A new type of hybrid bream derived from a hybrid lineage of Megalobrama amblycephala (♀) × Culter alburnus (♂)

Abstract

Distant hybridization is an important technique and a useful strategy to obtain new germplasm resources. In this study, we obtained a new type of hybrid bream (BBTB) by two rounds of backcrossing from an established hybrid lineage of blunt snout bream (Megalobrama amblycephala, 2n = 48, BSB, ♀) × topmouth culter (Culter alburnus, 2n = 48, TC, ♂). The DNA content, chromosomal number, morphological traits, gonad histology, genetic composition, and muscle composition of BBTB were investigated. The determined DNA content, chromosomal number, and gonad histology showed that BBTB was a bisexual fertile diploid hybrid fish with 48 chromosomes. Analyses of the genetic composition revealed that the 5S rDNA and HoxD10a of BBTB were inherited from the two genomes of the original parents (BSB and TC). Analysis of muscle composition showed that BBTB possessed higher muscle protein levels and lower muscle carbohydrate levels than BSB. The newly obtained BBTB has the potential to establish a new diploid hybrid lineage and is highly significant for fish genetic breeding.