Yield is lost at harvest in fields with root lodging problems.
Root lodging occurs under saturated soil conditions when the entire corn plant is pushed over by strong winds. Hybrids with spreading, more-fibrous root systems are less prone to root lodging than hybrids having smaller, narrow-profile root systems. As a rule, genetic families that developed in areas with abundant moisture and/or where evaporation was slower, like cooler climates, tend to have smaller root systems because large root systems were not required for adequate moisture absorption. For this reason, the Eastern, Northern, Late Health and Early Health Genetic Families tend to have smaller-profile root systems, which make them more sensitive to root lodging.
The aggressive, early-season growth of Early Health and Late Health Genetic Families usually gives priority to leaf growth at the expense of root growth. The additional top growth will drive early flowering and increase yield potential by increasing the duration of grain fill. However, the shortchanged root system will make the plant more prone to root lodging and drought stress.
Performance limitations associated with smaller root systems can be aggravated through the use of phenoxy herbicides, which can injure the corn plant, especially the brace roots, and add even more stress to root development. Northern and Early Health Genetic Families are hypersensitive to phenoxies.
Using herbicide-tolerant systems, such as Roundup Ready® and LibertyLink® in Northern and Early Health hybrids, can reduce the herbicide injury risk. Generally, adding the High Yield Genetic Family to hybrids makes the largest, most fibrous root systems. Using hybrids with the High Yield Genetic Family in areas prone to root lodging or using corn rootworm corn can greatly reduce this risk. Because of a large, fibrous root system, hybrids with the High Yield Genetic Family make the best refuge hybrids for corn rootworm corn.
In addition to adding root lodging resistance, highly fibrous root systems also add drought tolerance to hybrids. Though High Yield Genetic Family hybrids tend to have slower seedling vigor, the production of more roots early in the season adds root lodging resistance and drought tolerance, which are important if it turns dry or if severe thunderstorms come through the area. This drought tolerance is favorable, unless seed is planted early in cool, wet soils, or the spring is unusually cool and wet.