Half-sib (HS) mating is the most important breeding method of open-pollinated sexual forage grasses such as tall fescue. Progeny testing procedures of half-sib families can only measure general combining ability (GCA) due to the unknown pollen donor. In tall fescue, genetic studies using HS mating and application of molecular markers for paternity identification in polycross progenies are so far limited. In this study, 960 genotypes from sixteen half-sib families of tall fescue derived from polycrosses, along with their corresponding parental genotypes were evaluated for agro-morphological traits in the field during 2016 and 2017. Genetic diversity of the parental genotypes was assessed using twenty EST-SSR markers and then a minimal set of primers was used to identify the most likely male parent in the polycross progenies. Considerable genetic variation was observed among the parental genotypes based on both morphological and molecular assessments. Moderate to high estimates of narrow sense heritability (0.53–0.84) for morphological traits indicated that phenotypic selection can be successful to achieve genetic progress. The EST-SSR markers allowed to identify a unique paternal parent in 177 of the offspring which were divided into 66 full-sib families. The number of genotypes per full-sib family varied from 1 to 11. Marker data used to identify full-sib families, estimate specific combining ability (SCA), and select siblings based on the genetic value of both parents. No clear association was found between GCA of parents and the corresponding SCA for forage yield, indicating that both additive and dominant gene actions may play a role in the genetic control of this trait. The obtained results highlighted the importance of marker-based paternity identification to increase gain from selection in polycross breeding programs of tall fescue.

中文翻译：

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通过基于标记的亲子鉴定和配合力估计增强高羊茅多交育种

半同胞（HS）交配是开放授粉的有性牧草如高羊茅最重要的育种方法。由于未知的花粉供体，半同胞家族的后代测试程序只能测量一般配合力（GCA）。在高羊茅中，使用 HS 交配和应用分子标记在多交后代中进行亲子鉴定的遗传研究是有限的。在这项研究中，在 2016 年和 2017 年期间，评估了来自 16 个来自多交的高羊茅半同胞家族的 960 个基因型及其相应的亲本基因型的农业形态性状。使用 20 个评估了亲本基因型的遗传多样性EST-SSR 标记和最小的引物组用于鉴定多交后代中最可能的父本。基于形态学和分子评估，在亲本基因型之间观察到相当大的遗传变异。对形态性状的狭义遗传力 (0.53–0.84) 的中等至高估计表明表型选择可以成功实现遗传进展。EST-SSR 标记允许在分为 66 个全同胞家族的 177 个后代中识别唯一的父本。每个全同胞家族的基因型数量从 1 到 11 不等。标记数据用于识别全同胞家族、估计特定结合能力 (SCA) 并根据父母双方的遗传价值选择同胞。未发现父母的 GCA 与相应的牧草产量 SCA 之间存在明显关联，表明加性基因和显性基因作用都可能在该性状的遗传控制中发挥作用。获得的结果强调了基于标记的亲子鉴定对于增加高羊茅多交育种计划中选择收益的重要性。