Data from: Inbreeding depression affects the growth of seedlings of an African timber species with a mixed mating reproductive system, Pericopsis elata (Harms) Meeuwen

Selfing or mating between related individuals can lead to inbreeding
depression (ID), which can influence the survival, growth and evolution of
populations of tree species. As selective logging involves a decrease in
the density of congeneric partners, it could lead to increasing biparental
inbreeding or self-fertilization, exposing the population to higher ID. We
assessed the influence of inbreeding on the growth of a commercial timber
species, Pericopsis elata (Fabaceae), which produced about 54% of
self-fertilized seedlings in a natural population of the Congo basin. We
followed the survival and growth of 540 plants raised in a plantation
along a gradient of plant density (0.07 to 15.9 plants per m2). Parentage
analysis allowed us distinguishing selfed and outcrossed seedlings. The
annual growth was higher for outcrossed than selfed plants, on average by
10.8% for diameter and 12.9% for height growth. Based on the difference in
above ground biomass between selfed and outcrossed seedlings after 41
months, we estimated the level of ID at d = 0.33, while a lifetime
estimate of ID based on the proportions of selfed plants at seedling and
adult stages led to d = 0.7. The level of ID on growth rate did not change
significantly with age but tended to vanish under high competition.
Pericopsis elata is a particularly interesting model because inbreeding
depression is partial, with about 26% of reproducing adults resulting from
selfing, contrary to most tropical tree species where selfed individuals
usually die before reaching adulthood. Hence, the risks of ID must be
considered in the management and conservation of the species.