GENETIC CHANGES
Todd Burrus, with Illinois-based Burrus Seed Company, wrote on August 24, 2022, that now is the prime time to look at the tip before the ears and tops start to shrink in the next month during drying. “The reality is that the factory is expected to support more cores than it can finish … Not every core will make it to the finish line,” he wrote.
Hybrids will show genetic changes to the stress as well, he said. And the timing of key stress can trigger different responses. “Realize if that stress point is eliminated, the product with the longest tip back may have been the winner in other countries or seasons. Imagine two people going for a run in the heat. One will inevitably go further than the other. Reasons that’s why it can be limitless”, he said.
High yielding growers will even say they leave the yield on the table if the ears are completely filled to the top. A half-inch or more of tip back can be a sign that plant populations are dialed in for some growers, Quinn agreed.
However, Quinn asks all farmers to come out and pull a few ears to check the progress of core filling.
COUNTING KERNELS
“Farmers might be surprised after they do some yield estimates of how much is out there, even if they see some tips,” 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 suitable 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), equals about 6 bushels per acre,” Quinn said. “So yes, yield loss from barren tips can add up.”
However, he points to a bulletin (https://www.agry.purdue.edu/…) written by Bob Nielsen, Purdue University corn specialist emeritus, that shows that the number of kernels for harvested ears of many hybrids is approximately 600. Hybrids whose ears are typically 16 rows in a circle tend to place about 36 to 40 kernels in each row, while those that typically develop 20 rows of kernels around tend to place closer to 30 kernels per row.
“If the potential size of the ear (number of eggs) was large enough going into pollination (favorable conditions before pollination) but failed to pollinate the tip silk, the resulting ears may still display 30 to 40 kernels per row even though there are 1 to 2 In other words, harvested ear size will continue to average around 600 kernels and the final grain yield will be average to above average.
“On the other hand, if the kernel count shows only 20 to 25 kernels per row with long barren ear tips, then that really indicates that the crop has suffered significant stress conditions, perhaps more than once during the season. The number of kernels per ear will be much less than 600, and the final grain yield in this last example will likely be less than average for that field and/or hybrid,” Nielsen wrote.
WHAT DO YOU EXPECT NEXT?
There is no way to improve the kernel numbers this end of the season. The question is what happens now with what is left. “Let’s hope the temperatures come around and we can extend the grain fill period a little bit longer to continue to fill what’s there,” Quinn said.
Monitoring tip fields between now and harvest is a good idea, Burrus added. Plants lacking resources for full reproduction often rob these resources from the rest of the plant and compromise viability.
For more information on tipping, go to: https://www.dtnpf.com/….
Pamela Smith can be reached at [email protected]
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