For centuries, the vast physical diversity of maize, the most popular cereal grain crop globally, has fascinated biologists and plant breeders alike. Early breeders selected the maize variants with good, preferrable traits and propagated them for a long time to develop "true breeding" or inbred lines that show the same favorable features, for instance, the desired kernel color or size, for generations. Because of scientific advances, it is now well known that these trait variations are linked with variations in the genes of maize and that any changes in the "genotype" or gene variation can lead to a new "phenotype" or maize plant variant with a different physical trait.