Food security is one of the main topics of today's agriculture
especially facing challenging environmental conditions. As most
humankind has a daily intake of cereal grains, current breeding programs
focus on these crop plants. Within the breeders' toolbox, customised
endonucleases became included after this universal application had been
demonstrated. Due to technological restrictions, the main focus was on
aboveground plant organs, while the essential belowground has been given
only limited attention. In the present review, we summarise the
knowledge on the root system architecture in cereals, the importance of
phytohormones in this physiological process, and the molecular
mechanisms involved. The review summarises how the use of the CRISPR
methodology can improve the root system architecture to enhance crop
production genetically. Finally, future research directions involving
all this knowledge and technical advances are suggested.