Center for Quantitative Genetics and Genomics, Aarhus University, C. F. Møllers Allé 3, 8000, Aarhus, Denmark.
VikingGenetics, Ebeltoftvej 16, 8960, Randers SØ, Denmark.
Genet Sel Evol. 2024 Nov 4;56(1):71. doi: 10.1186/s12711-024-00938-y.
The aim of this study was to compare genetic gain and rate of inbreeding for different mass selection breeding programs with the aim of increasing larval body weight (LBW) in black soldier flies. The breeding programs differed in: (1) sampling of individuals for phenotyping (either random over the whole population or a fixed number per full sib family), (2) selection of adult flies for breeding (based on an adult individual's phenotype for LBW or random from larvae preselected based on LBW), and (3) mating strategy (mating in a group with unequal male contributions or controlled between two females and one male). In addition, the numbers of phenotyped and preselected larvae were varied. The sex of an individual was unknown during preselection and females had higher LBW, resulting in more females being preselected.
Selecting adult flies based on their phenotype for LBW increased genetic gain by 0.06 genetic standard deviation units compared to randomly selecting from the preselected larvae. Fixing the number of phenotyped larvae per family increased the rate of inbreeding by 0.15 to 0.20% per generation. Controlled mating compared to group mating decreased the rate of inbreeding by 0.02 to 0.03% per generation. Phenotyping more than 4000 larvae resulted in a lack of preselected males due to the sexual dimorphism. Preselecting both too few and too many larvae could negatively impact genetic gain, depending on the breeding program.
A mass selection breeding programs in which the adult fly is selected based on their larval phenotype, breeding animals mate in a group and sampling larvae for phenotyping at random over the whole population is recommended for black soldier flies, considering the positive effect on rates of genetic gain and inbreeding. The number of phenotyped and preselected larvae should be calculated based on the expected female weight deviation to ensure sufficient male and female candidates are selected.
本研究旨在比较不同质量选择育种方案的遗传增益和近交率，以提高黑水虻幼虫体重（LBW）。这些育种方案在以下方面存在差异：（1）个体表型的抽样（要么在整个群体中随机，要么在全同胞家系中固定数量），（2）用于繁殖的成虫的选择（基于 LBW 的成虫个体表型或基于 LBW 预先选择的幼虫的随机选择），以及（3）交配策略（群体中雄性贡献不均等的交配或两个雌性和一个雄性之间的受控交配）。此外，还改变了表型和预先选择幼虫的数量。个体的性别在预先选择期间未知，并且雌性 LBW 较高，导致更多的雌性被预先选择。
与随机从预先选择的幼虫中选择相比，根据 LBW 对成虫进行表型选择可将遗传增益提高 0.06 个遗传标准差单位。每家族固定表型化幼虫的数量会使每代近交率增加 0.15%至 0.20%。与群体交配相比，受控交配可使每代近交率降低 0.02%至 0.03%。对超过 4000 个幼虫进行表型分析会由于性别二态性而导致缺乏预先选择的雄性。根据育种方案的不同，过少或过多地预先选择幼虫可能会对遗传增益产生负面影响。
考虑到遗传增益和近交率的积极影响，建议在黑水虻中采用一种基于幼虫表型选择成虫的大规模选择育种方案，动物繁殖时群体交配，随机抽样整个群体的幼虫进行表型分析。应该根据预期的雌性体重偏差来计算表型和预先选择幼虫的数量，以确保有足够的雄性和雌性候选者被选择。
