Introduction to the Bollgard 410B Cotton Variety

Variety source: Bollgard 410B is another new transgenic insect-resistant cotton variety developed by the American companies Monsanto and Delta and Pine Land using modern high-tech biotechnology.

Approval status: In 2001 it received approval from the Ministry of Agriculture for commercial production, and in the same year it passed variety approval in Anhui Province. It is currently one of the key new transgenic insect-resistant cotton varieties promoted in Anhui Province.

Characteristics and traits: Bollgard 410B is a medium-early maturing variety, with a growth period of about 123 days, a plant height of about 105 cm, upward-angled fruiting branches, shorter fruiting nodes, a clean and compact plant type, and very strong boll-setting ability. The single boll weight of mid-canopy bolls is about 5.0 grams, the lint percentage is about 39%, the cotton fiber is white and silky, and the micronaire value is moderate; it has such characteristics as strong insect resistance, early maturity, good yield performance, and excellent fiber quality.

This variety is highly resistant to cotton (pink) bollworm, so it can not only save pesticide expenses and reduce the probability of pesticide poisoning, but also lessen environmental pollution.

Under normal conditions, this variety matures early in the late stage without premature senescence. In cases of bud and boll shedding caused by lack of fertilizer and water, high temperature, or drought, its compensatory ability is strong and its boll-setting speed is fast; as long as the temperature is suitable and management is strengthened, a relatively high yield can still be obtained. This variety has good tolerance to Fusarium wilt and strong recovery ability after infection. It is suitable for planting in Anhui Province.

Bollgard 410B has good yield performance. The average lint yield in provincial regional trials was 100.7 kg per mu, and high-yield plots in demonstration fields reached more than 130 kg. According to sampling surveys at multiple points across the province, under the especially high-temperature and droughty climate of 2001, Bollgard 410B averaged 262.2 kg of seed cotton per mu (equivalent to 97.1 kg of lint). Planting Bollgard 410B yields 200-300 yuan more per mu in benefits than planting other varieties.

Key cultivation points:

(1) Sow at the proper time.

For Bollgard 410B, the sowing period should preferably be from late mid-April to early May. In the Huaibei cotton region, spring cotton and transplanted cotton can be advanced to late mid-April, while wheat-stubble cotton is best sown in early May; in the cotton region along the Yangtze River, transplanted cotton is best planted in late April.

(2) Reasonable close planting. For general fields, about 2,500 plants per mu; for fields with higher fertility or transplanted cotton, 2,000 plants per mu; for fields with lower fertility or hilly and ridge land, more than 3,000 plants per mu; in the cotton region along the Yangtze River, 2,000-2,500 plants per mu; in the Huaibei cotton region, 2,500-3,000 plants per mu.

(3) Potassium fertilizer is indispensable, and boron fertilizer is also needed. This variety is sensitive to potassium. Therefore, potassium fertilizer applied to Bollgard cotton fields must not be less than 20 kg per mu, applied in two split applications as base fertilizer and flowering-boll fertilizer, 10 kg each time, watered on with water. On the premise of applying sufficient potassium fertilizer, boron fertilizer should be applied well. Boron fertilizer is generally applied as base fertilizer at 1 kg per mu; if boron fertilizer was not applied as base fertilizer, a 0.2% borax aqueous solution can be sprayed on the leaves 2-3 times at the bud stage and the full bud to early flowering stage.

(4) Increase fertilizer application and balance fertilization. Generally, apply 10-20% more per mu than for conventional cotton. Apply sufficient base fertilizer, increase organic fertilizer and phosphorus and potassium fertilizers, apply seedling fertilizer lightly, apply flowering-boll fertilizer heavily, and increase topping fertilizer. Balanced fertilization should be carried out according to the fertility level of the cotton field.

For a general cotton field, the base fertilizer per mu includes: 1,000-1,500 kg of farmyard manure, 50 kg of phosphate fertilizer, 10 kg of urea, 10 kg of potassium fertilizer, and 1 kg of boron fertilizer; seedling-stage topdressing should be applied appropriately according to seedling conditions; flowering-boll fertilizer is applied in two split applications, the first at the early flowering stage (appropriately delayed for cotton fields with overly vigorous growth), with 50 kg of cake fertilizer, 10 kg of urea, and 10 kg of potassium fertilizer per mu; the second at the full flowering and boll-setting stage, with 10-15 kg of urea per mu; topping fertilizer can be applied at about 10 kg of urea per mu according to late-stage boll-setting conditions.

(5) Timely and appropriate chemical regulation. When growth is vigorous or there is more rain, chemical regulation should be carried out appropriately. The dosage of mepiquat chloride per mu should be controlled at: 0.5 g at the seedling stage, 1 g at the bud stage, 1.5-2 g at the flowering-boll stage, and 2-3 g after topping.

(6) Cotton fields must not be dry; irrigate with a small amount of water when drought occurs. The flowering-boll stage has a relatively high water requirement and is a water-sensitive period. If drought occurs during the flowering-boll stage, irrigate promptly, using small furrow irrigation, and by no means flood irrigation.

(7) Topping should not be too early, and late-stage management should be done well. Bollgard 410B sets bolls quickly, sets many bolls, and has a relatively high yield level. In order to increase effective buds in the late stage and increase autumn boll setting, topping should not be too early; the topping time should be 5-7 days later than for local conventional varieties.

Late-stage management: First, apply topping fertilizer heavily. After topping, apply 10 kg of urea per mu; the fertilization time is late July in the Huaibei cotton region and early August in the cotton region along the Yangtze River. Second, spray fertilizer on the leaves. The number of foliar fertilizer sprays should be increased by 1-2 times compared with conventional cotton, from mid-August to late September, once every 8-10 days, for 4-5 sprays. The fertilizers sprayed are mainly a 1-2% urea aqueous solution and a 0.2% potassium dihydrogen phosphate aqueous solution.

(8) Pest and disease control. Bollgard 410B is only highly resistant to cotton (pink) bollworm; other cotton pests and diseases still need to be controlled conventionally, with special attention to the control of cotton aphids, thrips, red spider mites, cotton leafworms, and plant bugs. Bollgard 410B is relatively tolerant to Fusarium wilt; lightly diseased fields should use disease-free guest soil or pond mud for seedling raising, and heavily diseased fields should be rotated with rice and other grass-family crops.