Selecting Hybrids

Corn hybrid selection depends on the farming operations. Plant corn early and use early-season hybrids if you plan to harvest early. Choose full-season hybrids if you plan to harvest late in the season. Planting different maturities at different times helps to spread the planting and harvest operations.

Choose hybrids that produce consistently high yields across multiple locations and years. However, the selection should not only be based on the yields, but also lodging, which may severely decrease yields under certain situations. Consider varieties with good tolerance to insect sand diseases, and good grain quality. If the feeding or other values are important, check the protein and oil composition of corn grain. Select hybrids with high grain protein for feeding and high oil content for processing.

Hybrid selection should be based on:

  • Maturity – appropriate for location and farming operations. Selecting 2-3 different maturity groups can help to minimize the adverse effect of weather conditions, and spread planting and harvesting operations.
  • Yield – high yielding hybrids over multiple locations and years should be used. The hybrids are evaluated annually in official Clemson University tests and results are posted on the web site at
  • Stalk strength – good stalk strength helps to minimize grain yield losses due to lodging.
  • Disease and insect tolerance – select varieties with good disease and insect resistance.
  • Grain quality – choose hybrids with good grain quality.
  • Select hybrids with high digestibility if used for silage.

Corn producers should plant different maturity corn to minimize the adverse effect of weather conditions and reduce risk. Corn maturity is described as Relative Maturity (RM). However, the actual days to maturity will depend on the time of planting and seasonal weather changes. More accurate determination of days to maturity can be calculated based on the GDD.

Due to changes in temperature, the actual number of GDDs experienced for any given period will vary from year to year. Kernel moisture content at physiological maturity generally averages about 30 to 35%. At physiological maturity a "black layer" will form under the outer layer of the kernel tip. When this forms, it signals that kernel dry matter accumulation has reached the maximum level.