Efficient cross pollination method for pecan plants

Abstract

The invention relates to the technical field of plant breeding, in particular to an efficient cross pollination method for pecan plants. The pollination method comprises the steps of pollen collection, bagging and pollination. A bag used in the bagging process is a transparent plastic self-sealing bag, and the specification of the transparent plastic self-sealing bag is (4-8) cm * (6-12) cm; the pecan plants are hermaphroditic and different-flower pecan plants. According to the cross pollination method suitable for the carya illinoensis, transparent plastic self-sealing bags with appropriate specifications are used in the bagging stage, on one hand, whether female flowers reach a pollination state or not and the development state of the female flowers after pollination can be visually confirmed, and the photosynthesis of carya illinoensis leaves in the bags is not affected; on the other hand, injection pollination can be directly facilitated, and the pollination efficiency and the maturing rate are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of plant breeding, and in particular to a high-efficiency cross-pollination method for Carya plants. Background Art

[0002] Carya illinoinensis is a plant of the genus Carya in the family Juglandaceae. It is an important dried fruit and woody oil tree species worldwide. In the early days, Carya illinoinensis was often used as a greening tree species, and later it was used for fruit. The commercial name of Carya illinoinensis is pecans. Its nuts have a high oil content, of which unsaturated fatty acids account for more than 90% of the total fat content. It also contains rich phenolic substances, mineral elements, amino acids, vitamins, etc., and is rich in nutrition and high in economic value. In recent years, Carya illinoinensis has been widely planted. However, most of the current varieties of Carya illinoinensis are introduced from abroad, and the number of independently bred varieties is small. Therefore, it is urgent to speed up breeding work.

[0003] Hybrid breeding is the main breeding method for agricultural and forestry crops. The thin-shelled pecan has monoecious flowers, male and female flowers mature differently, and flowers are wind-pollinated. The artificial hybridization pollination process mainly includes six steps: (1) When the male inflorescence of the male parent turns yellow and is about to shed pollen, collect the male inflorescence, scatter pollen in a cool place, take the pollen and put it into a 10 ml centrifuge tube, seal it and store it in a refrigerator at 4°C for later use; (2) Before the female flower is available for pollination, use a sulfuric acid paper bag to bag it and use a paper clip or stapler to seal and fix it to prevent pollen contamination; (3) During the female flower's fertilization period, remove the pollination bag; (4) Use a cotton swab, ear cleaning bulb or rubber-tipped dropper to dip (suck) an appropriate amount of pollen and apply or spray it on the stigma; (5) After pollination is completed, put the pollination bag back on and seal and fix it with a paper clip or stapler; (6) After the female flower is successfully pollinated and the stigma turns black, remove the pollination bag. However, the thin-shelled pecan is a tall tree, and the entire hybrid pollination process involves bagging and unbagging four times, which is cumbersome, difficult, and inefficient. The process of spraying and applying pollen with cotton swabs, ear bulbs, or rubber-tipped droppers can easily cause stigma damage, affecting the fruit set rate. The sulfuric acid paper bag has poor light transmittance, which affects leaf photosynthesis, and increases the risk of pollen contamination from other varieties during bag unpacking and pollination.

[0004] Therefore, it is urgent to establish a hybrid pollination method for thin-shell walnuts that is simple to operate, has high pollination efficiency and high fruit setting rate. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides an efficient hybrid pollination method for Carya plants.

[0006] In a first aspect, the present invention provides a method for efficient cross-pollination of plants of the genus Carya, comprising:

[0007] collecting pollen, bagging and pollinating;

[0008] The bag used in the bagging process is: a transparent plastic ziplock bag, with a specification of: (4-8) cm × (6-12) cm;

[0009] The Carya plant is a monoecious Carya plant with different flowers.

[0010] Furthermore, the transparent plastic ziplock bag is a transparent bag made of plastic material. For example, the transparent plastic ziplock bag can be sealed with a self-contained zipper, without the need to use additional paper clips or staples to seal it like a paper bag.

[0011] In order to prevent contamination by pollen of other varieties before pollination, it is necessary to bag the female flowers before they mature. Transparent bags can directly observe and judge whether the female flowers are ready for pollination. There is no need to remove the bags before judging, which can improve the pollination efficiency. In addition, transparent bags do not affect the photosynthesis of thin-shelled pecan leaves in the bags. However, not all forms of transparent plastic bags are feasible. Larger ziplock bags are heavier, and if the female inflorescence is covered alone, the inflorescence will be crushed. Therefore, the leaves around the female flowers need to be covered. In this way, due to the transpiration of the leaves, there will be a lot of water vapor in the ziplock bag, and there will be moisture on the stigma. After spraying, the pollen quickly absorbs water and bursts, and the success rate of pollination is reduced. The ziplock bags with slightly smaller specifications can cover the female inflorescence alone, and there is less steam in the bag.

[0012] Furthermore, the bagging comprises:

[0013] Before the female flowers of the pecan plant reach the pollination stage, the transparent plastic bag is used for bagging, and after bagging, the state of the female flowers is observed through the transparent plastic bag until the female flowers reach the pollination stage.

[0014] Further, the pollination comprises:

[0015] For the bagged female flowers that have reached the pollination stage, a syringe filled with pollen is used to pierce the transparent plastic bag and then pollinate the stigma.

[0016] Furthermore, the specification of the syringe is: 5-15 mL. Furthermore, the syringe is a 10 mL plastic disposable syringe.

[0017] The present invention uses a syringe for pollination, which can hold a specific volume of pollen, making it easy to control the amount of pollen, and the injection needle is slender and can directly pierce the transparent ziplock bag, simulating wind pollination, and spraying pollen on the stigma of the female flower without contact, thereby avoiding stigma damage. In addition, the present invention uses a syringe to directly pollinate, avoiding the bag unpacking process, and can improve the pollination efficiency while avoiding potential pollen contamination during the bag unpacking process.

[0018] Further, collecting pollen includes:

[0019] Collect pollen in a ventilated and cool environment and pass it through an 80-120 mesh sieve.

[0020] Furthermore, collecting pollen in a ventilated and cool environment includes:

[0021] Turn on the dehumidification mode of the air conditioner in the indoor environment, set the temperature to 22-25℃, and collect pollen after 12-24 hours.

[0022] Furthermore, before collecting pollen, the method further includes: collecting the male inflorescence of the Carya genus plant when the male inflorescence turns yellow and is about to shed pollen.

[0023] The pollination method provided by the present invention is particularly suitable for the monoecious and dioecious pecan plant, namely, the thin-shell pecan. On the one hand, the thin-shell pecan has dioecious flowers, and the transparent ziplock bag is used for bagging, and the male and female flowers do not need to be removed, and the male and female flowers can be completely separated. On the other hand, the female inflorescence of the thin-shell pecan is spike-shaped and upright, and the inflorescence axis is relatively long. The smaller ziplock bag can cover the entire inflorescence alone, and the larger ziplock bag can cover the female inflorescence and the surrounding leaves. In addition, the thin-shell pecan is a wind-pollinated flower with a large amount of pollen and light weight, which is suitable for syringe spraying.

[0024] In a second aspect, the present invention provides application of the pollination method in improving the fruit setting rate of thin-shell pecans.

[0025] The present invention further provides application of the pollination method in improving the pollination efficiency of thin-shell pecans.

[0026] The present invention has the following beneficial effects:

[0027] The invention provides a pollination method for thin-shell pecans, which is bagged with a transparent plastic bag of a specific specification, so that the state of the plant can be directly observed before pollination, and pollination can be started at an accurate time. In addition, the transparent plastic bag will not affect the photosynthesis of the leaves therein. The hybrid pollination method provided by the invention can also effectively improve the pollination efficiency, shorten the pollination time, and significantly improve the fruit setting rate, which is of great significance in the field of pecan plant breeding. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1It is a schematic diagram of male and female flowers of thin-shell pecans provided in Example 1 of the present invention; wherein, from left to right, they are male flowers that are about to shed pollen; female flowers that are about to bloom; female flowers that are blooming and have reached the period of fertilization; and female flowers that have completed pollination.

[0030] Figure 2 The invention provides a traditional cross pollination and efficient pollination procedure for thin-shell pecans, wherein in the traditional cross pollination method, 1 is to cover the female flowers with a sulfuric acid paper tape and fix them with a paper clip or a stapler; 2 is to remove the bag and prepare for pollination; 3 is to use a rubber-tipped dropper to absorb pollen and then spray pollen; 4 is to re-bag after pollination and seal it with a stapler; in the efficient cross pollination method, 1 is to cover the female flowers with a transparent ziplock bag, and 2 is to use a syringe to inject and spray pollen when the female flowers reach the pollinable period. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The experimental methods involved in the following examples, unless otherwise mentioned, can be carried out using conventional methods in the art.

[0033] Unless otherwise specified, the experimental materials involved in the following examples can be purchased commercially.

[0034] Example 1

[0035] This embodiment provides a method for efficient cross-pollination, including the following process:

[0036] 1. Pollen collection

[0037] (1) When the male inflorescence of the male parent turns yellow and is about to shed pollen, collect the male inflorescence (the male flowers that are about to shed pollen are as follows: Figure 1 )

[0038] (2) Place in a ventilated and cool place or turn on the air conditioner in dehumidification mode (25°C) indoors, and the male flowers will shed pollen after 12 to 24 hours;

[0039] (3) Collect pollen, sieve through a 100-mesh sieve to remove impurities, put the pollen into a 10-mL centrifuge tube, seal it, and store it in a 4°C refrigerator until use.

[0040] 2. Bagging of female flowers before pollination and observation of development period

[0041] (1) Observe the phenological period of female flowers;

[0042] (2) Before the female flowers reach the reproductive period, use a transparent plastic ziplock bag to bag them and pinch the seal to prevent contamination from other pollen (for female flowers that are about to open, such as Figure 1 (as shown in the second left figure in the figure).

[0043] (3) Observe the development of female flowers through the transparent ziplock bag 4 days after bagging. Due to temperature changes, the time it takes for female flowers to reach the reproductive stage varies. It takes about 7 days for female flowers to reach the reproductive stage (if female flowers reach the reproductive stage, Figure 1 (as shown in the third left figure in Figure 1).

[0044] 3. Pollination process

[0045] (1) Pour an appropriate amount of pollen into the syringe needle;

[0046] (2) Aim the needle at the stigma of the pollinable period, puncture the transparent ziplock bag and spray pollen onto the stigma.

[0047] 4. Post-pollination treatment

[0048] (1) About 7 days after pollination, observe the stigma through the transparent ziplock bag. The stigma of the pollinated and fertilized flowers will turn black (the female flowers that have completed pollination will be Figure 1 as shown in the rightmost figure in );

[0049] (2) Carefully remove the transparent ziplock bag, randomly select 30 female inflorescences, and label them with labels to accurately indicate the number of female flowers;

[0050] (3) At the end of September, when the fruits are about to mature, count the number of fruits on 30 female inflorescences and divide the number of fruits by the number of female flowers to calculate the fruit set rate.

[0051] Comparative Example 1

[0052] This comparative example provides a traditional hybrid pollination method, which specifically includes the following process:

[0053] 1. Pollen collection

[0054] (1) Collect the male inflorescence when it turns yellow and is about to shed pollen;

[0055] (2) Place in a ventilated and cool place or turn on the air conditioner in dehumidification mode (25°C) indoors, and the male flowers will shed pollen after 12 to 24 hours;

[0056] (3) Collect pollen, sieve through a 100-mesh sieve to remove impurities, put the pollen into a 10-mL centrifuge tube, seal it, and store it in a 4°C refrigerator until use.

[0057] 2. Bagging of female flowers before pollination and observation of development period

[0058] (1) Observe the phenological period of female flowers;

[0059] (2) Before the female flowers reach the reproductive stage, use a paper bag to bag them and seal and secure them with a paper clip or stapler to prevent contamination by other pollen;

[0060] (3) Four days after the female flowers were bagged, 10 hybridization bags were randomly opened to observe the development status of the female flowers. Due to temperature changes, the time it takes for the female flowers to reach the receptive period varies. About 90% of the female flowers reach the receptive period in about 7 days. For the bouquets that do not reach the receptive period, the hybridization bags are quickly put back and sealed.

[0061] 3. Pollination process

[0062] (1) Use a rubber-tipped dropper to absorb an appropriate amount of pollen;

[0063] (2) Carefully remove the pollination bag and use a rubber-tipped dropper to spray pollen onto the stigma;

[0064] (3) After pollination is completed, quickly put the pollination bag back on and seal and secure it with a paper clip or stapler;

[0065] 4. Post-pollination treatment

[0066] (1) About 7 days after pollination, randomly open 10 hybridization bags and observe the stigma status. The stigma of the flowers that have completed pollination and fertilization will turn black. For the flowers that have not turned black, quickly put the hybridization bags back and seal them;

[0067] (2) Carefully remove the sulfuric acid paper bag, label it with a label, randomly select 30 female inflorescences, and accurately mark the number of female flowers;

[0068] (3) At the end of September, when the fruits are about to mature, count the number of fruits on 30 female inflorescences and divide the number of fruits by the number of female flowers to calculate the fruit set rate.

[0069] Test Example 1

[0070] This test example compares the pollination efficiency of Example 1 and Comparative Example 1 (the pollination process of Example 1 and Comparative Example 1 is as follows Figure 2 The specific process includes the following:

[0071] 1. Experimental Materials

[0072] 20 thin-shell pecans were taken and divided into two groups. The first group consisted of 15 plants, divided into three treatments (small bag, medium bag, and large bag), wherein each treatment group used a transparent plastic ziplock bag, the small bag group was 4 cm × 6 cm; the medium bag was 8 cm × 12 cm; and the large bag was 17 cm × 25 cm. The second group was a control group with a total of 5 plants, and the traditional cross pollination shown in Comparative Example 1 was used.

[0073] 2. Experimental methods

[0074] Pollination was carried out according to the methods of Example 1 and Comparative Example 1, and the pollination was timed from the time when pollen was absorbed until all plants were pollinated and bagged (pollination of 30 bunches of female flowers was completed).

[0075] 3. Experimental results

[0076] The results showed that the average pollination time for each of the 30 female flowers in the efficient pollination group shown in Example 1 was 11.18 seconds, and the average pollination time for each of the 30 female flowers in the traditional pollination group shown in Comparative Example 1 was 68.62 seconds.

[0077] Test Example 2

[0078] This test case compares the fruit set rate of pollination bags of different specifications for high-efficiency hybrid pollination and traditional hybrid pollination, including the following process:

[0079] 1. Observe the phenological period of female flowers and put on hybridization bags before the female flowers can be fertilized;

[0080] 2. Use small, medium and large plastic transparent ziplock bags (the same specifications as in Test Example 1) and sulfuric acid paper bags (sulfuric acid paper bags have similar specifications to medium transparent ziplock bags) as hybridization bags, and each hybridization bag has 30 bunches of female flowers;

[0081] 3. For the bouquets in transparent ziplock bags, pollinate them using the efficient pollination method. For the bouquets in sulfuric acid paper bags, pollinate them using the traditional method. Label each bouquet with female flowers and indicate the number of female flowers.

[0082] 4. Count the fruit setting rate of the listed female bouquets when they are about to enter maturity;

[0083] 5. The results showed that the fruit set rate of small size (46%) > medium size (40%) > large size (32%), and the fruit set rate of large size transparent ziplock bags was equivalent to that of traditional sulfuric acid paper bags (31%).

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly efficient cross-pollination method for Carya plants, characterized in that: include: collecting pollen, bagging and pollinating; The bag used in the bagging process is: a transparent plastic ziplock bag, with a specification of: (4-8) cm × (6-12) cm; The Carya plant is a monoecious Carya plant with different flowers.

2. The pollination method according to claim 1, characterized in that: The Carya genus plant is Carya calathea.

3. The pollination method according to claim 1 or 2, characterized in that: The bagging comprises: Before the female flowers of the pecan plant reach the pollination stage, the transparent plastic bag is used for bagging, and after bagging, the state of the female flowers is observed through the transparent plastic bag until the female flowers reach the pollination stage.

4. The pollination method according to claim 1 or 2, characterized in that: The pollination comprises: For bagged female flowers that have reached the pollination stage, a syringe filled with pollen is used to pierce the transparent plastic bag and then pollinate the stigma.

5. The pollination method according to claim 4, characterized in that: The specification of the syringe is: 5 to 15 mL.

6. The pollination method according to claim 1 or 2, characterized in that: The collecting of pollen comprises: Collect pollen in a ventilated and cool environment and pass it through an 80-120 mesh sieve.

7. The pollination method according to claim 6, characterized in that: The method of collecting pollen in a ventilated and cool environment comprises: Turn on the dehumidification mode of the air conditioner in the indoor environment, set the temperature to 22-25℃, and collect pollen after 12-24 hours.

8. The pollination method according to claim 1 or 2, characterized in that: Before collecting pollen, the method further comprises: collecting the male inflorescences of the genus Carya when the male inflorescences of the plant turn yellow and are about to shed pollen.

9. Use of the pollination method according to any one of claims 1 to 8 in improving the pollination efficiency of Carya sylvestris.

10. Use of the pollination method according to any one of claims 1 to 8 in improving the fruit setting rate of Carya calathea.

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