The easily produced and readily identifiable strains of corn made it a favorite subject for experimental genetics. The development of hybrid corn seed was an early (beginning of the 20th cent.) and revolutionary introduction of the principles of theoretical science into practical agriculture. At first ridiculed, the scientifically developed hybrids came to represent most commercially grown corn types. They resulted in higher yields, increased sugar and lowered starch content, and uniform plants bred to specification for mechanical harvesting. Most recently, genetic engineering has produced corn with added sweetness, disease resistance, and other desired traits.