The Best Time for Topping Sesame and a Detailed Explanation of Key Precautions

Sesame is an important economic crop in China, grown over a wide range. During cultivation, topping is often carried out to increase yields; common crops that require topping include tomatoes, cotton, and tobacco. So does sesame need topping? When is the best time to top it? Let's find out together.

1. The role of topping sesame

In the early stage, sesame leaves are thick and broad, and in the later stage the leaves change from heart-shaped to lanceolate. Through photosynthesis they consume nutrients, which has a certain effect on the seed-setting rate and quality of sesame, so appropriate topping is needed. Topping can optimize the growing environment of sesame, regulate the plant's nutrient distribution, reduce ineffective consumption of nutrients, and promote the reproductive growth of sesame. Extending leaf photosynthesis can increase the seed-setting rate and the plumpness of the grains, with an obvious effect of increasing both yield and quality.

2. Timing of topping sesame

The timing of topping sesame must be well controlled. Topping too early will reduce the number of capsules and the number of photosynthetic leaves, while topping too late will fail to achieve the goal of regulating nutrients, leading to an increase in the number of ineffective capsules. Generally, topping is carried out after 60 days, and the best period is at 25-30 days, that is, three weeks after the first flowering. The specific time depends on the variety, season, and climatic conditions. Generally, autumn-cultivated varieties can be topped 24 days after flowering, while summer-cultivated ones are usually topped 25-30 days after the first flowering.

3. Precautions for topping

Although sesame can be topped, picking leaves is prohibited. In some sesame-growing areas, farmers pick sesame leaves for use, which causes a yield reduction of about 20%-30%. In the functional leaves at the capsule-bearing site after the first flowering, the products of sesame photosynthesis are transported and distributed most to the side capsules, next to the lateral ones, and very little transversely. Therefore, sesame after leaf picking will have reduced plumpness of the capsule grains and poor quality, so picking leaves must be prohibited.

4. Plant growth regulators

During crop cultivation, some plant growth regulators are used to ensure yield. For example, for topping cotton, flumetralin is used; for sesame, chlormequat, triiodobenzoic acid, and others can also be used, which can effectively increase yield and reduce the rate of shriveled grains. However, the paclobutrazol used in crop production has no yield-increasing effect on sesame and cannot replace topping.

The above is an introduction to the timing of topping sesame and the precautions to take. We hope it helps you. For more related knowledge, please stay tuned to us.