Bud burst phenology of clonal Populus nigra cv. Italica in a common garden experiment

Bud phenology crucially determines the fitness of trees in their local environment and has shown to be highly heritable. Adjusted to seasons and sensitive to environmental cues, it determines the start of the growing season. However, under current climate change, genetic adaptation might be too slow to keep track with fast temperature changes. Current research suggests that epigenetic mechanisms might contribute to a fast plastic response of plants, but our knowledge about the importance of epigenetics in trees is still limited. For studying epigenetic-based variation and inheritance of phenotypic plasticity, the Lombardy poplar (Populus nigra ´Italica´ Duroi) is an ideal model. The male clone line has been propagated vegetatively for almost three centuries and has been planted all over Europe. Here, we investigated bud burst phenology in ramets of Lombardy poplars. Ramets were collected at 12 sites across a large environmental gradient in Europe and were planted in a common garden in Central Germany. Bud burst was monitored for 374 individuals in spring 2019. Since their mother trees are supposed to hold local ecotypes, we expect variation in bud burst in the common environment. Mixed-effects models will be used to investigate correlations between timing of bud burst and geographic and climatic variables of the sampling sites such as. First results will be presented during the conference.