Quantitative trait loci (QTL) associated with growth rate trait in common carp (Cyprinus carpio)

Growth rate is one of the important economic traits in aquaculture species that is influenced by quantitative trait loci (QTLs). Recently published complete genetic map of common carp (Cyprinus carpio) with 307 markers (including 109 SSR, 31 EST-SSR and 167 SNP markers) was used to determine the number and position of QTLs effecting body weight (BW) and growth rate. Ten-, 11- and 12-month-old individuals of common carp were measured, and seven QTLs were detected in three linkage groups (LG1, LG6 and LG20); three were significant QTLs (qBW2-6, qBW3-6 and qBW3-20, P < 0.001), and four were suggestive QTLs (qBW1-1, qBW1-6, qBW2-20 and qBW3-1, P < 0.01). The three significant QTLs related to BW2 and BW3 were in LG6 and LG20 and covered 18 and 41 cM, respectively. The explained variances of qBW2-6, qBW3-6 and qBW3-20 were 34.4, 32.1 and 33.4 %, respectively. The four suggestive QTLs affecting BW1, BW2 and BW3 were in LG1, LG6 and LG20 and had variances that ranged from 17.9 to 26.7 %. The similarity of the QTL intervals for BW1, BW2 and BW3 in LG6 suggested that these genes may affect growth continuously during the early stage of growth and may be important for growth. The identification of QTLs for growth rate and BW in C. carpio will lead to a better understanding of the factors that influence these traits at a genetic level and will promote the growth to higher production through marker-assisted breeding.