Introduction to the Characteristics of the Lu H28 Cotton Variety
1. Breeding and Approval Unit
Lu H28 is an inter-varietal hybrid of upland cotton developed by the Shandong Cotton Research Center using two lines, 92188 and 42-1, as parents. In 1993-1994 it performed outstandingly in the Shandong Province hybrid cotton regional trial, and in 1995 it was approved and named by the Shandong Province Crop Variety Approval Committee.
2. Main Characteristics
(1) Yield Level
In the 1993-1994 Shandong Province hybrid cotton regional trial, the two-year 8-site average pre-frost lint yield was 885 kg/ha, 22.7% higher than the control Zhongmian No. 12, ranking first among the tested varieties. In 1993 the average pre-frost lint yield was 718.50 kg/ha and in 1994 it was 1050 kg/ha, respectively 14.3% and 28.9% higher than the control Zhongmian No. 12. In 1995, in a 0.4 ha field of the Yutai 3-1 style spring wheat-cotton intercropping system, expert measurement and acceptance gave an average yield of @#@245@#@5661 kg/ha, with a lint yield of 2254.5 kg/ha.
(2) Fiber Quality The 2.5% span length is 29.5 mm, the specific strength is 21.0 cN tex-1, and the micronaire value is 3.9.
(3) Disease Resistance The Fusarium wilt index is 6.91, and the Verticillium wilt index is 19.46.
(4) Growth Characteristics
Lu H28 has a whole growth period of 132.2 days and a pre-frost boll opening rate of 85.3%. It is a new medium-maturing hybrid cotton variety. The plant is relatively loose and tower-shaped, with a plant height of 100 cm and 11.8 fruiting branches per plant. The fruiting branches are slightly long, the leaves are medium-sized, and the leaf color is slightly dark. The cotton boll is oval, with a boll weight of 5.8 g, a lint percentage of 38.8%, and a seed index of 10.9 g.
3. Suitable Regions
For single-cropping spring sowing in the Yellow River basin cotton region; for spring wheat-cotton intercropping in the central and southern cotton regions of this basin, high yields can also be obtained by adopting early-promoting measures such as film mulching, seedling raising, and transplanting.
4. Key Points of Cultivation Technology
(1) Scientific Fertilization
The Lu H28 hybrid is tolerant of fertilizer and water and has high yield potential. Generally, apply 45-60 tonnes of high-quality organic fertilizer, 600 kg of cake fertilizer, 300 kg of potassium sulfate, and 15-20 kg each of zinc sulfate and borax per hectare as base fertilizer. Apply a light fertilizer to promote seedling growth, and apply heavy fertilizer at the flowering and boll stage and as a topping fertilizer, so as to give full play to this variety's strong boll-setting characteristics, achieve the setting of all three boll crops, and have autumn bolls cover the top without premature senescence. Combined with insect control, spray plant growth regulators such as 0.3% potassium dihydrogen phosphate, Ainong, Lüfeng 95, and photosynthetic micro-fertilizer.
(2) Reasonable Close Planting
Lu H28 has strong heterosis, with a loose and tall plant shape. The planting density is 30,000-37,500 plants per hectare, with a row spacing of 90-100 cm. Use nutrient-pot seedling transplanting or plastic-film dibbling, with a seeding rate of 7.5-15 kg per hectare.
(3) Full-Process Chemical Regulation
During the cotton growth period, according to the weather and the growth vigor of the cotton plants, flexibly apply mepiquat chloride 3-4 times, following the principle of light application early and heavy application later.
(4) Scientific Insect Control
Do a good job of forecasting, grasp the control period and control thresholds, scientifically select pesticides, alternate and rotate pesticides, improve control quality, and promote new technologies such as stem dripping, stem smearing, spraying, concealed pesticide application methods, and motorized misting and ultra-low-volume equipment, so as to reduce pollution, protect natural enemies, and delay the development of cotton bollworm resistance.
(5) Master Seed Production Technology and Ensure Seed Quality
1) Select cotton fields with flat terrain, fertile soil, good drainage and irrigation conditions, and far from villages and forests for seed production.
2) The Lu H28 hybrid can obtain the same yield increase effect from both direct and reciprocal crosses. When producing seed by direct or reciprocal cross alone, the planting ratio of male and female parents is 1:(5-6); when producing seed by direct and reciprocal crosses at the same time, the planting ratio of male and female parents is 1:1, or the male and female parents are planted in concentrated blocks. The planting method is best with wide and narrow rows, and the density is preferably 30,000 plants per hectare.
3) Seed production time. In the Yellow River basin, all flowers that open from July 5 to August 20 are emasculated and pollinated, and all flower buds before and after are removed, carrying out whole-plant seed production. Each hectare requires 45 seed production workers.
4) Emasculation and pollination. Emasculation is carried out from 2 to 7 p.m., selecting flower buds whose corolla has emerged from the bracts and can open the next morning. The best pollination time is from 8 to 10 a.m. on the second day after emasculation, and it should be finished before 12 noon.
5) Timely harvest. To ensure the boll-setting rate and normal development and maturity of hybrid bolls, pay attention to preventing and controlling damage from diseases and insects, strengthen all field management measures, do a good job of pruning and remove the side tips of fruiting branches during hybridization, and reduce hybrid boll shedding and mechanical damage. At the boll opening and harvest stage, harvest the female parent rows first, then the male parent rows. Harvest, sun-dry, gin, and store separately to ensure purity.