Identification of quantitative trait loci for growth-related traits in the swimming crabPortunus trituberculatus

Abstract

The swimming crab (Portunus trituberculatus) is an economically important species in Asian aquaculture. Implementing growth-related traits of P. trituberculatus into genetic breeding programmes is an ongoing effort. We used a previously published genetic linkage map of P. trituberculatus, containing 55 simple sequence repeat (SSR) markers and 172 amplified fragment length polymorphism (AFLP) techniques to map quantitative trait loci (QTL) for growth-related traits in a single full sibling F2 family. Ten growth-related traits were measured for QTL mapping. Composite interval mapping identified 9 QTL on the female map and 16 on the male map. Individual QTL with additive effects explained 11–38% of the phenotypic variance for various traits using the female parent's map, and from 1% to 21% using the male parent's map. Two QTL explaining a large percentage of variation in body weight were detected on chromosome 17 on the female map, and on chromosome 16 on the male map, and contributed 38% and 18% of the phenotypic variance respectively. This is the first study to report the detection and positioning of major QTL affecting growth in a true crab species (Brachyura). The mapping of growth-related QTL in this study raises the possibility of improving the growth of P. trituberculatus through marker-assisted selection.