Breeding method for multi-cropping soybeans in two-wide area

Abstract

The invention discloses a method for breeding multi-cropping soybeans in two-wide areas. The method comprises the following steps: picking pods in a soybean R6 (a full grain filling period), drying at 40 DEG C for 3 days, and peeling grains; setting up a greenhouse for heat preservation when the air temperature is low, and accelerating germination of the seeds in a 30-DEG C germination box for 2 days before low-temperature sowing; the spring soybeans are sown and harvested in four seasons from the first ten days of October to the last ten days of September in the next year, and the summer soybeans are sown and harvested in three seasons from the first ten days of July to the last ten days of June in the next year. Four maturity of spring soybeans in a year and three maturity of summer soybeans in a year in the two-wide area can be achieved without south breeding, the breeding efficiency of the spring soybeans is improved by 100% compared with conventional two-maturity breeding efficiency and is improved by 33.33% compared with existing three-maturity breeding efficiency, the breeding efficiency of the summer soybeans is improved by 200% compared with conventional one-maturity breeding efficiency, cost is remarkably reduced, and the efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of agricultural planting technology and relates to a method for breeding soybeans that can be harvested multiple times a year in the Guangdong and Guangxi regions. Background Technology

[0002] Soybeans are an important grain, oilseed, and feed crop in my country, playing an irreplaceable role in the national economy and people's livelihood. As a major soybean consumer, my country's annual consumption exceeds 100 million tons. The fundamental way to increase my country's soybean production capacity lies in improving yield per unit area, and the most effective method at present is to accelerate the breeding process of new varieties.

[0003] Soybeans are a typical self-pollinating crop, and the main varieties used in production are all self-pollinating. After sexual hybridization, self-pollination typically requires about seven generations. In most parts of northern China with insufficient light and temperature, conventional breeding methods require at least seven years to cultivate stable lines. Even with the help of the Hainan breeding program to achieve two harvests a year, cultivating stable lines often takes more than four years, which severely restricts the progress of soybean research and breeding.

[0004] To accelerate soybean breeding, researchers have conducted a series of studies on multi-cropping technologies per year. Xue Yongguo et al. invented a localized, dwarfing, and rapid generation method for soybeans (patent application number 202010117439.8), achieving rapid generation 4-5 times in a local soybean population by controlling light and temperature in a container combined with chemical control technology. Zhang Caiying et al. developed a local multi-generation soybean breeding method (patent application number 201310075688) that shortens the soybean growth period to an average of 75 days through tissue culture after pod drying, also achieving 4-5 generations per year. Furthermore, Fang Yudong et al. achieved rapid breeding technology for four crops per year through fresh pod sowing and off-site propagation; Jahne et al. used greenhouse LED light source control to shorten the soybean growth period, achieving multi-cropping per year.

[0005] However, most of these existing technologies require a combination of light regulation, temperature control, and off-site breeding, which is costly and difficult for research institutions with limited financial resources to widely apply. Although low-latitude regions such as Guangxi Zhuang Autonomous Region have abundant light and heat resources and long frost-free periods, providing excellent natural conditions for soybean multi-cropping technology, currently, spring soybeans in this region are mostly harvested twice a year, and summer soybeans are mostly harvested once a year. Even with the help of breeding in Hainan, spring soybeans can only achieve three harvests a year, and summer soybeans two harvests a year. Guo Xiaohong et al. have achieved three harvests a year for soybeans in the Huang-Huai-Hai region in Nanning through methods such as fresh pod sowing, but the growth period of local spring soybeans is generally longer than that of soybeans in the Huang-Huai-Hai region, which limits further improvement in breeding efficiency.

[0006] Therefore, given the unique light and heat conditions in the Guangdong and Guangxi regions and the shortcomings of existing technologies, developing a low-cost, easy-to-operate technology that can further increase the number of breeding generations is of great significance for accelerating the soybean breeding process and improving my country's soybean self-sufficiency. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for breeding soybeans in the Guangdong and Guangxi regions that enables multiple harvests per year. This method can achieve four harvests of spring soybeans and three harvests of summer soybeans per year without relying on breeding in Hainan. Compared with conventional breeding methods, this method is more than 100% more efficient and greatly improves the soybean breeding rate.

[0008] This invention provides a method for breeding soybeans that can mature multiple times a year in the Guangdong and Guangxi regions, comprising the following technical means:

[0009] (1) Harvest soybean pods at the R6 stage (peak grain filling stage), dry them at 40℃ for 3 days, and then peel out the soybeans for sowing;

[0010] (2) When the average daily temperature is below 18℃, build a greenhouse to keep the soybean plants warm;

[0011] (3) When sowing is required at a low temperature below 18℃, the seeds to be propagated should be placed in a 30℃ germination box for 2 days before sowing.

[0012] Furthermore, the above-mentioned breeding method is used to breed four-crop-a-year spring soybeans in the Guangdong and Guangxi regions, including the following steps:

[0013] Step 1, First season of seed propagation: Sow in early October of the first year, flower in early November, and harvest R6 stage (peak grain filling stage) pods in late January of the second year. Dry them at 40℃ for 3 days and then shell the beans to use as seed material for the second season.

[0014] Step 2, second season of propagation: In late January of the second year, the beans harvested in the first season are sown. The beans will flower in early March of the second year. In early April of the second year, the R6 stage (peak pod-filling stage) pods are harvested, dried at 40℃ for 3 days, and then the beans are shelled out as sowing material for the third season.

[0015] Step 3, third season of seed propagation: Sow the beans harvested in the second season in mid-April of the second year. The beans will flower in late May of the second year. Harvest the R6 stage (peak pod-filling stage) bean pods in late June of the second year. Dry them at 40℃ for 3 days and then shell the beans to use as seed material for the fourth season.

[0016] Step 4, fourth-season propagation: Sow the beans harvested in the third season in late June of the second year. The beans will flower in early August of the second year, and the R6 stage (peak pod-filling stage) pods can be harvested in mid-September of the second year. The beans will mature in late September of the second year.

[0017] Furthermore, the above-mentioned breeding method is used to breed summer soybeans that can be harvested three times a year in the Guangdong and Guangxi regions, including the following steps:

[0018] Step S1, First season of propagation: Sow in early July of the first year, flower from mid to late August of the first year, and harvest R6 stage (peak grain filling stage) pods from late September to early October of the first year. Dry them at 40℃ for 3 days and then shell the beans to use as sowing material for the second season.

[0019] Step S2, second season of propagation: Sow the beans harvested in the first season from late September to early October of the first year. Flowering occurs from early to mid-November of the first year. Harvest the R6 stage (peak pod-filling stage) bean pods in early January of the second year, dry them at 40℃ for 3 days, and then shell the beans to use as the sowing material for the third season.

[0020] Step S3, third-season seed propagation: Sow the beans harvested in the second season in mid-January of the second year. The beans will flower from mid-March to mid-April of the second year. The R6 stage (peak pod-filling stage) pods can be harvested from early May to early June of the second year. The beans will mature from mid-June to late June of the second year.

[0021] The beneficial effects of this invention are:

[0022] This invention combines techniques such as "R6 stage pod harvesting + 40℃ / 3-day drying + low-temperature seasonal greenhouse insulation and germination" to achieve four spring soybean harvests and three summer soybean harvests in the Guangdong and Guangxi regions without relying on southern breeding facilities. The breeding efficiency of spring soybeans is 100% higher than the conventional two-crop-a-year method and 33.33% higher than the existing three-crop-a-year method. The breeding efficiency of summer soybeans is 200% higher than the conventional one-crop-a-year method. This invention significantly reduces costs and greatly increases the number of breeding generations per unit time without the need for southern breeding facilities.

[0023] Instruction manual illustrations

[0024] Figure 1 Experimental results on timely pod harvesting to shorten the soybean breeding cycle

[0025] Figure 2 Experiment to accelerate the growth rate of soybeans propagated in winter using a simple greenhouse Detailed Implementation

[0026] The following embodiments further illustrate the content of the present invention, but should not be construed as limiting the present invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are within the scope of the present invention.

[0027] Example 1: Application of Spring Soybean Four-Crop-a-Year Breeding Technology

[0028] The soybean variety GC206 (Guichun 206) has an average growth period of 101±2.75 days when sown in spring (early March) and 92±2.22 days when sown in summer (early July) in Nanning. It belongs to the mid-to-late maturing spring soybean variety.

[0029] The first round of seed propagation trials for GC206 was conducted in Nanning on October 5, 2023. The first round of sowing took place in the field, with seedlings emerging on October 10 and flowering on November 4. On January 20, 2024, the pods were harvested and placed in mesh bags in a 40℃ electric heating drying oven for 3 days. The second round of seed propagation then proceeded; GC206 seeds were extracted from the pods, germinated at 30℃ for 2 days, and then planted in flowerpots on January 25, 2024, and placed in a simple greenhouse. Seedlings emerged on January 31. Flowering begins on March 1st. Pods are harvested on April 10th and dried in a 40℃ electric heating oven for 3 days before the third round of propagation. GC206 seeds are extracted from the pods, germinated, and then directly sown in the field on April 15th. Seedlings emerge on April 19th, flowering begins on May 23rd, and pods are harvested on June 25th. After drying in a 40℃ electric heating oven for 3 days, the fourth round of propagation begins, and seeds are directly sown in the field on June 29th. Seedlings emerge on July 3rd, flowering begins on August 9th, pods can be harvested on September 11th, and maturity begins on September 30th. When the average daily temperature is below 18℃, a greenhouse is built to keep the soybean plants warm. When sowing is required at temperatures below 18℃, the seeds to be propagated are first germinated in a 30℃ germination chamber for 2 days before sowing.

[0030] The mid-to-late maturing spring soybean variety GC206 can complete a four-crop-a-year propagation cycle in Nanning without the aid of Hainan's southern breeding program (Table 1).

[0031] Table 1. Growth of soybean GC206 at different growth stages during four harvests per year.

[0032]

[0033] Example 2: Application of Summer Soybean Three-Crop-a-Year Breeding Technology

[0034] Because summer soybeans cannot be sown in spring, previous breeding programs for summer soybeans in Guangxi Zhuang Autonomous Region could only be conducted in summer, achieving only one harvest per year. To accelerate the breeding process, it is necessary to utilize the Southern Breeding Program for multiple generations. In 2024, a multi-cropping trial was conducted using the mid-late maturing soybean variety GX7 (Guixia 7) and the late maturing soybean variety GX1902 (Guixia 1902) as materials. The average growth period for GX7 sown in summer (early July) was 104 days, while the average growth period for GX1902 sown in summer (early July) was 110 days.

[0035] Both GX7 and GX1902 were sown in Nanning on July 1, 2024, for the first round of seed propagation, with seedlings emerging on July 5. GX7 flowered on August 16, and after pod harvesting on September 25, the seeds were dried in a 40℃ electric heating oven for 3 days before the second round of seed propagation. Seedlings emerged in the field on October 4, and flowered on November 2. After pod harvesting on January 2, 2025, the seeds were dried in a 40℃ electric heating oven for 3 days and then air-dried. Sowing was carried out on January 14, 2025, with seedlings emerging on January 27, flowering on March 16, pod harvesting on May 6, and harvesting on June 15. Compared to summer sowing, winter-sown GX7 exhibits less leaf drop at maturity and matures more slowly. In the first round of seed propagation, GX1902 flowers on August 22, 2024. After pod harvesting on October 2, the seeds are dried in a 40℃ electric heating oven for 3 days and then directly sown in the field on October 6, 2024 for the second round of seed propagation. Seedlings emerge on October 11, flowering on November 15. Pods are harvested on January 1, 2025, and the seeds are dried in a 40℃ electric heating oven for 3 days. Sowing in the field on January 14 for the third round of seed propagation results in seedling emergence on January 27, flowering on April 13, pod harvesting on June 1, and harvesting on June 24, 2025. Compared to summer sowing, winter sowing of GX1902 exhibits good leaf drop. When the average daily temperature is below 18℃, a greenhouse should be built to keep the soybean plants warm. When sowing is required at temperatures below 18℃, the seeds to be propagated should first be germinated in a 30℃ germination chamber for 2 days before sowing.

[0036] Both GX7 and GX1902 can achieve three harvests a year in Nanning without the aid of Nanyang breeding (Table 2).

[0037] Table 2. Growth status of GX7 and GX1902 varieties during different growth stages in a three-crop-a-year year.

[0038]

[0039] Example 3: Experiment on shortening the soybean breeding cycle by timely pod harvesting

[0040] Using soybean varieties Guichun 15 (GC15) and GC206 (Guichun 206) as materials, soybeans were planted at the Mingyang Base of the Guangxi Academy of Agricultural Sciences on January 18, 2023. Each plot was 4m long and 1.2m wide, with 3 rows of soybeans planted in each plot, with a row spacing of 40cm and a plant spacing of 20cm. Three replicates were set. Both varieties emerged on January 29. The R1 (initiation of flowering) for GC206 and GC15 were March 25 and March 31, respectively; the R6 (peak grain filling) for GC206 and GC15 were May 7 and May 6, respectively; the R7 (initial maturity) for GC206 and GC15 were May 28 and May 25, respectively; and the R8 (full maturity) for GC206 and GC15 were June 2 and May 31, respectively. Soybean pods with uniformly fullness were placed in a 40℃ electric drying oven. Samples were taken on days 1, 2, 3, 4, 5, and 6 after drying. The dried samples, along with the control (CK), were stored in a 4℃ refrigerator for later use. After sample processing, the pods, along with the CK, were dehulled. Soybean seed germination was tested using the paper bed method as described in GB / T3543.4—1995 "Specifications for Crop Seed Inspection - Germination Test". Thirty intact seeds were placed in a germination box (length × width × height: 12 cm × 12 cm × 6 cm) lined with two layers of moist germination paper. Two more layers of moist germination paper were then placed on top, and the box was placed in a 25℃ germination chamber for germination. The number of germinated seeds and the number of normal seedlings were counted on days 3 and 5. Germination seed count: the number of seeds with a radicle length ≥ 1 cm; Normal seedling count: the number of seedlings with no obvious damage to the cotyledons, true leaf buds, hypocotyl, and roots. Then, referring to the method of Chen Wenjie et al. (2025), the germination potential and normal seedling rate of each treatment were calculated. Germination potential = (number of germinated seeds on day 3 / number of tested seeds) × 100%; Normal seedling rate = (number of normal seedlings / number of tested seeds) × 100%.

[0041] The experimental results show that at 40℃, with the extension of drying time, both the pod color and the grain color gradually change from green to yellow. Figure 1 As the soybeans gradually dehydrate and dry, the moisture content of the soybean seeds drops below 13% after 6 days of drying. The color change is most noticeable on the 3rd day, when the seeds change from green to yellow, and they begin to dehydrate, feeling noticeably soft when squeezed. Germination results show that GC206 and GC15 varieties had the lowest germination vigor and normal seedling rate with fresh pods, followed by those dried for 1 day. Drying for 2 days significantly improved germination vigor and normal seedling rate compared to fresh pods, with GC206 showing increases of 78.77% and 80.00% respectively, and GC15 showing increases of 64.45% and 67.78% respectively. Drying for 3 days resulted in the highest germination vigor and normal seedling rate (Table 3). Sowing GC206 and GC15 varieties 3 days after pod harvesting and drying at the R6 stage can advance sowing by at least 23 days and 22 days respectively.

[0042] Table 3. Effects of different drying times after pod harvesting on germination ability of GC206 and GC15 varieties.

[0043]

[0044] Example 4: High-Temperature Germination Accelerates Soybean Emergence Experiment

[0045] Using soybean varieties GC15 (Guichun 15) and GC206 (Guichun 206) as materials, a sowing experiment under different conditions was conducted at the Mingyang Base of the Guangxi Academy of Agricultural Sciences on January 15, 2023. T1: Direct sowing in the field; T2: Sowing in the field after germination in a 30℃ incubator for 2 days; T3: Sowing in flowerpots and placing them in a simple greenhouse; T4: Germination in a 30℃ incubator for 2 days, then planting in flowerpots and placing them in a simple greenhouse. Germination method: Soybean seeds were placed on three moistened sheets of tissue paper, wrapped, and then covered with a layer of moistened germination paper. The ends were then tied with rubber bands and placed in a 30℃ incubator for germination for 2 days. The experimental results showed that T1 emerged after 14 days, T2 after 9 days (including germination time), T3 after 8 days, and T4 after 5 days (including germination time). Under field conditions, germination was 5 days earlier than normal sowing and emergence, with a progress rate of 35.71%. Under greenhouse conditions, germination was 3 days earlier than normal sowing and emergence, with a progress rate of 37.50%.

[0046] Example 5: Accelerating the Growth Rate of Soybeans Propagated in Winter Using a Simple Greenhouse

[0047] Using soybean varieties GC15 (Guichun 15) and GC206 (Guichun 206) as materials, different planting environment experiments were conducted at the Mingyang Base of the Guangxi Academy of Agricultural Sciences on January 15, 2023. I1: Soybeans were planted in flowerpots and then placed in a simple greenhouse (…). Figure 2 I2: Soybeans were directly sown in the field. Results showed that under simplified greenhouse conditions, GC206 and GC15 flowered 21 and 23 days earlier, respectively, than under field conditions, and matured 22 days earlier on average (Table 2). Simplified greenhouse conditions under low temperature effectively accelerated soybean growth.

[0048] Table 4. Effects of a simple greenhouse on soybean growth

[0049] .

Claims

1. A breeding method of soybean for two years of maturity in Guangdong and Guangxi regions, characterized by, The technical means include the following: (1) picking the pods at the R6 stage of soybeans, drying them at 40℃ for 3 days, and then sowing the beans; (2) when the average temperature is lower than 18℃, building a greenhouse to keep the soybean plants warm; (3) when sowing is needed under the condition that the temperature is lower than 18℃, first germinating the seeds to be bred in a 30℃ germination box for 2 days, and then sowing them.

2. The breeding method according to claim 1, characterized by, The breeding method is used to breed one-year four-crop spring soybeans in Guangdong and Guangxi, and includes the following steps: Step one, first-season breeding: sowing in early October of the first year, flowering in early November, picking the R6-stage pods in late January of the second year, drying them at 40℃ for 3 days, and then sowing the beans as the sowing material for the second season; Step two, second-season breeding: sowing the beans picked in the first season in late January of the second year, flowering in early March, picking the R6-stage pods in early April, drying them at 40℃ for 3 days, and then sowing the beans as the sowing material for the third season; Step three, third-season breeding: sowing the beans picked in the second season in mid-April of the second year, flowering in late May, picking the R6-stage pods in late June, drying them at 40℃ for 3 days, and then sowing the beans as the sowing material for the fourth season; Step four, fourth-season breeding: sowing the beans picked in the third season in late June of the second year, flowering in early August, picking the R6-stage pods in mid-September of the second year, and harvesting them in late September of the next year.

3. The breeding method according to claim 1, characterized by, The breeding method is used to breed one-year three-crop summer soybeans in Guangdong and Guangxi, and includes the following steps: Step S1, first-season breeding: sowing in early July of the first year, flowering from mid-August to late August, picking the R6-stage pods from late September to early October, drying them at 40℃ for 3 days, and then sowing the beans as the sowing material for the second season; Step S2, second-season breeding: sowing the beans picked in the first season from late September to early October of the first year, flowering from early November to mid-November, picking the R6-stage pods in early January of the second year, drying them at 40℃ for 3 days, and then sowing the beans as the sowing material for the third season; Step S3, third-season breeding: sowing the beans picked in the second season in mid-January of the second year, flowering from mid-March to mid-April, picking the R6-stage pods from early May to early June, and harvesting them from mid-June to late June of the second year.

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