A crop season that never failed to amaze saved the biggest surprise for last: an above-average corn harvest.

Following a spring and summer that featured either too much or too little rain at inopportune times, Indiana farmers didn't expect corn yields exceeding 150 bushels per acre. Purdue University agronomists were right there with them.

Eyebrow-raising yields of 200 bushels per acre or more were recorded at many research plots in Purdue's annual corn performance trials, said Phil DeVillez, Purdue agronomist and field trial coordinator.

"We were a little concerned at harvesttime about what our yield levels would look like," DeVillez said. "But as we harvested our plots, we were pleasantly surprised at the yields. Some of our best corn yields were 240 bushels per acre, which was excellent. The test average was 150 bushels per acre."

Even yields on poorer soils that failed to receive adequate rainfall were not disastrous, DeVillez said. "Some of the lowest yields were on our sand plots. The yields on those plots were around 100 bushels an acre," he said.

Corn performance trial results are available online at http://www.agry.purdue.edu/pcpp/corn.html. The printed version is available by contacting DeVillez at (765) 494-0406 or calling a local office of Purdue Extension.

Field trial plots were planted at 13 Purdue- and privately owned farms from Valparaiso, Ind., to Evansville, Ind. Planting was completed by May 10, and harvest was finished by mid-October. Corn hybrids were planted in four-row plots with only the middle two rows counted toward trial data. Common fertilizer and tillage practices were used and similar maturing varieties were tested together to ensure fair comparisons.

About 35 seed companies provided seed corn for the field trials, DeVillez said. Both conventional and genetically modified (GMO) hybrids were tested.

"We tested about 400 different hybrids," DeVillez said. "We probably had more GMOs this year than we had conventionals. Among the biotech hybrids, we had everything from the triple-stacked traits to the rootworm-resistant, so there was quite a wide range of hybrids in the mix."

In addition to yield, hybrids were measured for standability and grain moisture.

"You'll see a good mix when you look at the results," DeVillez said. "There are conventional hybrids that are right up at the top of the test, and there are GMO hybrids that are right up at the top of the test. I think a lot of it goes back to the maturity of the hybrid, its growth cycle as far as when it gets rain when it needs rain, and when it gets nitrogen if it is available. Given the right conditions, hybrids have a great range and ability for yield."

Weather played havoc with the growing season. Hurricane-remnant thunderstorms soaked southern Indiana cornfields early on, threatening to damage plant roots. In northern Indiana, dry conditions jeopardized plant development. Despite the weather extremes, much of the state's corn crop held up, DeVillez said.

"Timing on rainfall is a big issue. A quarter-inch here, a half-inch there can really make or break a crop," he said. "Indiana was lucky. We were on the dry side, especially in the north, but we got the timely rains when we needed them. We also had a lot of sunny days this year. Sunlight also affects yield. When you get more sunny days there's more photosynthesis. As long as it's not too hot and the plant is not shutting down, that translates to bigger yields, as well."

Indiana farmers are projected to harvest 868.2 million bushels of corn in 2005 at an average of 151 bushels per acre, according to a Nov. 10 report by the U.S. Department of Agriculture. The yield average is lower than the record 168 bushels an acre Hoosier corn growers posted in 2004.