Detailed Introduction to the Soybean Variety Kangxian 2

Kangxian 2 was developed by the Saline-Alkali Land Crop Breeding Research Institute of the Heilongjiang Academy of Agricultural Sciences in collaboration with the Institute of Plant Protection of the Chinese Academy of Agricultural Sciences. In 1982, a sexual cross was made using Nenfeng 9 as the female parent and (Nenfeng 10 x Frenklin) F2 as the male parent. The progeny were continuously planted and identified in a soybean cyst nematode disease nursery, combined with southern multiplication and generation advancement, and selected and bred using the modified pedigree method, producing a new soybean variety with high resistance to soybean cyst nematode. Original code: Fuyu 8201-205.

Characteristics: This variety has an indeterminate podding habit, a plant height of about 95 cm, and the main stem has 16 to 18 nodes, with 1 to 2 branches, round leaves, white flowers, gray pubescence, and mostly 3-seeded pods. Yellow seed, brown hilum, 100-seed weight about 18 to 20 g. Protein content 38%, oil content 20.54%. Highly resistant to soybean cyst nematode race 3, moderately resistant to race 4. It has relatively strong drought tolerance, waterlogging tolerance, and saline-alkali tolerance. The growth period is about 120 days, with an active accumulated temperature of 2500 degrees C.

From 1991 to 1994, variety regional trials were conducted in Anda, Dumeng, Lindian, Tailai and other places in western Heilongjiang. The average yield over 21 site-times was 130.82 kg per mu, an increase of 42.8% over the control variety Hefeng 25. In the 1993 to 1994 production trials, the average yield over 8 site-times was 155.6 kg per mu, an increase of 44.8% over the control Hefeng 25. Investigations showed that soybean cyst nematode disease occurs widely and rather severely in western Heilongjiang, and adverse natural conditions such as saline-alkali soil and drought further aggravated the degree of damage. Hefeng 25 is not resistant to soybean cyst nematode; with it as the control, Kangxian 2 increased yield at all trial site-times (1% to 138%). At sites with mild disease, the yield increase was slight, and as the disease severity increased, the yield increase amplitude rose. From 1994 to 1995, in western Heilongjiang, Baicheng and Da'an in Jilin, and Ulanhot, Jalaid Banner and Chifeng in Inner Mongolia and other places, production demonstrations were conducted under different previous crops (including continuous and return cropping). The results showed that when Kangxian 2 was planted under continuous and return cropping, its yield was equal to or slightly lower than under normal rotation, with a yield reduction of 2% to 7%. The usual yield is about 150 to 200 kg per mu, with a maximum of 262.5 kg.

Breeders: Saline-Alkali Land Crop Breeding Research Institute of the Heilongjiang Academy of Agricultural Sciences, Institute of Plant Protection of the Chinese Academy of Agricultural Sciences

Regions and techniques: 1. Fine land preparation. Carry out autumn land preparation, deep plowing, deep loosening or ridge cultivation to prepare good soil conditions for timely early sowing and full, strong seedlings. 2. Rational fertilization. Base fertilizer: apply more than 1 t of high-quality barnyard manure to the previous crop or in combination with autumn land preparation. Seed fertilizer: apply 10 to 15 kg of diammonium phosphate and 5 kg of potassium fertilizer per mu, placed 4 to 5 cm below the seed or applied deeply in layers. Never place seed and fertilizer together, so as to avoid missing plants and broken rows caused by chemical fertilizer damage. 3. Timely early sowing: sow in early May in western Heilongjiang, keeping about 15,000 plants per mu; fertile land should be thinner. Kangxian 2 has a well-developed root system and lush plants, so overly dense planting must be avoided. 4. Continuous and return cropping in nematode disease areas (including plots where yield was severely reduced due to nematode damage): strengthen control of major diseases and pests other than nematodes, such as root rot, root maggot, and pod borer. 5. Planting in low-lying saline-alkali land: deep plow (or deep loosen) and form ridges, then sow on the ridges, which can effectively reduce the degree of damage from flooding and saline-alkali conditions.

Adaptation range: Western parts of the three northeastern provinces and adjacent parts of Inner Mongolia are severe soybean cyst nematode disease areas. According to current identification results, the soybean cyst nematode populations in most places belong to race 3, and Kangxian 2 is applicable. In nematode disease areas where the race type has not been clarified, physiological race identification or production demonstration must be carried out before applying this variety.