Scouting can't explain every 'runt' plant

August 20, 2020

Dave Nanda, Ph.D., SGD director of genetics, has seen almost everything in nearly 60 years of working with corn. When scouting, few things happen in a cornfield that he can’t explain. Yet, now and again, even Nanda can only guess and suggest theories.

For example, in the Corn Watch ’20 field, planted May 13, plots to monitor emergence were set up across 10 adjacent rows. Then, each plant in 1/1,000 of an acre was flagged with an appropriate color of flag, depending on which day it emerged: blue flags marked plants that emerged two days after the first plants, green flags marked plants that emerged four days after the first plants.

Earlier in the summer, Nanda found a plant with a green flag that was struggling to exist. Its diameter was much smaller than the plant marked by a blue flag next to it, and it was several growth stages behind.

“Although it emerged two days later than the plant with the blue flag, two days difference in emergence, especially at that point in the season, should not result in that kind of difference in stalk height, diameter and amount of growth,” said Nanda. “If we could have dug up the plant, we might have found more clues in the roots. But, the goal was to monitor the emergence plots all season, so we didn’t want to dig up any of the plants.”

However, Nanda suspects that perhaps the plant had trouble emerging, even though it was above ground only two days after the plant next to it, and only four days after the first plants emerged in the field. Perhaps the area where it emerged was more compacted, even though it was only inches from other plants.

“That’s why we talk about microclimates,” Nanda said. “If it was just a touch wetter and it compacted more at that point in the row, it might have affected the plant. Perhaps the seed went deeper than other seeds and that affected emergence.

“The truth is, we can’t always explain what happens to every plant. They are living things, and sometimes things just happen. Yet scouting allows us to pick up trends.

“One thing we know is that the plant by the green flag will probably become a weed. If it survives to harvest, it will likely be barren. We will watch it to find out.”

The Corn Watch ’20 field is sponsored by Seed Genetics Direct. Reports on the field’s progress are provided all season (#CornWatch20); read the latest Corn Watch ’20 articles here. Stories are written by Tom Bechman.