Virginia Walbot has ten reasons in the latest issue of PLOS genetics. PLOS journals are all open access so anyone can read it without a subscription.
The two reasons I think will be the most interesting to non-biologists are #1 and #10:
Corn was domesticated a short 10,000 years ago and domestication is normally a huge genetic bottleneck that results in the loss of much of the gene diversity found in the wild ancestor. (Modern tomatoes are more diverse than heirlooms because breeders are intentionally working to bring some of that diversity back over.) Yet two lines of corn, which certainly shared many common ancestors in the last 10,000 years, contain more genetic differences than humans and chimpanzees which have been evolving separately for 3.5 MILLION years. That’s 10,000 years vs 3,500,000 years!
Number ten drives home how essential corn is to the world today with statistics like American farmers growing so much corn last year than it works out to a metric ton for every man, woman, and child in this country. Or that corn and cornfeed animals feed a billion people around the globe (those aren’t rice numbers, but hopefully it drives home why corn has definitely earned it’s place as one of the big three grains that support civilization around the world).
h/t to the beekeeper (who I haven’t see around the blog in months) for pointing me at this PLOS genetics coverage of the maize genome papers coming out both there and in Science.