Zea L., Corn/Maize
Corn or more accurately maize, Zea mays L., is the most productive cereal crop in the world, and of the major grain crops it is the only one originating in North America besides wild rice Zizania aquatica L. The history of all grain domestication is interesting, but maize is the most amazing considering how it went from a tropical multi-branched grass with each branch having both lateral ears and a terminal tassel, to a essentially single stem plant that matures in a temperate growing season, has axillary female flower spike (ears) (actually terminating secondary branches), and with a male tassel terminal on the main stem. Genetic analysis showed the primary morphological differences to be due to five gene mutations where the expression of these genes are influenced by sets of tightly linked genes on different chromosomes. These traits changed the four aspects of the cob structure and its position. One notable trait common to all domesticated grains is non-shattering fruiting structures. Other minor traits result in the corn varieties (pod corn, dent corn, flint corn, pop corn, flour corn, and sweet corn) with the most important differences between them being the starch, while grain and/or cob color is apparently independent of those traits.