Detailed Explanation of Key Points of Soybean Good Seed Propagation Technology

Soybean is a self-pollinating crop. Due to mechanical mixing, adverse climatic conditions and cultivation conditions, as well as natural hybridization and other reasons, seed quality often deteriorates. Therefore, self-pollinated seeds cannot be used for a long time, and seeds should be replaced every three years. Thus, it is necessary to persist in purification and rejuvenation and to do a good job in good breeding work in order to maintain the seed quality of superior varieties.

1. Methods for purification and rejuvenation of soybean varieties

(1) Line selection The commonly used method for soybean purification and rejuvenation consists of three steps: individual plant selection, line identification, and mixed high-multiplication propagation. Three fields are set up separately: an individual plant selection nursery, a line comparison nursery, and a mixed propagation nursery.

Individual plant selection nursery: Select typical superior individual plants for seed testing and thresh individual plants separately. Eliminate individual plants whose traits such as seed color, seed shape, and hilum color are inconsistent with the original variety.

Line identification nursery: Plant each individual plant into 1 row (line). Eliminate lines inconsistent with the original variety. For the planting design, one control row (the original variety) may be planted every 10-20 rows. Selected lines are used as propagation seed for the next year.

Mixed propagation nursery: Sow the seeds obtained from the above line identification and mixed harvest at equal spacing and sparse planting for high-multiplication propagation.

The seeds produced through the above 3 nurseries are called purified and rejuvenated super stock seeds.

(2) Mixed selection When soybeans mature, select a certain number of robust and superior individual plants with the typical characteristics of the variety, then undergo strict indoor re-selection, then thresh them together and store them separately as seed for the next year's propagation field. The propagation field adopts advanced cultivation and management measures and strictly removes impurities and inferior plants.

(3) Single-plant transmission Select superior individual plants with the typical traits of the original variety and carefully cultivate and propagate their progeny. In this method, seeds are harvested from a single line and expanded for propagation, and the time required is slightly longer than that of the line selection method.

2. Establishing a seed field

Because the amount of soybean super stock seeds obtained through purification and rejuvenation is very small, it is necessary to establish a seed field to massively propagate seeds for production use.

The area of the seed field is determined by the amount of sowing seed and the yield per mu of the seed field. Generally, the area of the seed field may be 4%-5% of the area of the production field or the next higher-level seed field. For the selection of the seed field plot, choose a plot with flat terrain, good drainage, uniform soil fertility, and no continuous cropping or back-to-back cropping. Apply more farmyard manure and apply chemical fertilizers according to the nitrogen and phosphorus ratio. Strengthen field management, thin seedlings in time, cultivate and weed at the right time, and earth up to keep the soil loose and free of weeds. During the flowering and pod-filling period, apply topdressing 1-2 times, irrigate promptly during drought, and prevent and control pests and diseases in time. During the entire growth period, strictly remove impurities and inferior plants according to morphological traits at the seedling stage, flowering stage, and maturity stage. After maturity, harvest at the right time and strictly manage the links prone to mechanical mixing, such as harvesting and threshing.