Departamento de Ciências Florestais e da Madeira, Universidade Federal do Espírito do Santo, Jerônimo Monteiro, Espírito Santo, 29550-000, Brasil.
Departamento de Ciências Ambientais, Universidade Federal de São Carlos, Sorocaba, São Paulo, 18052-780, Brasil.
BMC Plant Biol. 2024 Sep 13;24(1):858. doi: 10.1186/s12870-024-05565-9.
African mahogany species (Khaya sp.) have been introduced to Brazil gaining increasing economic interest over the last years, as they produce high quality wood for industrial applications. To this date, however, the knowledge available on the genetic basis of African mahogany plantations in Brazil is limited, which has driven this study to examine the extent of genetic diversity and structure of three cultivated species (Khaya grandifoliola, Khaya senegalensis and Khaya ivorensis) and their prospects for forest breeding.
In total, 115 individuals were genotyped (48 of K. grandifoliola, 34 of K. senegalensis and 33 of K. ivorensis) for 3,330 filtered neutral loci obtained from genotyping-by-sequencing for the three species. The number of SNPs varied from 2,951 in K. ivorensis to 4,754 in K. senegalensis. Multiloci clustering, principal component analysis, Bayesian structure and network analyses showed a clear genetic separation among the three species. Structure analysis also showed internal structure within each species, highlighting genetic subgroups that could be sampled for selecting distinct genotypes for further breeding, although the genetic distances are moderate to low.
In our study, SNP markers efficiently assessed the genomic diversity of African mahogany forest plantations in Brazil. Our genetic data clearly separated the three Khaya species. Moreover, pairwise estimates of genetic distances among individuals within each species showed considerable genetic divergence among individuals. By genotyping 115 pre-selected individuals with desirable growth traits, allowed us not only to recommend superior genotypes but also to identify genetically distinct individuals for use in breeding crosses.
非洲桃花心木（Khaya sp.）近年来在巴西得到了越来越多的经济关注，因为它们为工业应用生产高质量的木材。然而，迄今为止，关于巴西非洲桃花心木种植园的遗传基础的知识有限，这促使本研究检验了三个栽培品种（Khaya grandifoliola、Khaya senegalensis 和 Khaya ivorensis）的遗传多样性和结构及其在森林育种中的前景。
总共对 115 个个体（K. grandifoliola 的 48 个，K. senegalensis 的 34 个，K. ivorensis 的 33 个）进行了基因型分析，用于对三个物种进行测序的 3,330 个过滤中性基因座。SNP 的数量从 K. ivorensis 的 2,951 个到 K. senegalensis 的 4,754 个不等。多基因座聚类、主成分分析、贝叶斯结构和网络分析表明，三个物种之间存在明显的遗传分离。结构分析还显示了每个物种内部的结构，突出了可以用于选择不同基因型进行进一步育种的遗传亚群，尽管遗传距离中等偏低。
在本研究中，SNP 标记有效地评估了巴西非洲桃花心木人工林的基因组多样性。我们的遗传数据清楚地将三个 Khaya 物种分开。此外，每个物种内个体之间的遗传距离的成对估计表明个体之间存在相当大的遗传分歧。通过对 115 个具有理想生长性状的预选个体进行基因分型，不仅允许我们推荐优良基因型，还可以识别用于杂交育种的遗传上不同的个体。
