A method for mechanized seed production of hybrid rice with simultaneous and staggered sowing of the male parent in the same tray.

Abstract

This invention relates to the field of hybrid rice seed production technology, specifically providing a method for mechanized hybrid rice seed production involving the simultaneous, staggered sowing of male parents in the same seed tray. The method involves sowing the male parents twice in the same seed tray according to a predetermined sowing date difference. Seedling growth is controlled by supplemental blue light or tebuconazole soaking, reducing the competitive advantage of the first-time sown male parent and minimizing the growth difference between the two sown male parents while maintaining leaf age differences. This achieves the goal of mechanized planting of hybrid rice with male parents from two different periods simultaneously without altering the growth cycle. Only one seed tray is needed for transplanting, simplifying the operation process. Conventional rice transplanters can be used for simultaneous, mechanized planting of hybrid rice parents, enabling single-row planting of multiple male parents in one row. This reduces the area occupied by male parents in the seed production field, improves production efficiency, saves labor resources, and is suitable for large-scale operation in large-scale seed production bases, reducing labor costs.

Description

Technical Field

[0001] This invention belongs to the field of hybrid rice seed production technology, specifically relating to a method for mechanized hybrid rice seed production by sowing the male parent in the same tray at different times. Background Technology

[0002] The high price of hybrid rice seeds hinders their widespread adoption, with traditional manual seed production being a key factor contributing to the high costs. Seed production is transitioning from small-scale manual labor to large-scale mechanization. The high labor intensity and low efficiency of manual transplanting are no longer suitable for large-scale operations, making mechanized seed production an inevitable trend. While concentrated planting of the female parent facilitates mechanized transplanting, the male parent requires staggered sowing and intercropping to ensure pollen supply and flowering timing. However, the complex distribution of fields makes precise transplanting with conventional agricultural machinery difficult, becoming a key bottleneck for fully mechanized seed production. New technologies and methods are urgently needed to overcome this predicament and achieve full mechanization of hybrid rice parent transplanting.

[0003] Chinese patent CN201210509166.7 proposes a mechanized seed production technology for hybrid rice. The technology involves mechanical transplanting of the female parent after tray seedling raising, and manual transplanting of the male parent after moist seedling raising. It boasts good adaptability and is not limited by sowing differences or crop rotation. However, it has four shortcomings: First, manual transplanting of the male parent requires a large workforce, restricting seed production efficiency and consistency, which is inconsistent with the trend of full mechanization. Second, the transplanting process for both parents is complex, increasing the difficulty and time cost of field operations. Third, it is not well-suited to existing agricultural machinery, requiring special adjustments or equipment, and its applicability to different varieties is poor, limiting its widespread adoption. Fourth, flowering time control is easily affected by environmental factors, resulting in insufficient stability and potentially impacting seed yield and quality.

[0004] Chinese patent CN202010646864.6 proposes a method for simultaneous transplanting of hybrid rice parent lines in a single machine. By setting row ratios, seedling raising in batches, and simultaneous transplanting, the method uses a conventional rice transplanter to achieve simultaneous transplanting of parent lines, eliminating the need for dividing the seedbeds and clearly distinguishing the parent lines, thus improving transplanting efficiency. However, it has two shortcomings: First, the two parent lines need to occupy a separate row of seedbeds, making it impossible to place them together in a single row of seedbeds. To achieve simultaneous transplanting of parent lines, the process is complex, requiring multiple operations or the customization of special rice transplanters, which fails to fundamentally improve efficiency. Second, missing parent lines may affect population uniformity and pollen supply stability, potentially leading to insufficient pollination in some areas during large-scale seed production, thus affecting seed yield.

[0005] Chinese patent CN202310768181.1 provides a method and apparatus for simultaneous male parent transplanting and female parent sowing and covering in hybrid rice seed production. It integrates ditching, sowing, covering, and transplanting functions, simplifying the steps and improving efficiency and yield. However, it has three shortcomings: First, the equipment structure is complex, and maintenance and replacement after failure are difficult, increasing usage and time costs. Second, it has high requirements for field flatness and soil texture, and the preliminary preparation is cumbersome. It is difficult to adapt to fields with poor terrain or soil conditions, limiting its widespread application. Third, adjusting the parent row ratio is cumbersome, the available combinations are limited, and the planting flexibility is insufficient.

[0006] To address the shortcomings of existing technologies, the field has attempted "same-tray sowing," which involves sowing two generations of male parents in the same seedling tray, aiming to occupy only one seedling box during transplanting. However, due to the lack of effective growth control, this approach has led to a fatal "seedling competition" problem: the first-generation male parent, with its significant advantage in plant height and growth, severely shades and suppresses the second-generation male parent sown later, resulting in a sharp decline in the seedling survival rate and a significant increase in the rate of weak seedlings. Ultimately, due to substandard seedling quality, this approach cannot be applied in practice.

[0007] Therefore, existing technologies lack a core technology that can coordinate the competition between the two parent plants in the same space, both reducing their plant height differences to adapt to machine transplanting and maintaining their leaf age differences to ensure flowering period. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention provides the following technical solution:

[0009] A method for staged sowing of the male parent in the same tray, wherein the method uses blue light supplemental lighting to regulate the growth of the first-stage seedlings, includes the following steps:

[0010] (1) First-stage male parent sowing: First, determine the appropriate sowing period, and then select high-quality seeds for sowing; the sowing ratio of the first-stage male parent to the second-stage male parent is set at 0.8~0.9:1~1.2. The sowing method can be row sowing or broadcast sowing. The total sowing amount is determined according to the variety type and specific sowing method; before sowing, the seeds need to be rinsed to remove the floating and sinking seeds, and then soaked in clean water for 48 hours.

[0011] (2) Pure blue light supplementation: Special rice seedling substrate is selected for seedling raising, and special seedling trays that can be stacked are used. After the first stage of male parent sowing is completed, the seedlings are raised by stacking trays. The trays are stacked in a dark room with a temperature of 30-32℃ and a relative humidity of more than 90% for 48 hours. When the seedling height reaches 0.5cm, the seedlings are placed in a pure blue light environment for continuous irradiation for 7-10 days. The specific blue light irradiation time is determined according to the sowing period of the second stage male parent.

[0012] (3) Second-stage male parent sowing: The specific sowing time of the second-stage male parent is determined based on the pre-set sowing time difference between the two stages of male parents. Before sowing, the seeds are soaked in clean water for 48 hours. Then, the second-stage male parent is sown directly in the seedling tray of the first-stage male parent. After sowing, the seedling is covered with the special rice seedling substrate.

[0013] (4) Transplanting: After the second-stage male parent seedlings emerge, they are transferred to the seedbed and the seedlings are cultivated by machine transplanting and dry seedling raising. During this process, the seedbed must always be kept in a dry field state. Before transplanting, the seedling roots are encouraged to grow strong by controlling water and suppressing seedling growth.

[0014] A method for staggered sowing of the male parent in the same tray, wherein the method uses acetamiprid seed soaking to regulate the growth of the first-stage seedlings, includes the following steps:

[0015] (1) First-stage male parent sowing: First, determine the appropriate sowing period, and then select high-quality seeds for sowing; the sowing ratio of the first-stage male parent to the second-stage male parent is set at 0.8~0.9:1~1.2. The sowing method can be row sowing or broadcast sowing. The total sowing amount is determined according to the variety type and specific sowing method; before sowing, the seeds need to be rinsed to remove floating and sinking seeds, and then soaked in 20ppm acetamiprid for 48 hours; special rice seedling substrate is used for seedling raising, and special seedling trays that can be stacked are used. After the first-stage male parent sowing is completed, the seedlings are all raised by stacking trays. The trays are stacked in a dark room with a temperature of 30-32℃ and a relative humidity of more than 90% for 48 hours; when the seedling height reaches 0.5cm, they are stacked.

[0016] (2) Second-stage male parent sowing: The specific sowing time of the second-stage male parent is determined based on the pre-set sowing time difference between the two stages of male parents. Before sowing, the seeds are soaked in clean water for 48 hours. Then, the second-stage male parent is sown directly in the seedling tray of the first-stage male parent. After sowing, the seedling is covered with the special rice seedling substrate.

[0017] (3) Transplanting: After the second-stage male parent seedlings emerge, they are transferred to the seedbed and the seedlings are cultivated by machine transplanting and dry seedling raising. During this process, the seedbed must always be kept in a dry field state. Before transplanting, the seedling roots are encouraged to grow strong by controlling water and suppressing seedling growth.

[0018] The beneficial effects of this invention are:

[0019] 1. Hybrid rice male parent sowing in the same tray at different times. The male parent is sown twice in the same seedling tray according to the predetermined sowing time difference. Through physical (blue light supplemental lighting) or chemical (uniconazole seed soaking) seedling control measures, the competitive advantage of the first-time sown male parent is reduced, the growth difference between the two male parents is reduced while maintaining the leaf age difference, and the growth period is not changed. This ensures that the quality of male parent seedlings at different times reaches the level of conventional tray-based staggered sowing, significantly reducing the rate of weak seedlings and seedling death, increasing the seedling survival rate, and ultimately achieving the goal of mechanized planting of hybrid rice with male parents at two different times.

[0020] 2. The technique of staggered row sowing or broadcast sowing of hybrid rice male parents in the same tray. These two different sowing methods allow for alternating planting of first- and second-generation male parents during machine transplanting in seed production fields. Row sowing helps to evenly distribute the male parents, thus improving pollination uniformity and success rate. Broadcast sowing allows for planting first- and second-generation male parents in the same hole, ensuring that male parents from different stages meet the female parent at the crucial flowering period. These two sowing methods can simulate the effect of alternating planting of two-stage male parents during manual transplanting without increasing labor costs, thereby improving seed production success rate.

[0021] 3. Enables simultaneous mechanized planting of parent lines. By placing both parent lines on the same rice transplanter, the male line only needs to occupy one seedbed, while the remaining seedbeds hold the female line. This allows for simultaneous, mechanized planting of hybrid rice parents on the same machine, enabling single-row planting of the male line. This reduces the area occupied by the male line in the seed production field while ensuring the presence of two generations of male lines. It is suitable for ordinary rice transplanters, simplifies agricultural operation, effectively improves seed production efficiency, and saves labor and costs. Attached Figure Description

[0022] Figure 1 This is a comparison of plant height and leaf age between the first and second stages.

[0023] Figure 2 This is a flowchart of the operation process.

[0024] Figure 3 This is a schematic diagram illustrating the specific operation.

[0025] Figure 4 Comparison of seedlings treated with different methods.

[0026] Figure 5 Comparison of seedlings treated with different methods. Detailed Implementation

[0027] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected. Example 1

[0028] In 2024, the applicant applied the technical solution described in this invention to test two methods of sowing male parents. The method of sowing male parents seedlings separately in two stages was used as control example 1, and the method of sowing male parents in the same tray in stages without seedling control measures was used as control example 2.

[0029] 1. Tested restorer lines (paternal parent) varieties: Zhehui 1578; Zhonghui 210

[0030] 2. Implementation Plan:

[0031] Example 1: The male parent was sown in two stages with a 7-day difference between the sowing dates. The sowing method of sowing in the same tray in stages was used, and the growth of the first stage male parent was regulated by physical means (blue light supplemental lighting for 7 days).

[0032] The specific steps are as follows:

[0033] (1) First-stage male parent sowing: Determine the appropriate sowing period, and then select high-quality seeds for sowing; The sowing ratio of the first-stage male parent to the second-stage male parent is set at 0.8~0.9:1~1.2. The sowing method is row sowing or broadcast sowing. The total sowing amount is determined according to the variety type and specific sowing method; Before sowing, the seeds are rinsed to remove the floating and sinking seeds, and then soaked in clean water for 48 hours.

[0034] (2) Pure blue light supplementation: Special rice seedling substrate was selected for seedling raising, and special seedling trays that can be stacked were used. After the first male parent was sown, the seedlings were raised by stacking trays. The trays were stacked in a dark room with a temperature of 30-32℃ and a relative humidity of over 90% for 48 hours. When the seedling height reached 0.5cm, the seedlings were placed in a pure blue light environment for 7 days.

[0035] (3) Second-stage male parent sowing: The specific sowing time of the second-stage male parent is determined based on the pre-set sowing time difference between the two stages of male parent. The second-stage male parent is soaked in clean water on the 5th day after the first-stage male parent is sown. After the first-stage male parent is supplemented with blue light for 7 days, the second-stage male parent is sown directly in the seedling tray of the first-stage male parent. After sowing, the special rice seedling substrate is covered.

[0036] (4) Transplanting: After the second-stage male parent seedlings emerge, they are transferred to the seedbed and the seedlings are cultivated by machine transplanting and dry seedling raising. During this process, the seedbed must always be kept in a dry field state. Before transplanting, the seedling roots are encouraged to grow strong by controlling water and suppressing seedling growth.

[0037] Example 2: The male parent was sown in two stages with a 7-day difference between the sowing dates. The sowing method of sowing in the same tray in stages was used, and the growth of the first stage male parent was regulated by chemical means (soaking seeds in 20 ppm of acetamiprid).

[0038] The specific steps are as follows:

[0039] (1) First-stage male parent sowing: First, determine the appropriate sowing period, and then select high-quality seeds for sowing; the sowing ratio of the first-stage male parent to the second-stage male parent is set at 0.8~0.9:1~1.2, and the sowing method is row sowing or broadcast sowing. The total sowing amount is determined according to the variety type and specific sowing method; before sowing, the seeds need to be rinsed to remove floating and sinking seeds, and then soaked in 20ppm acetamiprid for 48 hours; special rice seedling substrate is used for seedling raising, and special seedling trays that can be stacked are used. After the first-stage male parent sowing is completed, the seedlings are all raised by stacking trays. The trays are stacked in a dark room with a temperature of 30-32℃ and a relative humidity of more than 90% for 48 hours; when the seedling height reaches 0.5cm, they are stacked.

[0040] (2) Second-stage male parent sowing: The specific sowing time of the second-stage male parent is determined based on the pre-set sowing time difference between the two stages of male parents. Before sowing, the seeds are soaked in clean water for 48 hours. Then, the second-stage male parent is sown directly in the seedling tray of the first-stage male parent. After sowing, the seedling is covered with the special rice seedling substrate.

[0041] (3) Transplanting: After the second-stage male parent seedlings emerge, they are transferred to the seedbed and the seedlings are cultivated by machine transplanting and dry seedling raising. During this process, the seedbed must always be kept in a dry field state. Before transplanting, the seedling roots are encouraged to grow strong by controlling water and suppressing seedling growth.

[0042] Compare with Example 1:

[0043] The male parent was sown in two separate periods, with a 7-day difference between the sowing dates, using a separate sowing and seedling raising method.

[0044] The specific steps are as follows:

[0045] (1) First-stage male parent sowing: First, determine the appropriate sowing period, and then select high-quality seeds for sowing; the sowing ratio of the first-stage male parent to the second-stage male parent is set at 0.8~0.9:1~1.2. The sowing method can be row sowing or broadcast sowing. The total sowing amount is determined according to the variety type and specific sowing method; before sowing, the seeds need to be rinsed to remove floating and sinking seeds, and then soaked in 20ppm acetamiprid for 48 hours; special rice seedling substrate is used for seedling raising, and special seedling trays that can be stacked are used. After the first-stage male parent sowing is completed, the seedlings are all raised by stacking trays. The trays are stacked in a dark room with a temperature of 30-32℃ and a relative humidity of more than 90% for 48 hours; when the seedling height reaches 0.5cm, they are stacked.

[0046] (2) Second-stage male parent sowing: The specific sowing time of the second-stage male parent is determined based on the pre-set sowing time difference between the two stages of male parents. Before sowing, the seeds are soaked in clean water for 48 hours. Then, the second-stage male parent is sown directly in a seedling tray that is different from the first-stage male parent. After sowing, the seedling is covered with the special rice seedling substrate.

[0047] (3) Transplanting: After the second-stage male parent seedlings emerge, they are transferred to the seedbed and the seedlings are cultivated by machine transplanting and dry seedling raising. During this process, the seedbed must always be kept in a dry field state. Before transplanting, the seedling roots are encouraged to grow strong by controlling water and suppressing seedling growth.

[0048] Compare with Example 2:

[0049] The male parent was sown in two separate periods with a 7-day difference between the sowing dates. The sowing method was carried out using the same tray with separate sowing periods, and no control measures were taken.

[0050] The specific steps are as follows:

[0051] (1) First-stage male parent sowing: First, determine the appropriate sowing period, and then select high-quality seeds for sowing; the sowing ratio of the first-stage male parent to the second-stage male parent is set at 0.8~0.9:1~1.2. The sowing method can be row sowing or broadcast sowing. The total sowing amount is determined according to the variety type and specific sowing method; before sowing, the seeds need to be rinsed to remove floating and sinking seeds; special rice seedling substrate is used for seedling raising, and special seedling trays that can be stacked are used. After the first-stage male parent sowing is completed, the seedlings are all raised by stacking trays. The trays are stacked in a dark room with a temperature of 30-32℃ and a relative humidity of more than 90% for 48 hours; when the seedling height reaches 0.5cm, they are stacked.

[0052] (2) Second-stage male parent sowing: The specific sowing time of the second-stage male parent is determined based on the pre-set sowing time difference between the two stages of male parents. Before sowing, the seeds are soaked in clean water for 48 hours. Then, the second-stage male parent is sown directly in the seedling tray of the first-stage male parent. After sowing, the seedling is covered with the special rice seedling substrate.

[0053] (3) Transplanting: After the second-stage male parent seedlings emerge, they are transferred to the seedbed and the seedlings are cultivated by machine transplanting and dry seedling raising. During this process, the seedbed must always be kept in a dry field state. Before transplanting, the seedling roots are encouraged to grow strong by controlling water and suppressing seedling growth.

[0054] 2. Determination of test results:

[0055] On the 28th day after sowing, seedling height, leaf age, weak seedling rate, seedling mortality rate, and seedling survival rate were measured at fixed points for Examples 1, 2, 1, and 2, with three replicates. Based on these measurements, plant height, leaf age, and difference charts, as well as a seedling quality table, were plotted for the same-tray staggered sowing method described in this invention. Plant height and leaf age difference charts were plotted at 28 days, and seedling quality was investigated.

[0056] Plant height difference = First-stage male parent plant height - Second-stage male parent plant height;

[0057] Leaf age difference = Leaf age of the first-stage paternal parent - Leaf age of the second-stage paternal parent;

[0058] Weak seedling rate = Number of weak seedlings / Total number of seedlings * 100%. Weak seedlings refer to seedlings with a height less than 1 / 2 of normal seedlings, fewer than 1 / 2 of normal seedlings, and thin stems.

[0059] Seedling mortality rate = (Number of dead seedlings / Total number of seedlings) * 100%;

[0060] Seedling survival rate = (Number of seedlings / Total number of seeds sown) * 100%

[0061] The test results are shown in Figure 1 As shown in Table 1:

[0062] Table 1 Seedling Quality

[0063]

[0064] Depend on Figure 1 As shown in 1-3, after using blue light supplemental lighting or tebuconazole soaking to control seedling growth in this experiment, the height of the first-stage male parent plants of both varieties was significantly reduced. For Zhehui 1578, the height was reduced by 12.47%-22.28% and 30.27%-38.09% in Examples 1 and 2, respectively, while for Zhonghui 210, the height was reduced by 33.89%-36.18% and 39.57%-41.71% in Examples 1 and 2, respectively. The second-stage plant height of both varieties was lower than that of the control in the examples, but there was no significant difference. The difference in plant height between the two stages of both varieties was lower than that of the control, indicating that the difference in plant height between the first-stage and second-stage male parents was reduced. In particular, the plant height difference of Zhonghui 210 even reached a negative value, indicating that the plant height of the first-stage and second-stage male parents was the same.

[0065] Depend on Figure 1 As shown in sections 4-6, the leaf age of the two varieties in the first and second phase examples differed from the control example, but the difference was not significant as it did not exceed one leaf age. Similarly, the leaf age difference between the two phase examples of the male parent of the two varieties and the control example was also greater than the previous leaf age, but the difference was not significant.

[0066] As shown in Table 1, the weak seedling rate, seedling mortality rate, and seedling survival rate of Examples 1 and 2 were significantly lower than those of Control Example 2, reaching levels comparable to Control Example 1. For Zhehui 1578, the weak seedling rate and seedling mortality rate of Examples 1 and 2 decreased by 82.38%-85.28% and 61.93%-54.59% respectively compared to Control Example 2, while the seedling survival rate increased by 18.55%-20.49%. For Zhonghui 210, the weak seedling rate and seedling mortality rate decreased by 85.05%-87.01% and 42.49%-60.06% respectively compared to Control Example 2, while the seedling survival rate increased by 23.39%-23.72%.

[0067] In summary, the method described in this invention can enable the quality of male parent seedlings at different stages to reach the quality of seedlings sown in conventional trays at different stages.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for mechanized seed production of hybrid rice, characterized in that: First, after sowing the first-stage male parent, growth regulation measures are applied to inhibit the plant height growth of the first-stage male parent. Then, the second-stage male parent is sown in the same tray. The growth regulation measures are blue light supplemental lighting or seed soaking with acetamiprid. After the second-stage male parent emerges, the seedlings are transferred to the seedbed and the seedlings are cultivated by machine transplanting and dry seedling raising. During this process, the seedbed must always be kept in a dry field state. When the growth regulation measure involves supplemental blue light, the steps for sowing in stages on the same tray are as follows: (1) First-stage male parent sowing: The seeds were rinsed to remove the floating and sinking seeds, and then soaked in clean water for 48 hours; the first-stage male parent was sown in the seedling tray; when the seedling height reached 0.5cm, the seedling tray was placed in the LED pure blue light environment for 7 days. (2) Second-stage male parent sowing: Soak the second-stage male parent seeds in clean water on the 5th day after the first-stage male parent sowing. After the first-stage male parent has been supplemented with blue light for 7 days, sow the second-stage male parent seeds directly in the seedling tray of the first-stage male parent. After sowing, cover with rice seedling substrate. The growth regulation measure, when soaking seeds in tebuconazole, involves the following steps for staggered sowing in the same tray: (1) First-stage male parent sowing: The seeds were rinsed to remove the floating and sinking seeds, and then soaked in 20ppm acetamiprid for 48h; the first-stage male parent was sown in the seedling trays; when the seedling height reached 0.5cm, the seedlings were spread out. (2) Second-stage male parent sowing: Soak the second-stage male parent seeds in clean water on the 5th day after the first-stage male parent sowing. On the 7th day, sow the second-stage male parent seeds directly in the seedling tray of the first-stage male parent. After sowing, cover with rice seedling substrate.

2. The method according to claim 1, characterized in that, The seedling trays are stackable special seedling trays. After the first stage of male parent sowing is completed, seedlings are all grown using the stacked tray method.

3. The method according to claim 1, characterized in that, The sowing ratio of the first-stage male parent to the second-stage male parent is 0.8~0.9:1~1.

2.

4. The method according to claim 1, characterized in that, The sowing method is either row sowing or broadcast sowing.

5. A mechanized planting system for hybrid rice parents, characterized in that: The system involves placing male parent seedlings from two different seedling trays, cultivated using the method described in any one of claims 1-4, into a single seedling box, while female parent seedlings are placed into other seedling boxes; and using a rice transplanter to simultaneously transplant a single row of male parent seedlings and multiple rows of female parent seedlings.

Images