Circadian rhythms are a fundamental feature of living organisms and are maintained by a molecular oscillator called the circadian clock. In plants, this mechanism has been shown to control biotic and abiotic stress responses, flowering time, photosynthesis, growth or fitness, among many other traits of agricultural interest. The circadian clock in plants is only well characterized in Arabidopsis, but it is clear now that this mechanism as well as its inputs and outputs are not conserved in other plant species. For example, several of the core-clock proteins from Arabidopsis are missing in tomato, while some others are duplicated. This raises the question of whether the model of the circadian clock in Arabidopsis is sufficient to understand this important mechanism in plants, the primary source of food and oxygen for out planet. We have recently shown that tomato domestication was accompanied by a significant deceleration of circadian rhythms (Müller et al., 2016). We localized the two responsible mutations, found strong signals of selection for the underlying genes, and most importantly, showed that changes in circadian rhythms have an effect in plants grown under production environments. My ERC proposal in 2016 was dedicated to generate the tools needed to build the first model of the circadian clock in a crop, to compare it with what is known from Arabidopsis and to investigate its potential to enhance plant performance for agriculture. Tomato is one of the few diploid, fast growing, self-crossing crops and there is a vast amount of genetic, genomic and molecular resources for this species. Taking advantage of the variation already present for circadian rhythms in tomato and using the latest gene editing, genomics and molecular biology technologies available for this system will allow us to consolidate the field of circadian biology in crops. This year, my ERC grant has changed significantly in the light of our new results and it has into account the suggestions from the reviewers in 2016. In this Templin-ERC proposal I request funds for technical support to set up the basic genetic material and methods for my new ERC grant, and obtain the preliminary results that will ensure the feasibility of the project.