Hybrids with poor stalk quality should be avoided for grain production even if they show outstanding yield potential. Hybrid stalk quality as measured by stalk lodging (stalk breakage below the ear) at harvest has improved greatly over the last 20 years. Nevertheless, this trait is particularly important in areas where stalk rots are perennial problems, or where field drying is anticipated―i.e., conditions that often lead to lodging. If growers have their own drying facilities and are prepared to harvest at relatively high moisture levels (above than 25 percent) or are producing corn for silage, then standability and fast drydown rates are less critical selection criteria.
Traits associated with improved hybrid standability include resistance to stalk rot and leaf blights, genetic
stalk strength (a thick stalk rind), short plant height and ear placement, and high staygreen potential. Staygreen refers to a hybrid’s potential to stay healthy late into the growing season, after reaching maturity, and should not be confused with late maturity. Resistance to European corn borer conferred by the Bt trait can also enhance stalk quality by limiting entry points in plant tissue through which fungal pathogens can invade the plant. However the Bt trait will do little to minimize stalk rot and lodging in a hybrid characterized by below-average stalk quality.
Another stalk-related problem, green snap or brittle snap has started to appear in recent years. Corn plants are more prone to snapping during the rapid elongation stage of growth when severe wind storms occur. According to studies in Iowa, Minnesota, and Nebraska, the V5 to V8 stages (corn approximately 10 to 24 inches in height) and the V12 stage through tasseling are the most vulnerable stages. Vulnerability to green snap damage varies among hybrids. However, all hybrids are at risk from wind injury when they are growing rapidly prior to tasseling. The use of growth regulator herbicides, such as 2,4-D or Banvel, has also been associated with stalk brittleness, especially if application is late or if application is made during hot, humid conditions occur. Once tassels begin shedding pollen, green snap problems generally disappear.