Plants are able to anticipate to changes of the environmental conditions triggering self-protective developmental programs. Dormancy is a complex developmental program that allows woody plants to survive the low temperatures of winter. Dormancy, therefore, determines the geographical distribution and the developmental period of the tree, which will in turn condition both the productivity and quality of its wood. In addition to the growth-dormancy cycle of the apical and vascular cambium meristems, lateral buds developmental program is seasonally controlled in temperate woody plants. The lateral buds of most temperate woody species do not grow out during the season in which they form. These proleptic buds overwinter and grow out during the following spring. However, in Poplar and a few other temperate species, as well as many tropical species, some lateral buds grow out sylleptically, that is, they grow out during the same season in which they form without an intervening rest period. Sylleptic branching in Poplar may increase significantly branch number, leaf area and the general growth of the tree, particularly in its early years. How the temperate woody plants perceive the environmental signals such as light and temperature to establish these seasonal controlled developmental programs is still poorly understood.My research goal is to investigate the crosstalk between the internal timekeeper and mechanisms related to the control of developmental programs regulated by winter dormancy in woody plants. In this proposal I will explore two complementary angles of this research line: 1) Deciphering the molecular mechanism involved in winter disruption of circadian clock in Poplar. 2) The spatio-temporal investigation of circadian regulated CsRAV1 gene network and its transcriptional mechanism to clarify the regulatory principles of dormancy eluding.The results of this project may contribute to develop trees with increased biomass yield.