Morphological Characteristics, Genetic Diversity, and Microsatellite Analysis of the Progenies (F1, F2, and Backcross Descendant) of Siniperca chuatsi and Siniperca scherzeri

Abstract

Hybridization is a common technique in the breeding of new varieties. In this study, we obtained F₁ and F₂ hybrids through interspecific hybridization between Siniperca chuatsi and Siniperca scherzeri and backcross offspring by backcrossing between F₁ and Siniperca chuatsi. We analyzed the morphological traits and genetic diversity of the parents and their progeny. The results showed that although most morphological traits of the progeny were not significantly different from those of their parents, the F₁ hybrids exhibited the most pronounced morphological variations. The F₂ and backcross hybrids appeared morphological differentiation within their populations. The CPL/CPW ratio emerged as a reliable marker for identifying hybrids morphologically. The expected heterozygosity for F₁ (0.6264), F₂ (0.6677), and backcross offspring (0.5260) were intermediate between Siniperca chuatsi (0.7388) and Siniperca scherzeri (0.3910), indicating a relatively high level of genetic diversity in the offspring. Additionally, the private allele frequency of F₁ and F₂ was higher than backcross offspring. One SSR marker (G₅₂₂₀) was identified as a specific molecular marker to distinguish the hybrid F₁ population from the parents, hybrid F₂, and backcross F₁ populations by analyzing specific alleles. The result of Ne, He, I, and PIC confirmed that F₂ maintained the genetic diversity of F₁. We speculated that both F₁ and F₂ have higher breeding potential. This study provides essential baseline data for genetic breeding of mandarin fish that will be instrumental in the future.