Seeds must be carefully selected to bring out their vigor
Step 1: Improved seed processing
Seeds of superior varieties ≠ high-quality seeds
Good children come from a good mother; good seed makes good grain. The 10 premium corn seeds that can sell for 80 yuan, as mentioned by Wang Jianhua, professor at the College of Agronomy and Biotechnology at China Agricultural University, proves this truth. “This premium corn is not only a superior corn variety approved at the national level, but also grown from carefully selected ‘high-vigor seeds.’” Wang Jianhua said, “‘High vigor’ is the core competitiveness of seeds.”
, high-quality seeds among superior varieties = “high-vigor seeds.” Sun Qun, associate professor at the College of Agronomy and Biotechnology at China Agricultural University, gave a vivid definition of “high-vigor seeds.”
“Increase field emergence rate; resist adverse environmental conditions; strong cold resistance, suitable for early sowing; enhance competitiveness and resistance to pests, diseases and weeds; save sowing costs, facilitate field management; increase crop yield; improve seed storability.” Sun Qun listed one by one the production significance of “high-vigor seeds.” So, how are “high-vigor seeds” obtained? “Air selection, screening, specific gravity selection, color sorting and so on are currently several important means in China for improving seed quality (see table).”
According to Sun Qun, seed cleaning and selection is the core of seed processing. Its purpose is to remove extraneous matter in seeds (such as immature, broken, pest- and disease-damaged seeds and weed seeds) according to the physical characteristics of the seeds (such as width, thickness and length, density, critical suspension velocity, seed surface characteristics, etc.), and to separate seeds with high germination rates and vigorous vitality from ordinary crops to use for propagation, so as to improve seed quality, enhance the competitiveness of seed enterprises, and ensure the safe use of seeds in agricultural production. (Reporter Miao Yi)
Step 2: Variety regional trials
Product positioning trials take seed quality to the next level
Industry insiders have calculated an account: when sowing corn in the conventional way, the sowing rate is generally 2.5 kg to 3 kg per mu; if seed quality is improved and single-seed sowing is used throughout, 3800 to 4400 seeds are needed per mu, about 1.3 kg, saving about half the seed. Then, with about 500 million mu of corn planting area nationwide, if the saved half of the seed-production land were used to grow grain, it could solve the food problem of about 4 million people for one year.
But with single-seed sowing using less seed, how can uniform seedlings, strong seedlings and higher yields be guaranteed? Vigorously improving seed quality and enhancing seed vigor is the key!
“The quality of corn seed is the decisive factor in whether single-seed sowing can be carried out. Seeds that can be used for single-seed sowing require a germination rate above 95%, purity above 98%, and cleanliness above 99%. Moreover, the kernels should be plump and the sprouting vigor strong, and it is best if they are new seeds produced in the current year.” Dr. Sun Zhanyong, deputy general manager of Beijing Denong Seed Industry Co., Ltd., said, “‘PPT’ product positioning trials have provided comprehensive technical support for our company’s seed quality to reach a higher level.”
“The breeding of new varieties must go through regional trials (provincial or national) → production trials (provincial or national) → approval at the provincial or national level. According to relevant laws and regulations such as the national “Seed Law,” whether new varieties are bred by research institutions, seed companies or individuals, as long as they pass provincial or national approval, they can all be put on the market for sale and are all lawful business operations.” Sun Zhanyong said, “However, for lawful new varieties that have passed approval, we are not in a hurry to put them on the market for farmers to plant, but instead conduct our own new ‘PPT’ variety positioning trials, and promote and sell them according to the trial results.”
Sun Zhanyong and his technical team re-subdivide major crop regions such as corn, rice and sunflower nationwide every year, carry out targeted “PPT” variety positioning trials and provide technical services to farmers. At present, “PPT” variety positioning trials are carried out for crops such as corn, rice and sunflower, and all “PPT” trials have technicians personally sowing, investigating and harvesting. To determine a suitable trial site, technicians generally observe growth during the previous year’s corn or wheat growing season, judge whether the soil fertility is uniform and whether it is representative, and then communicate with farmers.
“At present, we have carried out ‘PPT’ trials for various crops in 21 provinces nationwide, achieving one site per 1 million mu in spring-sowing areas and one site per county or per 300,000 mu in summer-sowing areas. This year, as many as 362 trials have been arranged nationwide, covering 345 counties across the country, with each trial site area of 0.8 mu to 2 mu, capable of radiating coverage over 380 million mu of corn area, 120 million mu of rice area, and 5 million mu of sunflower area.” The “PPT” product positioning trials are probably Sun Zhanyong’s proudest achievement at present.
Advantages of seed cleaning and processing
Implementing seed cleaning and processing can not only improve the uniformity, cleanliness and thousand-kernel weight of seed kernels, significantly increase the seed germination rate and germination vigor, but also reduce seedling-stage pests and diseases and increase crop yields. In summary, it also has the following advantages:
Reduce workers’ labor intensity and improve work efficiency. Manual seed selection is not only labor-intensive but also inefficient, while mechanized cleaning and processing of seeds not only improves efficiency by dozens of times compared with manual work, but also results in stable seed quality after processing.
It is beneficial to seed storage and transportation. After seeds are cleaned and processed, diseased grains and living impurities mixed in the seeds are reduced, further improving seed quality and extending the seed storage period. Because seed cleanliness is improved and packaging sealing is good, losses caused by long-distance transportation and variety mixing or deterioration are reduced.
It increases the convenience of subsequent work. It facilitates seed coating, pelleting and precision dibbling, and improves work efficiency.
It improves the competitiveness of seeds in the market. After seed cleaning and processing, seeds are welcomed by farmers because of their high cleanliness and good quality.
Advanced methods of seed screening abroad
Color sorting. The principle by which color sorters separate seeds is: seed vigor is closely related to seed coat color. Generally speaking, the darker the seed coat color, the higher the seed maturity and the stronger the vigor. At present in China, color sorting is mainly applied to rice sorting and cottonseed selection, and its application to seeds of other crops is still very limited. Color sorters are developing very rapidly, from monochrome to bicolor, and now to full-color recognition technology. With market demand for high-quality seeds, the application of color sorters in the recognition and separation of seeds of other crops can be expected soon.
Liquid separation. A very traditional seed separation method. Compared with mechanical specific gravity separation, its separation effect is more precise. In the past, ordinary people in China knew to use salt water or muddy water for seed selection, selecting seeds with high specific gravity as sowing material. Seeds treated by this method need to be dried in time, which is relatively time-consuming and laborious. Liquid separation equipment developed in the Netherlands uses a special liquid as the separation medium. The liquid is volatile, causes no harm to seeds, and there is no problem of seeds absorbing water. After seed separation is completed, this liquid medium can be immediately recovered and reused.
X-ray separation. This technology is mainly applied to vegetable seeds. After seeds undergo priming treatment, their internal embryo structure can be directly observed through X-rays. Combined with computer image recognition technology, seeds with complete embryo structure, that is, high-vigor seeds, can be separated out. Its separation effect can reach about 1000 seeds per minute.