By Dr. Harold Willis
In this excerpt, biologist Dr. Harold Willis discusses how to choose the best corn seed and variety for your crops.
How to Select Corn Seed and Variety
First of all, you should always plant high quality seed with a high germination rate (above 98%). Seed quality depends partly on the health and vigor of the plant that produced it, as well as the care used in picking, drying, and sorting it. Seed grown under weather stress (drought, too wet, etc.) should be avoided.
It is very important to choose seed that is suited to your climate and soil, and for a desired maturation time. If you are growing corn for silage, choose a longer maturation time than if you want grain, since silage is harvested at an earlier stage of maturation. Another thing to remember is that 120-day corn, for example, may not mature in exactly 120 days. Growth can be slowed by unfavorable weather (too cold or too hot, drought, flooding) or nutrient deficiency, and it can be speeded up by optimal weather and soil nutrition, sometimes by as much as ten days to two weeks. A more exact way of measuring time to maturity is growing degree days (GDD). Growing degree days are calculated for each 24-hour day and added throughout the season.
The formula to use is:
If you don’t have a minimum-maximum thermometer, you can use figures from the nearest weather station. If the temperature goes below 50°F, substitute 50° for the minimum temperature, and if it goes above 86°F, substitute 86° for the maximum.
Seed should be chosen that contains desirable nutrient characteristics if you are growing grain or silage to feed animals. Among the hybrid varieties, there is a wide difference in protein quality and quantity. Most corn varieties are low in three essential amino acids, lysine, methionine, and tryptophan, so new hybrid varieties, generally called high-lysine corn, were developed. But they have their own problems: low germination and yield, and high moisture and kernel damage. Plus no hybrid contains as good a balance of trace minerals as open pollinated corn.
Other special hybrids include:
- waxy maize, which contains high amounts of amylopectin starch and is said to produce more efficient gain in beef cattle;
- high sugar corn (sweet-stalk corn), which is said to be good for silage, but it is lower yielding;
- high oil corn, which is said to be good for fattening hogs, although it produces a softer backfat; and
- upright-leaved corn, which uses light better when planted in close rows.
Many farmers are switching to open pollinated varieties. New methods for improving them are being developed. Different varieties have different characteristics; for example, white corn is high in carbohydrates, yellow is high in vitamin A, and colored (“Indian corn”) is high in minerals.
In general, higher test weight seed is of higher quality. To go through a planter well, seed should be graded for uniform size. Seed treated with fungicide and insecticide is good insurance, especially if your soil isn’t in ideal condition. Sometimes adding ordinary sugar to the planter box will take the place of fungicide treatment, plus stimulate soil bacteria.
Excerpt from How to Grow Top Quality Corn by Dr. Harold Willis