GENETIC DIFFERENCES
Todd Burrus of Illinois-based Burrus Seed Company wrote on August 24, 2022 that now is the best time to see the tips before the ears and tips start to shrink next month during drying. “The reality is that the plant is expected to take in more cores than it can complete…Not all cores will make it to the finish line,” he wrote.
The hybrids will also show genetic differences to stress, he said. And the moment of key stress can trigger different responses. “Keep in mind that if that stress point is removed, the product with the most backward tips may have been the winner in other places or seasons. Imagine two people running in the heat. One will inevitably go further than the other. The reasons of this can be unlimited,” he said.
High-yielding growers will even say they leave the yield on the table if the ears are completely stuffed to the top. A half-inch or so of tip back can be a sign that plant populations are ticked for some growers, Quinn agreed.
Still, Quinn urges all farmers to get out there and pull out some ears to check on the grain-filling progress.
COUNTING CORE
“After doing some yield evaluations, farmers might be surprised at how much is available, even if they see a tip,” Quinn said. “Ear size is determined around V6 to V15 or up to a few weeks before pollination. Many of those fields that were challenged this year may still have some decent ear sizes.
“The lost yield potential for each missing kernel per row in an 18-row corn hybrid (assuming a final ear count of 28,000 ears per acre), equates to about 6 bushels per acre,” Quinn said. “So yes, the performance loss from sterile tips can add up.”
However, he points to a bulletin (https://www.agry.purdue.edu/…) written by Bob Nielsen, corn specialist emeritus at Purdue University, indicating that the kernel count for ears harvested from many hybrids is about 600. Hybrids whose ears are typically 16 rows in circumference tend to set about 36 to 40 kernels in each row, while those that typically develop 20 rows of kernels around tend to set about 30 kernels per row.
“If the potential ear size (number of ovules) was large enough prior to pollination (favorable pre-pollination conditions) but failed to pollinate the tip silks, the resulting ears may still exhibit 30 to 40 kernels per row, even though there is 1 or 2 inches of barren tip. In other words, the harvested ear size will still average about 600 kernels, and the final kernel yield will be average or above average.
“On the other hand, if the kernel counts show only 20 to 25 kernels per row with long sterile ear tips, that indicates the crop suffered significant stress conditions, probably more than once during the season. per ear will be much less than 600, and the final grain yield in this latest example will likely be less than the average for that field and/or hybrid,” Nielsen wrote.
WHATS NEXT?
There is no way to improve grain numbers this late in the season. The question is what happens now with what is left. “Hopefully the temperatures will behave and we can extend that grain-filling period a little longer to keep filling what’s there,” Quinn said.
Monitoring fields with tips from now until harvest is a good idea, Burrus added. Plants that have few resources for full reproduction often steal these resources from the rest of the plant and compromise stability.
For more information on tip refunds, visit: https://www.dtnpf.com/….
Pamela Smith can be reached at [email protected]
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