochondrial DNA Cytb gene and COI gene,the genetic diversity of six paddy field populations of South China carp.Cytb gene results showed that the population has 17 haplotypes,of which 9 are unique and 8 are shared.There were 11 haplotypes in the Congjiang population,3 of which were unique,and the remaining 8 were related to surrounding populations.Sharing;Except for Jinping,which has low Hd(0.193)and low Pi(0.0004),the other 5 populations were high Hd and low Pi.Among them,the Congjiang population has the largest number of mutation sites and haplotypes and the highest haplotype Diversity,Liping has the highest nucleotide diversity;population genetic variation mainly comes from within the population(81.14%);Jinping and Sanjiang were genetically differentiated from other populations.The COI gene results showed that there were 13 haplotypes in the population,of which 8 were unique and 5 were shared.Hap13 was the dominant haplotype of each population.There were 8 haplotypes in the Congjiang population,and 3 were the same.Unique,the remaining 5 were shared with surrounding populations;except for the Sanjiang population,which has high haplotype diversity(h=0.7625)and low nucleotide diversity(Pi=0.0026),Congjiang and other 5populations have low Hd Low Pi;population genetic variation also mainly comes from within the population(80.50%);the genetic differentiation between Sanjiang and other populations was larger,and the other populations were smaller.Comprehensive analysis revealed that the exchange of seedlings of carp in rice fields from Congjiang and the surrounding neighboring areas has promoted genetic exchanges between populations.At the same time,due to geographical barriers,it also contains unique genetic resources.The high haplotype diversity indicates its domestication process for thousands of years,Accumulated rich genotypic diversity,and the lack of nucleotide diversity was related to insufficient accumulation of nucleotide mutations.4.Based on the microsatellite tagging technology,203 rice field carp from 10 sites in 12 townships in Congjiang was analyzed.The 13 pairs of microsatellite primers selected in this study have good reproducibility and were all highly polymorphic sites.A total of 84 alleles were detected.The number of alleles detected for each microsatellite locus was 5-9,with an average It is 6.4615.The PIC values of HLJ338,HLJ855,HLJ400,HLJ519 and HLJE8 related to growth traits were all greater than 0.5 in all populations,indicating that their genetic polymorphisms were high and they contain rich selection potential.Among the groups,the diversity parameters of the Cuili group were the lowest,while the Na and Ho of the plain group were the highest,and the Ne,He,I and PIC of the Luoxiang group were the highest.The PIC of the polymorphic information content of the 10 populations was between0.5417 and 0.6953(PIC>0.5),indicating that their genetic polymorphism was at a high level and has a genetic basis for breeding.The inbreeding coefficient(Fis)value of 10 loci was negative,and the remaining 3 were positive,indicating that the degree of inbreeding of Congjiang rice field carp was relatively light,indicating that the breeding method of Congjiang rice field carp multi-line carp population reduces inbreeding Probability has a special role in keeping the paternal line at a high level of genetic variation.In summary,this article evaluates the current status of rice field carp germplasm resources in Congjiang County from the morphological characteristics and molecular level,reveals the phylogenetic relationship,maternal lineage source and composition,the status of genetic diversity of rice field carp in Congjiang County,Protection,development and utilization provide a reference basis.