Roger and Nick Wenning, Greensburg, believe in putting out test plots to see what works on their own farm. They test various hybrids vs. one another, but they also test practices, such as different planting rates for seed and fungicide treatment vs. no treatment in corn later in the season.
The results of their on-farm trial for corn this past season raise some interesting points. The farm-size trial contained 28 different hybrid entries (26 with the check hybrid used three times). It was not replicated. There was a strip of corn of a hybrid at one population next to the same hybrid at a different population across the field.
The populations will sound high, but you need to know they plant in twin-rows. They have used a Great Plains planter to plant in twin-rows for several seasons and believe it's paying off in terms of higher corn yields.
This past year they compared each hybrid at 39,000 and 45,000 seeds planted per acre. When the results came back, three-fourths of the hybrids performed better at the higher population. However, one-fourth actually yielded more at 39,000. And when you put economics into the equation, primarily just counting for extra seed cost to go from 39,000 to 45,000, then less than 6 of 10 of the hybrids planted at 45,000 vs. 39,000 actually at least paid for the cost of the seed.
With a few hybrids the increased yield for higher population was dramatic. Since the plot wasn't replicated, it's not possible to say if the results would repeat themselves, but they do raise questions.
A handful of different companies had hybrids in the plot. All but one company had at least one hybrid that yielded more at 39,000 than 45,000 seeds per acre, even if their other hybrids did better at 45,000 plants per acre.
Consider it as food for thought when you're talking to your seed rep about hybrids and response to population.