Drought is a major stress that affects growth, physiology and therefore yield of a crops as sunflower. To become more tolerant, plants develop complex morpho-physiological responses. Various genes interacting between them and with the environment are involved in the genetic control of those responses. They form together a gene regulatory network (GRN) that integrates the perception of the environment, the transduction of this signal and the effector genes withholding the different responses. Here, we focused on this drought GRN, its different gene groups and their interactions in the cultivated sunflower. First, we highlighted three genes reflecting the environmental signal. From their expression we built a plant water status biomarker. Then, through an association study we built the GRN connecting drought responsive genes and we deciphered their genetic control. Finally, thanks to a systems biology approach we inferred the GRN linking regulatory and drought responsive genes. Studying this network, we examined how it could drive phenotypic changes and how it was related in Helianthus evolution and sunflower breeding.