Heritability of early seedling growth in Taxus baccata, a declining conifer.

In the face of ongoing climate change, understanding adaptive potential is crucial for conserving the functional biodiversity of forests. In trees, early growth influences competitive ability, rendering seedling attributes suitable candidates for adaptive traits. However, determining whether any trait contributes to the evolutionary potential requires proving its heritability. Such knowledge is important, among others, for understanding the current status of declining tree species, such as the common yew. In this study, we aimed to estimate the heritability of early seedling growth in yew. To achieve this, we collected seeds from two remnant populations and subjected them to germination. We then established a greenhouse experiment to grow seedlings. Using paternity analyses, we determined the relatedness between seedlings. Subsequently, the additive genetic variance in the height of 4-month-old seedlings was estimated using a Bayesian model, taking into account maternal and population effects. Our results indicated that seedling height heritability was 0.17 to 0.46, depending on the level of conservatism applied, while we found no apparent maternal effect, despite the significant variation in germination between mother trees. The findings suggest that early growth may be subject to evolutionary change in yew, provided that the trait is an important fitness component.