1.Physiological basis
After spraying Ethephon, Ethylene can be released in the plant, inhibiting cell elongation and increasing the lateral expansion of cells, thereby inhibiting the elongation growth of the stem.
In terms of enzymatic and hormone levels, Ethephon treatment significantly increased the activities of phenylalanine ammonia lyase and indole acetic acid oxidase in the basal elongating internodes, while the IAA content significantly decreased and the ABA content increased significantly. High, the GA1/ABA ratio is significantly reduced, which is considered to be the key reason why Ethephon inhibits the elongation growth of internode.
- Application effects and usage techniques
Spraying Ethephon when 1% of the plants in the corn field are tasseling can shorten the length of the basal internode, reduce the height of the ear, increase the stem thickness, and promote the development of the corn root system.
The ear height of medium-stem varieties is reduced by about 25cm, the stems are tough, and the number of aerial roots in the 8th to 9th layers is increased, which significantly enhances the lodging resistance of corn plants and increases yield.
The specific concentration used varies with different varieties. Sidan 19, a corn variety with a flat plant type, is more sensitive to Ethephon than Ping’an 18, a compact type.
The differentiation stage of corn female ears starts from the small trumpet stage, and reaches the large trumpet stage when the female ear is in the floret differentiation stage.
Therefore, some people suggested that on the premise of ensuring that the plant height is reduced and the lodging resistance is effectively enhanced, the application period of Ethephon should be postponed to the beginning of tasseling (1% of the plants are tasseling), so as to minimize the impact on the development of the ear.
Generally, when 1% of the plants in the corn field are tasseling, Ethephon 40%SL can be diluted to 2000~3000 times (approximately 133~200mg/L) for foliar spray treatment. The water consumption per acre is 25~30L.
- Precautions
Single use of Ethephon on corn has many side effects, mainly affecting the development of female ears, making the ears smaller, prone to tip baldness, reducing the number of kernels per ear, increasing the abortion rate, and reducing the thousand-grain weight.
It is not recommended to use Ethephon alone in production. At the same time, abortion of corn kernels mainly occurs 14 to 20 days after silking. When tasseling, the corn plant height exceeds the height of the human body.
Using Ethephon at this time not only increases the difficulty of technical operation, but also cannot completely avoid the negative impact of Ethephon on the development of the female ear.
Since Ethephon can significantly dwarf corn plants and prevent lodging, it is of great significance to be used in areas with frequent storms. In addition, when using Ethephon to regulate corn growth, appropriately increasing the planting density can lead to better yields.