Introduction to the soybean variety Nannong 88-31

Nannong 88-31 was developed by the Soybean Research Institute of Nanjing Agricultural University through crossing Suxie No. 1 as the female parent and 7303-11-4-1 as the male parent, followed by selection using the bulk-pedigree method.

Characteristics: Nannong 88-31 has a yellow seed coat, round seeds, glossy appearance, seed coat that does not crack, brown hilum, and 100-seed weight of about 20 grams. It has about 3 branches, a convergent plant type, and plant height of 110 cm. It has 40-50 pods per plant, with three- and four-seeded pods accounting for 35%, about 22 nodes on the main stem, pod-setting height of 22 cm, and sub-determinate pod-setting habit. Purple flowers, brown pubescence, elliptical leaves, good leaf drop, relatively resistant to lodging, and pods do not shatter at maturity. It is generally sown in mid to late June, flowers in early August, and matures in early to mid October, with a whole growth period of about 118 days, belonging to the medium-maturity summer soybean variety. According to identification by the Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, the field soybean mosaic virus disease severity of Nannong 88-31 is generally grade 0-1, and with indoor artificial inoculation of the prevalent strong virulent strain Sa in Jiangsu, the disease incidence is 0, making it a highly resistant variety. Field downy mildew is grade 1, and under indoor artificial inoculation conditions it shows grade 2, belonging to moderate resistance. Bacterial spot disease is grade 0-1 in field surveys and grade 1 under indoor artificial inoculation, belonging to high resistance. Under artificial infestation with the main leaf-feeding pests in the south, including Ascotis selenaria, Lamprosema indicata, and Spodoptera litura, the leaf damage rate of Nannong 88-31 is 23%, while the control variety has a damage rate of 36%, making it a moderately insect-resistant variety. In 1990 it was promoted to the identification nursery, with an average plot yield equivalent to 167.8 kg per mu, an increase of 39.4% over the then control variety Huaidou No. 2. In 1993, in the yield identification, the plot yield was equivalent to 182.8 kg per mu, an increase of 17.2% over the control Huaidou No. 2. In 1994, it participated in the multi-location identification of summer soybeans in the Huainan region of Jiangsu Province, with an equivalent yield of 138 kg per mu, an increase of 29.21% over the control Huaidou No. 2. From 1995 to 1997, it participated in the regional trial of summer soybeans in the Huainan region of Jiangsu Province, ranking first among the tested varieties in yield for 3 years, with an average yield of 172.99 kg per mu in the regional trial, an increase of 10.3% over the control Nannong 88-48. From 1997 to 1998, it participated in the summer soybean production trial, with a two-year average yield of 161.4 kg per mu, an increase of 4.96% over the control Nannong 88-48. In the 1997 high-yield trial, the yield reached 211.9 kg per mu, with the highest reaching 230 kg. Based on its promotion in Jiangsu, Anhui, Shanghai and other regions since 1997, this variety generally yields about 160 kg per mu and has a production potential of 230 kg.

This variety is a high-quality summer soybean variety with high fat content, high dry tofu yield, and high dry soymilk yield. The fat content is 21.7%, and the protein content is 40.13%-41.50%. Nannong 88-31 yields 73.59 grams of dry soymilk per 100 grams of dry beans, exceeding the control by 5.1%. The dry tofu yield is 53.8%, exceeding the control by 5.6%.

Nannong 88-31 began demonstration planting in production in 1997, and its variety coverage area includes Jiangsu Province and some cities and counties in the Huainan region of Anhui Province. As of 1999, it had been promoted cumulatively over 44.84 wan mu.

Breeder: Soybean Research Institute of Nanjing Agricultural University

Region and technology: This variety is suitable for planting as a summer soybean in Jiangsu, the area south of the Huai River in Anhui, and Chongming Island in Shanghai.

Cultivation procedures:

1. Sowing: The sowing period is mid to late June. Before sowing, seeds should be carefully selected, removing broken seeds and impurities. Sow at appropriate soil moisture according to soil type and moisture conditions; irrigation may be applied during drought, striving for full emergence in one sowing. The general seeding rate is 6-8 kg per mu, which can be done by manual dibbling or mechanical drilling, with row spacing generally 40-50 cm and plant spacing 10-13 cm. After emergence, thinning and final thinning should be done in time. The target stand is 1.2-1.5 plants per mu; if there are gaps, reseed or transplant seedlings promptly, as a full stand is the foundation for high yield. For early sowing and fertile land, sowing may be appropriately sparse.

2. Fertilization: Soybean has root nodules that fix nitrogen, so excessive fertilization is not advisable. A small amount of nitrogen, phosphorus, and potassium compound fertilizer may be applied before sowing at 20-30 kg per mu. During the flowering period, a small amount of urea may be applied as topdressing according to growth conditions.

3. Integrated control: In the south, cutworms severely damage seedlings. Before plowing, 3% carbofuran may be applied at 1.5 kg per mu to control soil-dwelling pests. During the growth period, pay attention to using pesticides to control leaf-feeding pests. Nannong 88-31 has comprehensive resistance to common diseases and generally does not require special disease prevention measures. During the seedling stage, regular intertillage and loosening of the soil should be carried out to prevent soil compaction. Herbicides may be used to control weeds during the seedling stage. Soybean has poor waterlogging tolerance at the seedling stage, and the seedling stage is also the rainy season in the south, so special attention should be paid to matching drainage and irrigation. If heavy rain occurs, drainage should be timely to reduce waterlogging and prevent seedling death. Before row closure, earth up around the roots to loosen the soil, control weeds, and prevent lodging.

4. Late-stage management: Because the plant type is relatively tall, attention should be paid to preventing lodging under conditions of sufficient fertilizer and water. If growth is excessive, paclobutrazol may be sprayed to control height. After maturity in mid October, it should be harvested and threshed in time to prevent seed mildew and rot caused by autumn rain in the south.