Livestock people know this adage well- once in a while, the bull 'jumps the fence.' To old cattlemen, especially, that means that if a female was in heat, a bull would do his best to try to find her, even if she was in a different pasture, and he was supposed to stay put. In some ways, it's not that different in cornfields. Pollen has a habit of sometimes 'jumping the fence' and traveling into neighboring rows.

How far it can travel is still a point of discussion. That it can travel and pollinate corn in a nearby field is not-its fact. Dave Nanda, consultant for the Farm Progress Corn Illustrated plots at Edinburgh, Ind., proved that visually again this summer by growing white sweet corn near field corn. The white corn was separated by a five-foot alley, simulating a fence row situation.

Ears nearest the field corn contained the most yellow kernels. One ear Nanda discovered was nearly half yellow, although not in a pattern- more in an irregular patchwork of white and yellow kernels. Other ears, even close to the field corn, didn't contain as much yellow. In general, as you moved several feet away, simulating several border rows in a field situation, there were fewer and fewer yellow kernels.

So will those yellow kernels taste like sweet corn? "No, but in most cases, as you move farther out, there isn't enough of them to make you not want to eat the corn," Nanda quips. Nanda, president of Bird Hybrids, Tiffin, Ohio, is a big fan of sweet corn, especially if the kernels are plump.

In a field situation, pollen from other fields or other hybrids within the same field will also drift somewhat, as illustrated in the white sweetcorn example. Whether it's a concern or not depends upon what you're growing, and how strict the quality standards must be, Nanda notes. For some traits, just making a pass along the edge of the field and not including that first six to eight rows in the grain you're selling that is supposed to contain or not contain a trait may be enough. In other cases, it may mean establishing exact differences from one type of corn to another.

For example, when you visit the Farm Progress Show in two weeks, you will want to visit Mosnanto's exhibit. Located on the southeast corner of Progress City at the Decatur, Ill., site, the exhibit contains corn and soybeans growing that aren't yet approved to be grown in the U.S.. Not only must the crop be destroyed, but it was necessary to make sure corn wasn't planted within a specific distance of the exhibit. So even beyond the south parking lot at the show, east of Progress City, where crops begin, there will be soybeans and even some alfalfa for the first part of the field. That's so even though soybeans won't be combined for demonstration purposes at the show. Show organizers note that they needed separation distance from the Monsanto plots to comply with federal standards governing planting and growing of experimental crops containing genetically-modified traits.

How far away corn of a different kind, a different color, if you will, must be planted to avoid contamination may depend upon various factors. But it remains a fact of nature that pollen will drift. This simple exercise in the Corn Illustrated plots simply reaffirms that the drift is there. If it's yellow corn pollinating another yellow hybrid, it's not obvious. Yellow kernels scattered in patches on a white ear are hard to miss.