A cultivation method for regulating the expression of key genes related to the development of cotton leafy branches and inhibiting their growth

Abstract

The present invention belongs to the field of crop cultivation, and particularly relates to a cultivation method for regulating the expression of key genes for cotton leafy shoot development and inhibiting their growth. The present invention regulates the expression of key genes for cotton leafy shoot development and inhibits the growth of leafy shoots through double-planting per hole and bundling; one is to sow two seeds per hole during sowing, and do not thin or fix the seedlings after emergence to achieve two plants per hole; the second is to bundle the two cotton plants in the same hole together (the bundling position is the middle and lower parts of the cotton plant) after budding, and at the same time spray the plant growth regulator mepiquat chloride; the third is to perform a second bundling during the early flowering stage (the bundling position is the upper part of the cotton plant), and spray the chemical regulator (mepiquat chloride) again. Compared with the traditional single-plant planting per hole, this method can not only regulate the expression of key genes for leafy shoot development, effectively inhibit the growth of leafy shoots, eliminate the manual leafy shoot removal link, but also enhance the lodging resistance of cotton and reduce rotten bolls.

Description

Technical Field

[0001] The present invention belongs to the field of crop cultivation, and particularly relates to a cultivation method for regulating the expression of key genes for cotton leafy shoot development and inhibiting their growth. Background Art

[0002] Cotton has an indeterminate growth habit and complex branching. It has both monopodial leafy shoots and sympodial fruiting branches, and has a strong apical growth dominance. Cotton leafy shoots are monopodial and are borne at the base of the cotton plant and cannot directly set bolls. Developed leafy shoots will consume the nutrients of the cotton plant, cause shading in the field, affect ventilation and light transmission, and lead to an increase in rotten bolls. Therefore, in cotton field management, leafy shoots are usually removed manually to reduce the adverse effects of leafy shoots.

[0003] Manual pruning is to remove leafy shoots after cotton budding to increase the ventilation conditions at the lower part of the cotton plant and promote the growth and boll setting of fruiting branches. However, with the accelerating development of urbanization, there is a shortage of rural labor, and this traditional cultivation management measure of manual pruning currently faces great challenges. Although increasing the density can effectively inhibit the growth of leafy shoots, as the density increases, the plant spacing decreases, the shading degree between plants deepens, and the competition for light between fruiting branches also intensifies. Compared with the low-density planting mode, the accumulation of dry matter weight of fruiting branches is inhibited under the high-density planting mode, the abscission of buds and bolls and the increase of rotten bolls occur, and the number of bolls set by fruiting branches decreases. Simplified cultivation is the only way for the development of cotton production technology. In view of this, it is very necessary to develop a cultivation method that can inhibit the growth of cotton leafy shoots while not affecting or even promoting the growth and boll setting of fruiting branches, and thus eliminate the manual pruning link. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a cultivation method for regulating the expression of key genes for cotton leafy shoot development and inhibiting their growth.

[0005] The technical solution adopted by the present invention to achieve the above object is as follows:

[0006] The present invention provides a cultivation method for regulating the expression of key genes for cotton leafy shoot development and inhibiting their growth, including the following steps:

[0007] (1) Select high-quality delinted and coated cotton seeds, drill them in holes according to the predetermined hole spacing and row spacing, cover the soil and then cover with plastic film, and do not carry out manual thinning and seedling fixing after emergence;

[0008] (2) After cotton budding, tie two cotton plants in the same hole together once, and then carry out chemical control;

[0009] (3) After cotton flowering, tie two cotton plants in the same hole together for the second time, and carry out chemical control at the same time;

[0010] (4) Carry out conventional field management.

[0011] Further, in step (1), the hole spacing is 25 cm, the row spacing is 76 cm, and the actual harvested density is about 6,000 plants per mu; the number of cotton seeds sown per hole is 2.

[0012] Further, in step (2), the position of the first bundling is above the initial node of the fruiting branches of two cotton plants in the same hole.

[0013] Further, in step (2), the chemical control is to spray mepiquat chloride, and the dosage is 1.5 - 2.0 grams per mu.

[0014] Further, in step (3), the position of the second bundling is at the fourth leaf from the top of the main stem of two cotton plants in the same hole.

[0015] Further, in step (3), the chemical control is to spray mepiquat chloride, and the dosage is 3.0 - 4.0 grams per mu.

[0016] The present invention regulates the expression of key genes for the development of cotton vegetative branches and inhibits the growth of vegetative branches through planting two plants per hole and bundling. First, two seeds are sown per hole during sowing, and no thinning or seedling fixing is carried out after emergence, so as to achieve two plants per hole. Second, after budding, the two cotton plants in the same hole are bundled together (the bundling position is in the middle and lower parts of the cotton plants), and at the same time, the plant growth regulator mepiquat chloride is sprayed. Third, a second bundling is carried out at the early flowering stage (the bundling position is in the upper part of the cotton plants), and the chemical regulator (mepiquat chloride) is sprayed again. Compared with the traditional planting method of one plant per hole, this method can not only regulate the expression of key genes for the development of vegetative branches, effectively inhibit the growth of vegetative branches, and eliminate the manual removal of vegetative branches, but also enhance the lodging resistance of cotton and reduce rotten bolls.

[0017] The method for inhibiting the growth of vegetative branches by planting two plants per hole of the present invention and its application method have the following advantages compared with the traditional method:

[0018] (1) There is no seedling shortage, and thinning and seedling fixing are avoided. Two seeds are sown per hole, which reduces the probability of missing seedlings caused by single-seed precision sowing compared with sowing one seed per hole; compared with multi-seed hole sowing, the thinning and seedling fixing links are eliminated, saving labor.

[0019] (2) Regulate the expression of key genes for the development of vegetative branches and inhibit the growth of vegetative branches. Under the condition of the same density, planting two plants per hole in the present invention inhibits the growth of vegetative branches, reduces the impact on the growth and boll setting of fruiting branches, and utilizes the self-compensatory mechanism of cotton to promote the growth and boll setting of fruiting branches. Compared with cotton with one plant per hole, the dry weight of the fruiting branches of cotton with two plants per hole increases by 26%, while the dry weight of the vegetative branches decreases by more than 73%.

[0020] (3) Reduce rotten bolls and improve the overall fiber quality of cotton. Compared with the bolls on fruiting branches, the average boll weight of the bolls on vegetative branches is lower and the fiber quality is poorer. After adopting the method of the present invention, the dry matter accumulation amount and the number of vegetative branches of cotton are significantly reduced, and all the bolls on the cotton plant are bolls on fruiting branches, effectively improving the overall fiber quality of cotton. The rotten bolls are reduced by 20-30%, correspondingly reducing the loss of cotton fiber quality;

[0021] (4) Improve lodging resistance. Research shows that planting two plants per hole and tying them together can ultimately significantly improve the lodging resistance of cotton by controlling the population structure, photosynthetic rate of cotton plants, stem structure, and dry matter accumulation and transportation. Description of the Drawings

[0022] Figure 1 Schematic diagram of the cultivation method for suppressing vegetative branches provided by the present invention;

[0023] Figure 2 Differences in the expression of vegetative branch apex-related genes between one plant per hole and two plants per hole in cotton at different growth stages, including photosynthesis-related genes GhLHCB (a) and GhPHY1 (b) ， Auxin response-related genes GhGH3.17 (c) and GhSAUR50 (d), key genes in the brassinolide signal transduction pathway GhBKI1 (e) and nitrogen transport-related genes GhNRT2.7 (f);

[0024] Figure 3 Schematic diagram of cultivation with different tying methods. Specific Embodiments

[0025] The technical solutions of the present invention will be further explained and illustrated below through specific embodiments.

[0026] Example 1

[0027] (1) Select high-quality delinted and coated cotton seeds, and drill 2 seeds per hole according to the predetermined hole spacing and row spacing. In the cotton-growing area of the Yellow River Basin, the hole spacing is 25 cm and the row spacing is 76 cm, and the theoretical density is about 7,000 plants per mu (6,000 plants per mu are actually harvested). The hole spacing and density in other cotton-growing areas are appropriately adjusted according to local ecological conditions. After covering the soil, cover with plastic film, and do not perform artificial thinning and seedling thinning after emergence.

[0028] (2) After cotton buds appear (early June), tie the two plants in the same hole with horticultural twine above the first node of the fruiting branch, and then spray mepiquat chloride for chemical control, and the dosage used is 1.5 times the conventional dosage (2.0 grams per mu).

[0029] After the cotton plants bloom (in early June 7th), the two cotton plants in the same hole are tied up for the second time at the fourth leaf from the top of the main stem, and at the same time, mepiquat chloride is sprayed for chemical control, and the dosage used is twice the conventional dosage (4.0 g / mu).

[0030] Effect implementation example

[0031] (1) Conducted at the Linqing Experimental Station of Shandong Cotton Research Center. Cotton variety K836 was selected as the experimental material. The experimental setting plan was as follows: single-plant conventional planting was used as the control, double-plant treatment in one hole was used, repeated 3 times, with a total of 6 plots. 6-row equal-spacing planting was adopted, with a row spacing of 76 cm, and the actual harvested density was controlled at 5,500 - 6,000 plants / mu (such as Figure 1 ). Sowing was carried out on April 20th, and wide film (120 cm) was used to cover two rows in one film. No topping or pruning treatment was done in each plot, and other management measures were the same as those in conventional fields. At the budding stage and the early flowering stage, the double-plant cotton in one hole was tied together manually, and mepiquat chloride was sprayed in due time and appropriate amount each time to control the plant height. The number of leafy branches and plant height of cotton in each plot were investigated at each growth stage. 6 cotton plants were randomly selected and dried to measure the dry weight of leaf branches and fruit branches. After entering the boll stage, the number of cotton bolls in each plot was investigated, and the bolls on leafy branches and fruiting branches were investigated and counted separately.

[0032] The experimental results showed that the method provided by the present invention could effectively control the accumulation of dry weight of leaf branches. Compared with the cotton with one plant per hole, the number of leafy branches of cotton with two plants per hole and the ratio of the dry weight of leaf branches to the total dry matter weight decreased by 57.3% and 72.1% respectively (Table 1). Compared with the leafy branch top of one plant per hole, 9 SAUR genes related to auxin response in the leafy branch top of two plants per hole were all significantly down-regulated in expression, and the expression levels of 3 key genes involved in the brassinolide signal transduction pathway were significantly down-regulated in expression ( Figure 2 ). It shows that this method significantly inhibits the growth of leafy branches and eliminates the manual pruning link by regulating the optimal expression of key genes for leafy branch development.

[0033] Table 1 Comparison of leafy branch characteristics, yield and yield characteristics of cotton with two plants per hole

[0034]

[0035] Note: Different letters after the data in the same column in the table indicate significant differences at the p = 0.05 level.

[0036] (2) Conducted in the cotton field experimental plot in Xinshengdian Town, Xiajin County, Shandong Province. The cotton variety was K836. Single-plant conventional planting was used as the control, double-plant treatment in one hole was used, repeated 3 times, with a total of 6 plots. 6-row equal-spacing planting was adopted, with a row spacing of 76 cm, and the density was controlled at 5,500 - 6,000 plants / mu (such as Figure 1Sowing was carried out on April 23. Wide-film (120 cm) covering with two rows per film was used. No topping or pruning was done in each plot, and other management measures were the same as those in conventional fields. At the budding stage and the early flowering stage, the two cotton plants per hole were manually tied together, and mepiquat chloride was sprayed in due amount each time to control the plant height. The number of vegetative branches and the plant height of cotton in each plot were investigated at each growth stage. Six cotton plants were randomly selected, dried, and the dry weights of vegetative branches and fruiting branches were measured. During the test period, there was a strong wind and rainfall in late July. The lodging rate was counted 2 days after the rain, and the lodged cotton plants were not righted. After the cotton entered the boll stage in early August, the rotten bolls of cotton in each plot were counted, and the yield was counted after the cotton was harvested. The results are shown in Table 2.

[0037] The test results show that the method provided by the present invention effectively inhibits the development of vegetative branches, reduces the rotten boll rate, and increases the seed cotton yield (Table 2). Compared with the cotton with one plant per hole, the number of vegetative branches of the cotton with two plants per hole is reduced by 58.1%, the rotten boll rate is reduced by 71.0%, and the final seed cotton yield is increased by 13.5%. In addition, tying two plants per hole significantly improves the lodging resistance of cotton. Compared with one plant per hole, the lodging resistance of the tied cotton with two plants per hole is increased by 30%.

[0038] Table 2 Effects of two plants per hole on lodging resistance, rotten boll rate and yield of cotton

[0039]

[0040] Note: Different letters under the same factor in the table indicate significant differences at the p = 0.05 level.

[0041] (3) Conducted at the Linqing Experimental Station of Shandong Cotton Research Center. Cotton variety K836 was selected as the test material. The test setting scheme was as follows: two plants per hole without tying; two plants per hole tied only once at the budding stage (tied above the initial node of fruiting branches); two plants per hole tied only once after flowering (tied at the fourth leaf from the top of the main stem); two plants per hole tied twice. Each treatment was repeated 3 times, with a total of 12 plots. The plots were planted in 6 rows with equal row spacing of 76 cm, and the actual harvest density was 5,500 - 6,000 plants per mu (such as Figure 3 ). Sowing was carried out on April 20. Wide-film (120 cm) covering with two rows per film was used. No topping or pruning was done in each plot, and other management measures were the same as those in conventional fields. According to the test settings, the two cotton plants per hole were manually tied at the budding stage and the early flowering stage respectively, and mepiquat chloride was sprayed in due amount each time to control the plant height. The number of vegetative branches and the plant height of cotton in each plot were investigated at each growth stage. Six cotton plants were randomly selected, dried, and the dry weights of vegetative branches and fruiting branches were measured. The number of bolls and rotten bolls of cotton in each plot were investigated during the flower-boll stage, and the yield was investigated at the boll-opening stage.

[0042] The test results show that the bundling method provided by the present invention effectively inhibits the development of cotton leafy branches, reduces the rate of rotten bolls, improves the cotton yield composition, and enhances the yield quality. Compared with no bundling for 2 plants per hole, the number of leafy branches of cotton with only one bundling is reduced by 25% - 33.3%, and the rate of rotten bolls is reduced by 40.1 - 41.0%. While the number of leafy branches with two bundlings is reduced by 69.4%, and the rate of rotten bolls is reduced by 82%. Finally, the seed cotton yield increases with both one and two bundlings. Moreover, bundling twice for 2 plants per hole significantly increases the boll weight, promotes boll setting on fruiting branches, improves the yield composition, and enhances the yield quality.

[0043] Table 3 Effects of different bundling methods per plant on the growth of cotton leafy branches, the rate of rotten bolls and the yield

[0044]

Claims

1. A cultivation method for regulating the expression of key genes for cotton leafy shoot development and inhibiting its growth, characterized in that, It includes the following steps: (1) Select high-quality delinted and coated cotton seeds, sow them in holes according to the predetermined hole spacing and row spacing, cover the soil with plastic film after sowing, and do not carry out manual thinning and seedling fixing after emergence; The number of cotton seeds sown in each hole is 2; (2) After the cotton buds appear, tie up the two cotton plants in the same hole once, and then carry out chemical control; The position of the first tying is above the first node of the fruiting branches of the two cotton plants in the same hole; The chemical control is to spray mepiquat chloride, and the dosage is 1.5 - 2.0 grams per mu; (3) After the cotton blossoms, tie up the two cotton plants in the same hole for the second time, and carry out chemical control at the same time; The position of the second tying is at the fourth leaf from the bottom of the main stem of the two cotton plants in the same hole; The chemical control is to spray mepiquat chloride, and the dosage is 3.0 - 4.0 grams per mu (4) Just carry out conventional field management.

2. The cultivation method according to claim 1, characterized in that, In step (1), the hole spacing is 25 cm, the row spacing is 76 cm, and the actual harvest density is about 6000 plants per mu.

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