Genetic Evolution And Related Species Research Of Mythimna Separata In The Overwintering Range

The oriental armyworm, M. separata (Walker) is a long distance migratory pest harming crop in China. Every year heavy loss is caused to food production in China through seasonal migratory. Armyworm in overwintering region as the starting migrated source will directly affects the following occurrence. So the research of overwinter armyworm has a great significance to the work of armyworms monitoring and forecast. In this paper by means of molecular biology to research the population genetic evolution of armyworm and armyworm relatives captured in the overwintering region, in order to obtain the rapid identification of armyworm relatives and population structure characteristics of armyworm in China and now be summarized as follows.In our project we developed a total of 2132362 SLAF tags and 2119990 SNPs. Through the second round of the quality of the filter we get 26,380 high reliability SNP loci. Among them,199 SNP loci were annotated. Based on phylogenetic tree analysis and PCA analysis of 80 samples from the four overwintering regions,80 samples could be divided into two groups. The 20 individual from Guangdong gathered in a trend and have a clear distinction with the 60 samples from Guangxi, Yunnan and Fujian. While the 60 individual from Guangxi, Yunnan and Fujian are not significantly divided. Through the analysis of Fst group selection we try to find the outlier SNP marker that can differentiate Guangdong from the other three regions. At last we got 101,108 and 100 that can differentiate Guangdong from Fujian, Guangxi and Guangdong respectively. In order to discovery highly divergent loci that can differentiate the population come from Guangdong from that from the other three regions, genotype frequency difference less than 0.8 were removed. At last 95 SNP show large allele frequency differences which can be used as the regional characteristics SNP marker. The 95 SNP provide the available molecular markers for further study of armyworm migration trajectories in China.This paper we have identified four kind of armyworm M. separata (Walker) relatives through morphological identification and DNA barcode technology and done further verification about the molecular genetic features of 4 kinds of armyworm relatives. The result illustrated that Four M. separata related species were found through morphological identification identified as L. loreyi, L. roseilinea. L. pallidior. A. pseudaletiana, respectively. The COI gene sequences of DNA barcode were obtained for the first time in L. roseilinea、L. Pallidior and A. Pseudaletiana by the PCR amplification and sequencing of DNA barcode COI gene through universal primer. The results of sequence analysis showed that the lengths of COI gene fragment of the four kinds of noctuidae are all 658bp. The L. loreyi, L. roseilinea, L. pallidior, A. pseudaletiana share 93.31%,92.86%,91.95% and 90.88% identity with A/. separata respectively and 100%,100%,100%,99.09% and 99.09% with amino acid sequences coded by COI gene. The pairwise distance between the four noctuidae above with M. separata is 0.067,0.071, 0.081 and 0.091 respectively. Synthesize the genetic distance analysis and homologous identity analysis, the 4 M. separata related species with the most closed genetic relationship with M. separata were, in order, L. loreyi, L. roseilinea, L. pallidior and A. pseudaletiana.