Data from: On the widespread capacity for and functional significance of extreme inbreeding in ferns

Homosporous vascular plants utilize three different mating systems, one of which, gametophytic selfing, is an extreme form of inbreeding only possible in homosporous groups. This mating system results in complete homozygosity in all progeny and has important evolutionary and ecological implications. Ferns are the largest group of homosporous land plants, and the significance of extreme inbreeding for fern evolution has been the subject of debate for decades. We cultured gametophytes in the laboratory and quantified the relative frequencies of sporophyte production from isolated and paired gametophytes, and examined associations between breeding systems and several ecological and evolutionary traits. The majority of fern species studied show a capacity for gametophytic selfing, producing sporophytes from both isolated and paired gametophytes. While we did not follow sporophytes to maturity to investigate potential detrimental effects of homozygosity at later developmental stages, our results suggest that gametophytic selfing may have greater significance for fern evolution and diversification than has previously been realized. We present evidence from the largest study of mating behavior in ferns to date that capacity for extreme inbreeding is prevalent in this lineage, and we discuss its implications and relevance and make recommendations for future studies of fern mating systems.同型孢子维管植物（Homosporous vascular plants）拥有三种不同的交配系统，其中配子体自交（gametophytic selfing）是仅在同型孢子类群中才可能存在的极端近亲繁殖形式。该交配系统可使所有子代完全纯合，具有重要的进化与生态学意义。蕨类植物是陆生同型孢子植物中最大的类群，而极端近亲繁殖对蕨类植物进化的意义数十年来一直是学界争论的焦点。本研究在实验室条件下培养配子体，量化了单独培养与配对培养的配子体产生孢子体（sporophyte）的相对频率，并分析了交配系统与多项生态及进化性状之间的关联。本次研究涉及的多数蕨类物种具备配子体自交能力，可通过单独培养的配子体与配对培养的配子体均产生孢子体。尽管本研究未追踪孢子体至成熟阶段以探究纯合性在后续发育阶段可能产生的不利影响，但研究结果表明，配子体自交对蕨类植物进化与物种分化的重要性可能远超此前的认知。本研究基于目前为止规模最大的蕨类植物交配行为研究，提供了证据表明极端近亲繁殖能力在该演化支中普遍存在，并讨论了其相关意义与研究价值，同时为未来蕨类交配系统的相关研究提出了建议。