Introduction to the new cotton line ZGK9822

ZGK9822 (formerly named Zhong 221) is a new disease-resistant, insect-resistant cotton line bred by the Cotton Research Institute of the Chinese Academy of Agricultural Sciences. It carries two insect-resistance genes, BT and cpTI. This line has passed the genetically modified organism safety assessment of the Ministry of Agriculture.

I. Characteristics: The growth period is 130 days, belonging to the medium-maturing, slightly early type of variety. The plant is tower-shaped and fairly compact, with a plant height of 82 cm. The leaves are medium in size and dark green. It has strong boll-setting ability, and the stems are thick and resistant to lodging. The bolls are oval, with a boll weight of 5.6 g and a lint percentage of 39%. The boll shell is thin, boll opening is smooth and concentrated, making harvesting easy, and the lint is pure white in color. The fiber length is 30.1 mm and the micronaire value is 4.8; the quality indicators meet the requirements for high-quality cotton. It has strong stress resistance and wide adaptability. It has strong disease resistance and belongs to the type resistant to Fusarium wilt and Verticillium wilt. It is resistant to salinity and alkalinity and fairly tolerant to drought, with good leaf function in the late stage. It is highly resistant to the cotton bollworm, and its insect resistance is stable. It is suitable for trial planting and extension in the Huang-Huai River basin and other suitable areas.

II. Yield performance: In the two-year institute-level variety comparison trial from 1998 to 1999, the average pre-frost lint yield was 102.6 kg per 1/15 hectare (1 mu), an increase of 18.1% over the control Zhongmiansuo 19; in the wheat intercropping regional trial in the Yellow River basin from 2000 to 2001, the average pre-frost lint yield was 85.1 kg per 1/15 hectare, an increase of 12.8% over the control Zhongmiansuo 19; in 2001, it participated in the national transgenic variety production trial, with a pre-frost lint yield of 95.8 kg per 1/15 hectare, an increase of 16.4% over Xinmian 33B and 8.1% over 99B; in 2002, in a demonstration planting at the Jinqiu Seed Industry good-seed propagation base in Xiajin, Shandong (contact phone: 0534-3269172), the lint yield was 124.1 kg per 1/15 hectare.

III. Key cultivation points: (1) Sow at the right time and plant at a reasonable density. For plastic-film-mulched cotton, the suitable sowing period is after Grain Rain (April 20 to 25), and sowing should not be too early. As for planting density, in high-fertility and high-water cotton fields, 3000-5000 plants per 1/15 hectare; in ordinary cotton fields, 3500-4000 plants. (2) Use plant growth regulators flexibly. According to the principle of "watching the sky, watching the soil, and watching the seedlings," with the chemical regulation goal of "healthy cotton plant growth, steadily building a high-yield framework, and setting more bolls," use regulators scientifically and flexibly in split, small doses, and by no means over-regulate, which would affect normal growth. (3) Prevent and control diseases and insect pests. Except in outbreak years, the second generation of cotton bollworm generally does not need control; for the third and fourth generations of cotton bollworm, control as appropriate according to larval density, with the control threshold being 10-15 larvae per 100 plants. Other pests such as cotton aphids, red spider mites, and plant bugs should be controlled in a timely manner; for the control of Fusarium wilt and Verticillium wilt, comprehensive measures of "prevention first, nutritional strengthening of seedlings, and treatment for recovery" should be adopted to keep the damage under control. (4) Prune in a timely manner. This variety grows and develops rapidly in the early stage and has a low node position for squaring, so lower-node pruning is required to be timely and thorough. For early-developing cotton, to prevent premature senescence, early buds can be removed or 1-2 lower fruiting branches can be removed. (5) This variety is relatively sensitive to fertilizer and water, so fertilizer and water management should be strengthened promptly and scientifically.