A few weeks ago Dave Nanda took red and pink thread to the corn field and tied it on various stalks to mark them for observation. He picked out a spot with normal spacing, a spot with spacing that was narrower than normal, and a spot where spacing was wider than normal.
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Since there were two hybrids planted in the Crop Watch Field, he repeated the procedure in both hybrids. Since it was a demonstration, not a replicated experiment, he only did it once.
When he returned recently, he harvested the three ears on each hybrid. Then he counted rows and kernels per row.
For hybrid A, the wide, normal and narrow spaced stalks produced these ears: 16 rows, 38 kernels per row; 16 rows, 38 kernels per row, and 16 rows, 35 kernels per row, respectively.
For hybrid B, the wide, normal and narrow spacing was: 18 rows, 43 kernels; 18 rows, 34 kernels; and 16 rows, 35 kernels.
"There are some lessons here," says Nanda, consultant for Seed Consultants, Inc. The company is sponsoring prizes of free seed corn for 2016 in the Crop Watch contest.
"First, there are differences in hybrids," he begins. "Hybrid A performed about the same no matter whether stalks were spaced evenly, too wide or too narrow. It's highly likely it's a hybrid that doesn't flex much even when population varies.
"Hybrid B does flex ear size. The long ear at the wide spacing indicates as much."
Second, Nanda says, crowding can have an impact. "It was less evident on Hybrid A. But for hybrid B the crowded ear had fewer rows and was slightly shorter. Fewer rows can be a result of crowding as well."
Third, crowding can result in more kernel abortion. "The crowded ear on Hybrid B was still a decent ear, but there was a long, barren tip. It would have had many more kernels if it had filled.
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"The way the plant operates, it sensed it didn't have enough resources to fill those tip kernels so it aborted them. It concentrated on making good kernels of those it could fill. Plants are always driven to produce as many viable progeny as possible."