Comparative analysis of intermuscular bones in hybrid of female (megalobrama amblycephala × culter alburnus) × male megalobrama amblycephala and its parents

Based on the formation of the hybrid lineage of blunt-snout bream (megalobrama amblycephala, BSB) × topmouth culter (culter alburnus, TC), a new kind of hybrid fish is produced by hybridizing the female diploid F1 hybrid of BSB × TC (short for BT) with male BSB. In order to investigate intermuscular bones variety in the distant hybrid progeny, the number, morphology, and distribution of intermuscular bones in the hybrids and its parents are analyzed. The number of intermuscular bones in BSB, TC, BT and the hybrid (BT × BSB, short for BTB) ranges from 112 to 119 (x =116.1), 126 to 136 (x =130.2), 121 to 139 (x =129.6) and 116 to 125 (x =119.9), respectively. The number in BTB is significantly lower than TC and BT (P < 0.05). The average number of intermuscular bones in each sarcomere is 0.6971 (BTB), 0.7256 (TC), 0.7570 (TC) and 0.8100(BT), respectively, which indicates that the BTB has the lowest intermuscular bones in each sarcomere. In morphology, the intermuscular bone of these four kinds of fish are divided into seven shape categories and higher in the anterior intermuscular bones than in the posterior body. These studies show that the BTB not only inherits the advantage traits from BSB (with less intermuscular bones), but also gains variant traits (with lowest intermuscular bones in each sarcomere), which are beneficial to its direct edible and deep processing in industry. This study proves that it is possible to produce superior varieties with lower intermuscular bones by distant hybridization, which has some significance in fish genetic breeding.