The ear of corn is one of the most beautiful parts of the plant. But, there are some unusual things that can happen to it. Let’s look at some of the most common abnormalities.
Pollen sheds from the tassel onto the silks
The pollen shed from the ear of corn tassel is an important part of the process of pollination. Depending on the hybrid, pollen shed may last five to eight days.
Pollen is a light and airy substance that is carried by wind up to one mile. Corn pollen is yellow in color and contains male genetic material. During a rainstorm, only small amounts are washed off the silks.
In a field of corn, each plant can produce between two million and five million pollen grains per tassel. This is a relatively small number compared to the number of kernels produced by each plant.
Pollen tubes grow inside the ovules
The pollen tube is a tubular structure that acts as a conduit for the transport of male gametes from the pollen grain to the ovule. In the case of a flowering plant, a single pollen tube can grow up to 12 inches (30 cm) in diameter and deliver two sperm cells to the ovule.
The pollen tube is an important model for understanding plant cell behavior. The cytoskeleton of the pollen tube provides a dynamic structure that can rapidly change direction to accommodate changes in orientation. This process is referred to as elongation.
Pinched ear symptom
Abnormal ears of corn may occur due to a range of environmental, physiological, and chemical stresses. These disorders can affect the quality and quantity of corn grain, and the resulting yields. Understanding the cause of abnormal ears can lead to better mitigation and crop resiliency, and can help farmers and other stakeholders improve their farming systems.
The most common form of abnormality, pinched ear, results from reduced number of kernel rows from the butt to the tip of the ear. In some cases, whole rows of kernels are absent. This symptom is most often caused by sulfonylurea herbicide injury, and has been associated with soil-applied organophoshate insecticides.
Fasciated ear
When corn ear development becomes abnormal, it is detrimental to the grain yield. It also can affect the quality of the grain. Understanding the underlying cause of abnormal ear formation can help with mitigation and crop sustainability.
Abnormal ear development is a response to complex interactions between genetics, environment, and management practices. These factors play a role in both short-term and long-term variability. As such, it is imperative that ear development be a part of the breeding program decision-making process.
Several colloquial terms are used to describe abnormal ears of corn, such as branched, pinched, and arrested ears. The causes of each symptom are unclear and need further research.
Tipped-back ears
The latest issue for many growers is tip-back, or the lack of kernels filling the end of a corn ear. Many seed companies are reporting an unusually high number of tipped-back ears this year. Typically, a tipped-back ear resembles an empty cob sticking out of the husk, a symptom of poor pollination or intense plant competition.
There are many different reasons for a tipped-back ear. One of the most obvious is lack of water during the early days of pollination. Another is inadequate nutrients. A dry climate can slow silk development and delay the emergence of a tipped-back ear.
Incomplete kernel set
A corn ear with an incomplete kernel set refers to a corn cob where the husk and kernels are not fully developed. This may occur in fields with favorable growing conditions. The missing kernels are usually restricted to one side of the ear.
Incomplete kernel set can be caused by several factors. These include heat/drought stress, insect silk clipping, and ineffective pollen.
Incomplete kernel set is usually the result of a failure to fertilize the ovules with pollen. Pollen must be present when the tip silks emerge from the husk. When the silks fail to reach the ovules, ovules will abort.
Abnormal ear development
Abnormal ear development in corn is a common problem that affects nearly all plants. It is caused by stress during ear development. Some of the signs of abnormal ear development include multiple ears on the same plant and reduced kernel row numbers.
Corn ear development typically begins at V5 growth stage. This stage is critical for developing the ear and determining the maximum number of kernels that can be produced. In addition, it determines the length of the ear. After the emergence of silk, the number of kernels can increase or decrease depending on the environment.
