These data support the linked publication. Full details of data collection and analysis are provided in the manuscript, with a brief explanation given here. These data relate to experiments done to uncover the genetic architecture of shoot branching in the model plant Arabidopsis thaliana. To address this, we used an artificial selection approach, combined with genome sequencing and simulations. The data in this repository include the trait measurements done on all individuals recorded during the experiment (both raw data as well as processed files, with derived and summary statistics already calculated). We also include processed genome-wide statistics estimated from the sequencing data (summarised across windows of varying widths). Finally, we also include the results from our simulations, which were used to help interpret the genomic signals obtained. More detailed information about the data files (file format and column metadata) is given in the README.txt file within this repository. These files can be used to recreate the results and figures in our manuscript. The analysis code used to generate the processed files and figures can be found in our Github repository (see related resources). The raw sequencing data was uploaded to NCBI's BioProject accession PRJNA611751 (see related resources).