Propagation of improved varieties of soybean

Soybean is a self-pollinating crop, which often becomes worse due to mechanical mixing, bad climate and cultivation conditions, as well as natural hybridization and other reasons. Therefore, self-bred seeds should not be used for a long time and should be replaced every three years. Therefore, we must persist in purification and rejuvenation and do a good job in breeding in order to maintain the breed character of fine varieties.

1. Methods of purification and rejuvenation of soybean varieties.

The main results are as follows: (1) the common method of soybean purification and rejuvenation is composed of three steps: single plant selection, strain identification and mixed high-power reproduction. There are three nurseries: single plant selection nursery, plant comparison nursery and mixed breeding nursery.

Single plant selection nursery: typical excellent single plant was selected for seed examination, and single plant was threshed. Eliminate the individual plant which is inconsistent with the grain color, grain shape, navel color and other characters of the original variety.

Strain identification nursery: each single plant is planted in a row (line). Eliminate lines that are inconsistent with the original varieties. The planting design can adopt a pair of rows every 10-20 rows (the original variety). Select the strain and breed next year.

Mixed breeding nursery: the seeds identified and harvested by the above-mentioned strains were planted evenly and sparsely on demand, and the seeds were propagated at high times.

The seeds produced by the above three nurseries are called the super original species of purification and rejuvenation.

(2) mixed seed selection when soybean is mature, a certain number of robust and excellent individual plants with typical characteristics of this variety are selected, then strictly checked in the laboratory, then mixed threshing and preserved separately, which can be used in the breeding field next year. The breeding field adopts advanced cultivation and management measures, and strictly removes the miscellaneous and inferior.

(3) an excellent single plant with typical characters of the original variety was selected by one plant, and its offspring were carefully cultivated and propagated. In this method, the seeds harvested by single line are expanded and propagated, and the life span of this method is slightly longer than that of line selection.

2. Establish seed field.

The super original seeds of soybean obtained by purification and rejuvenation need to establish seed fields and reproduce a large number of seeds because of the small number of seeds.

The area of seed field is determined by the number of seeds sown and the yield per mu of seed field. In general, the seed field area is 4% of the production field or 5% of the seed field area of the next higher level. In the selection of seed field plots, the plots with flat terrain, good drainage, uniform soil fertility, non-stubble and non-stubble should be selected. Increase the application of farm manure and apply chemical fertilizer according to the ratio of nitrogen and phosphorus. Strengthen field management, and time seedlings, timely ploughing, weeding and soil cultivation, so that the soil is loose and free of weeds. During flowering and grain filling, topdressing 1-2 times, timely irrigation during drought, timely prevention and control of diseases and insect pests. In the whole growth period, according to the morphological characters, seedling stage, flowering stage, mature stage, strictly remove miscellaneous and inferior. After maturity, timely harvest, strictly grasp the harvest, threshing and other links that are easy to cause mechanical confusion.