GB/T 3242-2026Technical code of practice for the production of cotton basic seed (English PDF)

6.1 Selection of individual plants

6.1.1 Materials selected for individual plant Individual plant selection can be carried out in the field, in the final selection nursery, or a special selection nursery can be set up.

6.1.2 Examination of characteristics Including key characteristics such as plant shape, leaf shape, bell shape, growth period, and stress resistance, as well as boll-setting ability, high yield, disease resistance, insect resistance, and fiber content. Its quality and other traits are consistent with those of the original species.

6.1.3 Timing of Single Plant Selection The first observation is during the peak boll-forming period, observing the morphological characteristics such as leaf shape, plant shape, and boll shape, and marking them accordingly; the second observation is after the bolls open and before the flowers close. Observe the boll formation and fluffing, and remove any atypical individual plants.

6.1.4 Number of individual plants selected The number of individual plants selected should be determined based on the planned area of the nursery for the following year. Select 80 to 100 individual plants per 666.7 m^2 of nursery. It is advisable to select at least.200 individual plants per 666.7m2 row.

6.1.5 Harvesting flowers from a single plant Select individual plants, harvest flowers from one plant, one bag per plant. Harvest at least 5 normally opening bolls (8 for Sea Island cotton) from the lower middle part of each plant, then dry and store. For indoor seed testing. Cotton seeds harvested after frost are not used for seed.

6.1.6 Indoor Selection of Single Plants The evaluation of single-plant materials includes five items. single boll weight, lint percentage, seed index, percentage of seeds with different shapes and colors, and fiber quality (including fiber content). Half-length average, breaking strength, micronaire value, fiber uniformity, and elongation. The ginning percentage of the cotton harvested from a single plant is calculated after ginning; after ginning... Randomly select 100 cottonseeds (excluding insect-infested and broken seeds) and determine the seed index and the rate of off-type and off-color seeds. The rate of off-type and off-color seeds should not exceed 2%. Individual plants meeting all the varietal characteristics criteria are selected for final selection, with a selection rate of 50% being ideal. Fiber quality testing methods shall conform to GB/T 20392. implement.

6.2.1 Field Design and Management

6.2.1.1 Field Design The selected individual seedlings from the previous year are planted in rows in the nursery. Rows are 5-10 meters long, arranged sequentially, with a seedling density 5% lower than in the field. Ideally, one row of the original variety should be placed as a control every nine rows. The row length and number of rows in each section should be consistent, and observation channels should be left between sections. Plant 4 to 6 rows of the original seed of this variety around the perimeter as a protective row, at a height of 1.0m to 1.2m. Design a field planting plan before sowing and sow according to the plan.

6.2.1.2 Field Management Chemical regulation of cotton plants and rows should be light. Other aspects are the same as in field production.

6.2.2 Field observation and identification

6.2.2.1 Record Book Prepare two field observation record books, one original and one copy. The copy should be taken to the field for recording, while the original should be kept indoors. Each observation record should be kept afterward. The original should be copied promptly, or a backup should be made through photocopying, scanning, or photography to establish a system archive. The recorded content should be entered into calculations in a timely manner. Machine, establish database.

6.2.2.2 Observation and Recording Time and Content The survey recorded the dates of seedling emergence, budding, flowering, and boll opening, and observed and recorded the following items.

---Observe uniformity, growth vigor, disease resistance, and insect resistance during the seedling and budding stages; seedlings with a shortage of more than 20% will be initially culled.

---During the flowering and boll-forming stage, observe the typicality, uniformity, disease resistance, insect resistance, and lodging resistance of each row; rows with poor or moderate lodging resistance should be... disuse;

---During the boll-opening stage, its high yield and early maturity can be assessed based on its growth vigor, boll-setting ability, and the degree of concentrated boll opening.

6.2.2.3 Field purity assessment The field purity assessment was conducted in two stages.

---The first examination of plant shape and leaf shape was conducted during the peak budding stage;

---The second observation is during the flowering and bell-forming period, examining plant shape, bell shape, leaf shape, stem color, pubescence, glands, anther color, etc., especially the bell shape.

6.2.2.4 Field Selection Selection or elimination is based on field observation and purity assessment.

---If there is one hybrid plant (mutant or non-variety plant) in a row, the entire row should be eliminated;

---The morphological characteristics conform to the typical characteristics of the original variety, but the seedling emergence, boll setting, early maturity, and stress resistance are significantly different from those of the adjacent control. It should be phased out;

---The selected plants in the field are harvested and their yield is calculated, and then they are selected for final evaluation in the indoor environment.

6.2.3 Indoor variety selection process

6.2.3.1 Selected rows and control rows were observed in the field. For each row, 30 inner bolls were harvested from the 1st to 2nd nodes of the middle fruit branches, after the bolls had fully opened, as samples for evaluation. Samples were analyzed, including single-boll cotton weight, lint percentage, seed index, off-type and off-color seed percentage, average upper fiber length, breaking strength, micronaire value, and fiber content. Uniformity and elongation. Fiber quality testing shall be performed in accordance with GB/T 20392.

6.2.3.2 The selection criteria for each variety are. single boll weight, lint percentage, seed finger and average length of the upper half of the fiber, breaking strength, micronaire value, The fiber uniformity and elongation ratio are no less than 97% of the original variety, and the rate of off-type and off-color seeds is no more than 3%.

6.2.3.3 The final election rate for Zhuxing should be 60%.

6.2.4 Flower collection and ginning in row nurseries The selected rows of cotton seeds harvested before and after frost were collected separately, their yields were calculated, and the seeds were ginned. The seeds from the cottonseed harvested after frost were not used for seed. The eliminated plants... Cotton that has fallen into the ground or is otherwise unprocessed is treated as miscellaneous cotton and is not included in the yield.

6.3 Strain Nursery

6.3.1 Sowing The selected plants from the previous year were planted separately into a lineage nursery and a lineage identification nursery. The planting area for each lineage in the lineage nursery was determined based on the seed... The density should be slightly lower than in the field, depending on the quantity; for the strain identification nursery, there should be 2 to 4 rows, with a row length of not less than 10m and a number of plants of not less than 150, arranged by inter-row comparison. (A control area is set up every four strains, with the original strain of this variety as the control). Field observation, sampling, yield measurement, and variety evaluation are all carried out in the strain identification nursery. Conduct the study and combine it with observation of the strain nursery.

6.3.2 Field investigation and identification Same as 6.2.2.

6.3.3 Field Selection The final selection is based on a comprehensive evaluation of records, yield measurements, and variety testing data.

---When the hybrid rate is >=0.5%, the entire line should be eliminated;

---When the percentage of hybrid plants is less than 0.5%, and other traits meet the requirements, the plants can be selected after removing the hybrid plants;

---During the cotton plant growth period, strains with poor or average lodging resistance should be directly eliminated.

6.3.4 Indoor testing and final selection of strains in the nursery

6.3.4.1 Selected plant lines and control rows in the field, and harvest 50 inner bolls from the first to second nodes of the middle fruit branches of each plant line as test samples. Examine the samples and determine the single boll weight, lint percentage, seed index, off-type and off-color seed rate, average upper half fiber length, breaking strength, micronaire value, and fiber content. Neatness and elongation. Fiber quality testing shall be performed in accordance with GB/T 20392.

6.3.4.2 The selection criteria for the strain are. single boll weight, lint percentage, seed finger and average length of the upper half of the fiber, breaking strength, and micronaire value. Same as the original variety, fiber uniformity is greater than or equal to 85%, and the rate of irregular and discolored seeds is no more than 3%.

6.3.4.3 The final selection rate of strains should ideally be 80%.

6.3.5 Harvesting and ginning cotton from the strain nursery The selected lines were harvested separately for pre-frost and post-frost cotton seeds, their yields were calculated, and the seeds were ginned. Post-frost cotton seeds were not used for seed. The eliminated lines... Cotton that has fallen into the soil or is not included in the yield calculation is treated as miscellaneous cotton.

6.4 Seed Nursery

6.4.1 Sowing, Observation, and Removal of Impurities Seeds from selected strains are mixed and planted to form a seed nursery. The planting density is 5% lower than that for field production, and seedlings can be transplanted or sown in individual holes. Three observations and assessments were conducted during the budding, boll-forming, and fluff-opening stages to investigate the purity of the plants in the field and remove any unwanted plants.

6.4.2 Indoor Examination Methods Based on the plant growth, random sampling was conducted in designated areas. For each sample, 100 normally opening bolls from the middle section were harvested, resulting in a total of 4-5 samples. The samples were examined, and the evaluation items included single boll weight, lint percentage, seed index, percentage of irregularly shaped and colored seeds, average length of the upper half of the fiber, and breaking strength. The micronaire value, fiber uniformity, and elongation were averaged, and then variation and significance analysis were performed.

6.4.3 Harvesting and ginning cotton from the seed nursery Cottonseeds grown before frost are used as primary seeds. Cottonseeds grown after frost and those that have fallen to the ground are treated as mixed cotton and are not counted in the yield calculation.

7.Two-field production The original seed is produced by selecting individual plants, identifying plant rows, and propagating mixed lines. The plant row nursery and the original seed nursery are the same as in Chapter 6.

8.1.1 Establishment of inbred lines

8.1.1.1 Source of Materials Individual plants whose main traits, such as plant shape, bell shape, and leaf shape, conform to the characteristics of the original variety are selected from the breeder's seed field, and high-yield plants are comprehensively evaluated. Sex, fiber quality, disease resistance, insect resistance, etc. The first selection of individual plants is during the budding stage, where morphological characteristics are observed and selected plants are marked; the second selection is during the boll-forming stage, where boll-forming is observed. In addition, a single plant was selected and labeled with a number.

8.1.1.2 Self-fertilization time and quantity During the peak flowering period of cotton, starting when the second fruiting branch of the selected single plant (as described in 8.1.1.1) begins to flower, the flowers on the first to third nodes of all fruiting branches on the entire plant are self-pollinated. Submit and mark the dates; no later than the end of July in the Northwest inland cotton-growing areas, no later than the beginning of August in the Yellow River basin cotton-growing areas, and no later than [date missing] in the Yangtze River basin cotton-growing areas. In late August, self-pollinating bolls are harvested from individual plants according to their assigned numbers. Each plant should yield at least five normally opening self-pollinating bolls. The plant number and boll count are recorded in the bag. Indoor testing was conducted, and.200 individual plants were selected for future use.

8.1.2 Identification of inbred lines

8.1.2.1 Field Design The self-pollinated seeds of the single plants selected in the previous year's final selection were planted in rows according to their numbering order to form inbred lines, with no fewer than 25 plants per line. The same variety of original plants were planted around them. Crop protection area.

8.1.2.2 Field observation and identification Same as 6.2.2.

8.1.2.3 Selection and Self-fertilization During the initial flowering stage, select inbred lines that conform to the varietal characteristics, have uniform morphology, and are growing normally, and mark them. When the second fruiting branch flowers, open... Beginning with self-pollination primarily using flowers at the first fruit node, self-pollination should commence no later than late ...