The 2021 growing season may be completely different than 2020. Still, notes and observations made in 2020 can help reaffirm things we thought we knew, and perhaps point to new information.
Here are 15 observations from my plant breeder’s notebook from 2020. Several were made in the Corn Watch ’20 field in central Indiana.
1. Very young corn can withstand a 27-degree-F freeze. Most corn already planted was just emerging or very small during the Mother’s Day weekend freeze. It continued growing when temperatures warmed up.
2. Plants that emerge within the first two days of each other perform equally. These plants showed little difference in ear weight. However, ear weight tends to slip for plants emerging three to four days after the first plants emerge.
3. Every plant tries to produce. Even a plant that struggles will try to produce an ear with one or more kernels, which are its progeny.
4. Unexplained streak patterns in fields early may disappear later. These could be from traffic patterns from previous years. Lighter-colored corn within these streaks were lower in nitrogen when tissue samples were pulled.
5. Stage corn growth to know when to pull tissue samples. When you stage growth at V12, determine which leaf to start counting with. Some initial leaves have already disappeared.
6. Soil compaction effects will not disappear in one year. This is true even if the compaction was caused by a person walking in the field when it was wet. Early rains followed by late dry weather turn high-clay soil into concrete. We could not pull out wire flags. That is incredible!
7. Different rows may emerge at different times. This is especially true after a heavy rain. The cause was undetermined, but it builds a case to check emergence and spacing row by row.
8. Late emergers or abnormal corn plants become weeds. They draw inputs away from normal plants. The truth is, they’re worse than weeds, because they’re resistant to corn herbicides.
9. Plants will likely show signs of nutrient deficiency near black layer. Ideally, try to identify the symptoms of deficiencies and try to determine if nutrients ran short before black layer. This might help you plan for next season.
10. Scouting for diseases pays dividends. To be sure about your diagnosis, send leaf samples to university labs for positive identification.
11. Timely fungicide application protects yield. We were able to diagnose gray leaf spot and inform the farmer, who had foliar fungicides applied right away and stopped the disease in its tracks. However, it’s difficult to judge precisely how much fungicides help when there are no check strips in the field.
12. Tip kernel abortion can vary. This can change from one spot to another within a field, and perhaps from hybrid to hybrid. Heat and drought stress can affect hybrids differently.
13. Number of kernels rows per ear is hybrid-specific. However, depth of kernels can vary by hybrids.
14. You can find three different rots on one ear. We saw diplodia, gibberella and aspergillus infecting one ear. However, this doesn’t mean mycotoxins were produced.
15. Kernel size matters. Corn yield estimates can vary significantly based upon what you use as the fudge factor for kernel size in the yield formula.
Nanda is director of genetics for Seed Genetics Direct, Jeffersonville, Ohio. Email email@example.com or call 317-910-9876.