Give Each Rice Seed A ″Healthy Start″

Date:07-26-2023

″The ricefields’ sweet smell promises a bumper year. Listen, how frogs’ croaks please the ear.″ Now is the season to grow rice, which is one of the main staple crops in China and even in the world, and also the main model species of monocotyledonous plants and crops research. Rice seed is the basis to ensure the growth and development of the crop and its high and stable yield. The preservation of seeds and seedlings is the key in agricultural planting. 

Seed coating agents can be described as the ″guarantor″ to ensure the normal germination of rice seeds. They can be precisely applied to the seeds in a targeted manner and coated on the surface of the seeds precisely through advanced film-forming technology, which can eliminate seed-borne and soil-borne pests and diseases at the start of growth, mitigate pest and disease control pressures at intermediate and reduce costs for farmers at last.

What are the main factors that affect the germination and healthy growth of rice seeds? Firstly, temperature is a key factor affecting the germination of rice seeds. The optimal germination temperature of rice seeds is 25-30℃. When the temperature exceeds 35℃ or falls below 15℃, the germination rate of seeds will be significantly reduced or the germination will stop. In general, the higher the temperature and the higher the humidity, the faster the germination of rice seeds.

Secondly, water is an indispensable factor in the seed germination process, and the water required for rice seed germination is about 50–60% of the dry weight of the seed. If there is too much water, the seeds will rot. Too little water will prevent the seeds from germinating. Generally, rice seeds germinate best when the moisture content is 20%–25%.

Thirdly, as the germination process of rice seeds requires oxygen, the level of oxygen around the seeds will also affect their germination. If there is insufficient oxygen, the seeds will not germinate normally, and will even suffocate to death. When seeds germinate in a hot and humid environment in summer, they tend to consume a lot of oxygen. Fourthly, soil conditions: Soil pH, fertility, texture and other conditions will also directly affect the germination of rice seeds. Factors such as too high or too low a soil pH or too low fertility will affect the germination of seeds.

To increase seed germination rate and promote growth, the first treatment is seed coating. At present, the main rice seed treatment products of Sinochem International Crop Care are Oukai (63g/L Metalaxyl • Fludioxonil) and Youshuai (25% Thiamethoxam • Fludioxonil • Metalaxyl), all of which use Sinochem’s patented film-forming agents, which can not only ensure the water permeability of the seeds, but also can effectively coat the liquid around the seeds to reduce liquid loss. In recent years, more and more rice growers have chosen seed coating. Seed coating agents not only play a strong protective role, but also promote the emergence of seeds. Rice seed coating has the following advantages:

1. Promoting the development of seedlings and the root systems: Compared with blank control, coated seeds enjoy a higher seedling emergence rate, more robust seedling growth, a more robust and developed root system, and a higher leaf spread.

Figure 1: Comparison of rice emergence after coating with Oukai

2. Effective disease control: Coated seeds can effectively control bakanae disease, seedling rot, cataplexy, thrips and other diseases and pests, mitigate pest and disease control pressures at intermediate, and reduce costs for farmers, thereby guaranteeing rice production.

3. According to the survey, compared with those of uncoated rice seeds, the germination rate of coated rice seeds increased by 2 to 5 percentage points; the seedling survival percentage increased by 5 to 8 percentage points; the number of tillers per plant increased by 0.5 to 2; the total number of roots per plant increased by 2 to 6; and the number of white roots increased significantly.

Figure 2: Comparison of root systems of Oukai-coated rice

4. Trace elements such as manganese, zinc, copper and boron can also be added in the seed coating solution according to different planting needs, which can provide trace elements to rice in a timely and effective manner, promote rice growth, help make rice roots strong, and enhance stress resistance, thus achieving stable and high yield.

Seed coating, as a high-efficiency, seed-saving, agent-saving, and labor-saving process, provides a lot of convenience for rice production. When sowing the coated seeds, the sowing operators only need to protect themselves to avoid the adverse effects of agents on the human body. However, before sowing, in order to ensure that the agents on the seed will not lose and dust off, the following points still deserve attention:

1. Pay attention to the local weather when coating. Choose the weather with moderate humidity and temperature for coating. Too low temperature or too high humidity will affect the coating effect.

2. When coating, the seed temperature should not be too different from the temperature of the coating environment or the coating agent, otherwise a water vapor film will be formed between the seed and the coating agent, affecting the coating effect and leading to dusting-off later.

3. The surface of the seed after coating has not completely formed a film, and it needs to be left to dry when it is not completely dry. Excessive rubbing, shaking or soaking the seed immediately after coating will lead to the loss of some agents.

While rice seed coating agents brings convenience, there are also some hidden dangers when they are used. At present, one general problem is that the germination potential of coated seeds will be reduced when they are subjected to low temperature stress. This phenomenon is not common in the non-low temperature environment. It is generally believed that this is because some components of the agent are bound too close on the seed coat surface, hindering the absorption of water, oxygen and other substances, and extending the time it takes the seed to break the dormancy period. This phenomenon is more obvious in dry seed coating and less obvious in soaking seed coating.

In response to low temperature stress faced by coated seeds, the problem of film-forming agents should be solved first from the perspective of seed coating agent. As a bridge between the agent and the seed, the film-forming agent is like a double-edged sword. Too tight binding with the seed coat will affect seed germination; too loose binding will lead to agent loss.

At present, the seed coating agent of Sinochem International Crop Care is capable of ensuring the normal respiration of seeds while ensuring the retention of agents on their surface. This relies on the patented film-forming agent technology of the company. A large number of experimental data shows that the germination potential of rice seeds coated by the solution of Sinochem International Crop Care is almost the same as that of uncoated seeds, and their germination rate is higher than that of uncoated seeds. Adding some plant nutrients to seeds can also improve this condition. For instance, gibberellin can break seed dormancy at seedling stage; amino acids can promote the root system growth of the plant, strengthen seedlings and plants, and enhance the photosynthetic function of leaves and the ability of the crop to resist pests and diseases. Nitrogen, phosphorus, potassium, iron, copper, manganese, zinc, aluminum, boron and other essential elements for plant growth can supplement enough nutrients for plants at the seedling stage. In addition, attention should be paid to avoid low temperature weather when growing seedlings, so as to avoid the impact of low temperature when seeds germinate.

All of the above means can protect the coated seeds from the impact of low temperature stress, but the most important thing is to select seed coating products from well-known manufacturers such as Sinochem International Crop Care, which can ensure higher effective content and purity in the agent while avoiding the damage of hidden ingredients to seedlings and seeds.

To address issues such as low temperature and bakanae disease in current rice seed coating, it is recommended to select the rice seed coating agents containing Metalaxyl + Fludioxonil, such as Oukai (63g/L Metalaxyl • Fludioxonil) and Youshuai (25% Thiamethoxam • Fludioxonil • Metalaxyl) made by Sinochem International Crop Care.

Moreover, according to the variety characteristics and planting needs of different seeds, similar substances such as amino acids and essential elements can also be added to the seed coating solution, or other pesticides and fungicides can be combined. Such addition and combination can provide all-round protection for seeds and seedlings and supplement the nutrients required for their growth and development, thereby achieving all-round tracking of protection - seedling strength - high yield.

By focusing on its ″4S Strategy″ for its seed coating business, Sinochem International Crop Care will provide innovative, cost-effective, complete and supportive seed treatment solutions to ensure the all-round care of crops, from seed germination to later growth process, as well as to improve the value of seeds and create a ″chaser″ in China’s seed coating sector, thus guaranteeing yield boost for farmers.

SOLUTION: Target the defects of seed varieties and weaknesses of pest and disease control, highlight the effectiveness and safety of product solutions, and in response to the challenges and weaknesses in the control of seed-borne and soil-bore pests and diseases, formulate new coating agent product R&D plan in product composition, film-forming agents, and bioactive substances with stress resistance by combining patented compounds and expanding their use.

SAVE: Continuously optimize the production process and the product formula to improve product quality, focusing on meeting customers’ needs, providing them with cost-effective solutions, and helping seed sectors and large-scale growers to improve quality with reducing use rate and costs.

SERVICE: Sinochem International Crop Care will provide the comprehensive value-added services based on customers’ needs and introduce all-around ″product + service″ measures for ″Seed Coating Agents +″ by providing technical guidance and offering plant protection and nutritional products after emergence, as well as smart agriculture services across the whole industrial chain.

SYNERGY: By continuously strengthening the internal and external collaboration and industrial synergy of parent company Syngenta Group China, Sinochem Crop Care will evolve into the strongest comprehensive platform for seed services in China.

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This article was initially published in AgroPages' '2023 Seed Treatment Special' magazine.

If you would like to share your company's story. Please contact Christina Xie at christina@agropages.com

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