Genetic relatedness can alter the strength of plant-soil feedbacks

Premise: Intraspecific variation may play a key role in understanding the relationships between plants and their interactions with soil microbial communities. The soil microbes of individual plants can generate intraspecific variation in responsiveness of offspring, yet remains much less studied. To address this need, we explored how seedling relatedness to established Solidago altissima clones altered the plant-soil feedbacks that they experienced.Methods: Seedlings of known parentage were generated from a series of 24 clones grown in a common garden. Seedlings from these crosses were inoculated with soils from maternal, paternal, or unrelated clones and their performance compared to sterilized control inocula.Results: We found that soil inocula generated from S. altissima clones had an overall negative effect on seedling biomass. Furthermore, seedlings inoculated with maternal or paternal soils tended to experience larger negative effects than seedlings inoculated with unrelated soils. However, there was much variation among individual crosses, with not all responding to relatedness.Conclusions: Our data argue that genetic relatedness to the plant generating the soil microbial community may cause differential impacts on establishing seedlings, encouraging the regeneration of non-kin adjacent to established clones. Such intraspecific variation represents a potentially important source of heterogeneity in plant-soil feedbacks with implications for maintaining population genetic diversity.