Study On The Morphology And Diversity Of Macrobrachium Rosenbergii Cultivated Populations

In this paper,we studied four populations Macrobrachium rosenbergii cultivated populations based on the perspective of morphology and molecular genetics by using multivariate statistical analysis,path analysis and mitochondrial ND1 gene sequencing for the purpose on clarifying their genetic backgrounds,establishing the genetic resources center,acquiring the molecular genetic marker,structuring the genetic map and provide fundamental information of cultivated a new variety with many outstanding characters.The study preliminary descriptive statistic of 16 traits data,and then futher converted into proportional parameter for multivariate statistical analysis to compare the morphological differences between the four populations of Macrobrachium rosenbergii.Descriptive statistics revealed that each trait had potential for selection.one-way ANOVA found that only B:RL/BL?D:TL/BL?H:TW/BL had no significant difference?P>0.05?among the four cultivated populations.Cluster analysis results show that the morphological variation of GX1,HN,GD,GX2 increased in turn.Extracting 6 principal components as carapace,body length and caudal peduncle,the cumulative contribution rate was 80.207%.The principal component analysis scatter plot expressed that there is a certain degree of genetic differentiation within the group.The discriminant analysis of misjudgment rate is high.The multivariate statistical method reflects the lower degree of morphological difference among the four populations of Marcobrachium rosenbergii.The path analysis was conducted to investigate the effects of 16 morphological traits on body weight.Finally,the regression equations of GD,GX1,and HN for future breeding were established and the key trait determining weight was screened as abdominal width.The ND1 gene of 213 individuals from four cultured populations of Macrobrachium rosenbergii were sequenced and analyzed for genetic diversity.The sequence length was 539 bp,with 339 polymorphic sites,and could be classified as156 haplotypes.The haplotype diversity of each population was 0.9980?GX2?to1.0000?GD?;the nucleotide diversity???was 0.03952?GD?to 0.2045?GX1?,and the higher diversity indicated that the ND1 gene could act as a rapid effectively monitor molecular markers of population genetic variation.Only GX1 and HN,GX2 and HN have a moderate degree of genetic differentiation,and the remaining is weak,the same as the genetic differentiation.The intra-population variation accounted for69.64%of the total variation,30.46%among groups,and the genetic differentiation index was 0.0668.The results of UPGMA clustering analysis showed the genetic relationship among groups.The genetic relationship between GD and GX2 was the closest,followed by GX1 and HN,GX1 and GX2 were the farthest.In the results of the morphological and genetic structure of the four cultured populations of Macrobrachium rosenbergii,the degree of genetic relationship and the degree of difference were basically identical.Through direct sequencing,five polymorphic loci associated with the traits of Macrobrachium rosenbergii were found on the coding region of mitochondrial ND1gene,which were T304C?A321-?C389T?T403C?A681G.Among the five polymorphic loci,A321-belonged to deletion mutation;T403C arginine missense mutation was glycine;T304C,C389T and A681G belonged to synonymous mutation.In these five loci,all cultivated populations deviated from the Hardy-Weinberg equilibrium state.At the T304C locus,the differences of mean in the traits of OL,RL,CL,BL,TL,CW,TW,CH,and AH were significantly different among the genotypes of the GX2 cultivated population?P<0.05?.At the A321-site,the differences of mean in the traits of TW,P₂L,P₂PL,and TH of the GD cultivated population were significant?P<0.05?,and BW,CL,ED,CW,AW were extremely significant?P<0.01?.There were significant differences of mean values in the traits of OL,BL,CL,TW,CH,TH among different genotypes of the GX2 cultivated population?P<0.05?.At the C389T locus,the GD and AH traits of different genotypes of the GD cultivated population were significantly different?P<0.05?,and the shear force was extremely significant?P<0.01?.The difference of mean value in the traits of P₂PL of different genotype traits in the GX1 cultivated population was extremely?P<0.01?.The mean values in the characters of BW,AH,TH,and shear force of different genotypes of HN cultivated population were significantly different?P<0.05?.At the T403C locus,the mean values in the characters of CL,BL,CW,AW,TW,CH,AH,TH,and drip loss of different genotypic in the GD cultivated population were significantly different?P<0.05?.Different genotypes of the GX1 cultivated population in the traits of BW,P₂L,P₂FL,and P₂PL were significantly different?P<0.05?,with P₂PW and shear force were significantly?P<0.01?.At the G681A locus,the traits of OD,TH,pH,and shear force in the different genotypes of the GD cultivated population were significantly different?P<0.05?.The mean values of pH in different genotypes of the GX1 cultivated population were significantly different?P<0.05?.The mean values in the characters of OL,TL,P₂PL and TH in different genotypic traits of the GX2 cultivated population were significantly different?P<0.05?,with the traits of CL,OL,shear force,BL,CW,AW,TW,and AH were extremely significant?P<0.01?.Therefore,ND1 gene could be used as the molecular markers of growth and meat quality as well as applied to the genetic breeding of Marcobrachium rosenbergii applications.