Abstract:Portunus trituberculatus is one of the most important fishery resources in China because of its high commercial value. In recent years, it has suffered from overfishing and various diseases, and the total resource of wild populations has decreased year by year. Considering for this situation, it is necessary to study the genetic diversity and genetic linkage map of P. trituberculatus. In this study, maternal broodstock and paternal broodstock were sampled from Laizhou Bay and Zhoushan Island wild population, respectively. Through directional mating (1♂×3♀), they generated F1 family. 63 individuals of F2 family came from sisterhood intercross between F1 family and these broodstock were used as experiment materials. The AFLP analyses showed that a total of 1 742 loci were produced,of which 417 loci were polymorphic, accounting for 23.9%. In these polymorphic loci, there were 226 (accounting for 54.2% of total segregating loci) loci segregating as 1∶1 Mendelian model while 31 (7.4%) loci segregating as distorted model.128 loci (30.7%) segregated as 3∶1 model and the numbers of 32 (7.7%) loci were distortion bands. Additionally, several AFLP bands which segregated neither as 1∶1 nor as 3∶1 were named with odd segregating loci. They were treated as non-segregating loci in order to reduce the influence of statistical error. Genetic diversity index of the F2 was 0.130, and Shannon genetic diversity index was 0.193. Analysis of distances showed that Nei’s genetic distance of family with male parent and female parent were between 0.064~0.111, 0.065~0.107 respectively. In the mean time, No63 individual was most distant from its male parent and No48 individual was most distant from its female parent. The main purpose of the study was to provide the technical support for genetic diversity analysis of wild populations or families and construction of high density genetic linkage map of P. trituberculatus.
