Sun Wenting, Yu Dade, Dong Mingliang, Zhao Jian, Wang Xiaoping, Zhang Hongjing, Zhang Jinfeng
National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Biotechnology Laboratory of State Forestry Administration, College of Biological Science and Biotechnology, Beijing Forestry University, Beijing, China.
Beijing Municipal Bureau of Landscape and Forestry, Beijing, China.
PLoS One. 2017 Apr 27;12(4):e0176483. doi: 10.1371/journal.pone.0176483. eCollection 2017.
Controlled pollination (CP) is an important tool for breeding programs to improve seed quality, as it rapidly generates desirable genotypes and maximizes genetic gains. However, few studies have evaluated the success rate of CP, especially in Larix gmelinii var. principis-rupprechtii Mayr. seed orchards. In this study, we estimated the rate of correct parentage in 257 CP progeny in an L. gmelinii var. principis-rupprechtii seed orchard from ten candidate parents using 13 microsatellites. The parentage exclusion probabilities of all combined loci in the single parent and parent pair tests were > 0.99, which was sufficient to distinguish the relatedness of the sampled individuals. Comparing the maximum likelihood-based parentage analysis results with breeding records revealed that the percentages of correctly identified maternal and paternal parents were 22.6% and 35.0% at 95% CL, respectively, suggestive of parent mislabeling and pollen contamination in the CP population. We conducted a pedigree reconstruction by identifying the expected parents and assigned maternity, paternity, and parent pairs to 176 (68.5%), 199 (77.4%), and 132 (51.4%) progeny, respectively. This study provides a reference for future selection of elite genotypes for commercial production. To increase the efficiency of CP, molecular markers should be used to correctly identify individuals in seed orchards before conducting CP.
控制授粉（CP）是育种计划中提高种子质量的重要工具，因为它能快速产生理想的基因型并最大化遗传增益。然而，很少有研究评估控制授粉的成功率，尤其是在华北落叶松种子园中。在本研究中，我们使用13个微卫星标记，从10个候选亲本估计了华北落叶松种子园中257个控制授粉子代的正确亲本率。单亲本和双亲本测试中所有组合位点的亲本排除概率均>0.99，足以区分采样个体的亲缘关系。将基于最大似然法的亲本分析结果与育种记录进行比较，发现在95%置信水平下，正确识别的母本和父本的百分比分别为22.6%和35.0%，这表明控制授粉群体中存在亲本标签错误和花粉污染。我们通过识别预期亲本进行了系谱重建，分别将母本、父本和双亲本分配给了176个（68.5%）、199个（77.4%）和132个（51.4%）子代。本研究为未来商业生产中优良基因型的选择提供了参考。为了提高控制授粉的效率，在进行控制授粉之前，应使用分子标记正确识别种子园中的个体。
