COLUMBIA, Mo. — To the casual observer, one corn plant looks pretty much like another. It hasn't always been so, and the evidence is on display at the University of Missouri Gene Zoo. The corn and soybean plot at MU Bradford Research & Extension Center near Columbia demonstrates the astonishing evolution of those two commodity crops, from their wild prehistoric state to the latest in genetically bred lines.
"This gives us the historical perspective," MU agronomist Bill Wiebold told a gathering at the MU Crop Injury Clinic. "It really shows what a great job our plant breeders and growers have done."
Wiebold began the tour standing next to a small stand of teosinte, the wild ancestor of the corn plant. "It still grows wild in southern Mexico. Corn was first domesticated about 8,000 years ago. The Native Americans took teosinte and did a pretty good job breeding corn." The plants are about 3 feet tall, producing ears only a few inches long containing only about 10 kernels apiece. "It looks a little like the head on gamma grass," he said.
Next in the evolution of corn were the open-pollinated varieties that dominated U.S. agriculture through the early 1900s. Although recognizable as corn plants, lines like Longfellow — an early open-pollinated variety — are significantly shorter and lower-yielding than modern hybrids.
"Open-pollinated varieties are very diverse in genetics, so you get short ones and tall ones," Wiebold said. "Farmers back then would save the seeds to plant the following season." The Gene Zoo also contains a stand of Gourd Dent/New England flint cross. "This was an accidental crossing that led to the hybrids we use today."
As plant breeding grew in sophistication, lines like U.S.-13 — "the first widely planted double-cross hybrid" — caught on with farmers, Wiebold said. "They found that this plant produces a lot of seed, and that helped get the farmers hooked on hybrids in the 1960s and 1970s."
Today, corn hybridization has moved to a new level. Some of the plants at the Gene Zoo are specially bred to have huge kernel embryos that yield corn oil or high-extractable, high-protein starch.
Soybean breeding developed along the same lines as corn hybridization, Wiebold said, pointing to a patch of weedy-looking plants that look nothing like modern soybeans. These are Glysine soja.
"It's wild soy, the ancestor of what we grow today," he said. "It grows in China and produces a black seed about the size of a BB. As you can see, we've come a long way."
Frequently, soybean science returns to its roots. "Scientists still go to China and collect genotypes from these areas," Wiebold said. For instance, MU soybean breeder Sam Anand found old varieties introduced from China that were resistant to the soybean cyst nematode, the No. 1 pest in soybeans. Now, almost every cultivated soybean line contains genes for SCN resistance.
Soybean lines today are bred to thrive in specific environments and to resist certain pests and pathogens, Wiebold said, pointing out the differences in the varieties of plants in the Gene Zoo. He noted an example of how nature can control pests: "Pubescence" is the term for a peach-fuzz-like covering on soybeans that discourages insects by making it more difficult for them to pierce and feed on the plants.
Other varieties on display include specialty soybeans for tofu, natto and other foods popular in Asia. "We often call these edible soybeans," Wiebold said. "But really, all soybeans are edible."
To get to Bradford Center, go about five miles east of Columbia on New Haven Road, then a mile south on Rangeline Road. Bradford superintendent Tim Reinbott said scout troops, science classes and others "can come out here and see this anytime they want to."
Forrest Rose is an Extension and ag information specialist with the University of Missouri.