目的:野生物种是通过杂交将有价值的性状引入作物的战略来源。对于花生,Arachis部分中目前描述的33种野生物种特别重要,因为它们与驯化物种的性相容性,拟南芥。尽管许多野生种质被精心保存在种子库中,它们的形态相似性对常规分类提出了挑战。
方法:使用高密度阵列,我们对272个种质进行了基因分型,涵盖了Arachis部分中的所有二倍体物种。通过系统发育分析揭示了种质与物种之间的详细关系,并利用种质收集者和策展人的专业知识进行了解释。
结果:确定了两个主要群体:一个具有A基因组物种,另一个具有B基因组,D,F,G,和K基因组。物种分组通常显示出清晰的边界。组内的结构是信息丰富的,例如,揭示了原始驯化A.senosperma的历史。然而,一些分组建议多个兄弟姐妹物种。其他人是多系的,表明需要进行分类学修订。年度物种比多年生物种更好地定义,揭示了将经典和系统发育物种概念应用于该属的局限性。我们建议为几个种质分配新物种。
结论:由种质收藏家和策展人策划,这种对物种关系的分析为未来的物种描述奠定了基础,未知种质的分类,和种质资源用于花生改良。它支持当前种质的保存和管理,这两个关键任务都考虑到栖息地丧失对属的威胁以及当前对新收藏和种质转移的限制。
OBJECTIVE: Wild species are strategic sources of valuable traits to be introduced into crops through hybridization. For peanut, the 33 currently described wild species in the section Arachis are particularly important because of their sexual compatibility with the domesticated species, Arachis hypogaea. Although numerous wild accessions are carefully preserved in seed banks, their morphological similarities pose challenges to routine classification.
METHODS: Using a high-density array, we genotyped 272 accessions encompassing all diploid species in section Arachis. Detailed relationships between accessions and species were revealed through phylogenetic analyses and interpreted using the expertise of germplasm collectors and curators.
RESULTS: Two main groups were identified: one with A genome species and the other with B, D, F, G, and K genomes. Species groupings generally showed clear boundaries. Structure within groups was informative, for instance, revealing the history of the proto-domesticate A. stenosperma. However, some groupings suggested multiple sibling species. Others were polyphyletic, indicating the need for taxonomic revision. Annual species were better defined than perennial ones, revealing limitations in applying classical and phylogenetic species concepts to the genus. We suggest new species assignments for several accessions.
CONCLUSIONS: Curated by germplasm collectors and curators, this analysis of species relationships lays the foundation for future species descriptions, classification of unknown accessions, and germplasm use for peanut improvement. It supports the conservation and curation of current germplasm, both critical tasks considering the threats to the genus posed by habitat loss and the current restrictions on new collections and germplasm transfer.