Oat glume-shearing hybridization method for improving maturing rate and application of oat glume-shearing hybridization method

Abstract

The invention discloses an oat glume-cutting hybridization method capable of increasing the maturing rate and application thereof.According to the oat glume-cutting hybridization method, by conducting castration and glume-cutting treatment on a first main grain of an outermost spikelet of each round layer in a female parent, it can be guaranteed that ovules obtained after artificial hybridization pollination have sufficient nutrition for grain filling according to the oat fruiting nutrition distribution rule; female parents are bagged after castration and glume cutting, the bagging time is controlled to be 12-24 h, the water content of the fluff surface of the stigma can be reduced (it is prevented that pollen is separated by a water film when falling on the stigma), the contact area of the pollen and the stigma is increased, and the germination rate of pollen tubes is increased; pollination is carried out when the male parent anther naturally cracks, that is, pollination is carried out in the period with the maximum pollen viability, and the cross pollination probability can be increased. According to the method, the hybridization maturing rate can be remarkably increased, and the hybridization maturing rate can reach 70% or above when the white swallow No. 2 is used as the female parent and the white swallow No. 7 is used as the male parent for hybridization.

Description

Technical Field

[0001] The present invention relates to the technical field of oat cultivation, and particularly relates to an oat glume-clipping hybridization method for improving the seed setting rate and its application. Background Art

[0002] Hybridization is a process that achieves this goal through the mutual fusion of germ cells. During hybridization, the pollen of the male parent is brought into contact with the stigma of the female parent. After the pollen scatters on the stigma of the female parent, the pollen germinates to form a pollen tube and enters the ovule through the micropyle. The end of the pollen tube begins to rupture, and one sperm cell combines with the egg cell to form a fertilized egg, while the other sperm cell combines with the polar nuclei to form a fertilized polar nucleus, thus completing the entire hybridization fertilization process. Currently, mainly through hybridization breeding technology, the excellent traits of different oat varieties are organically combined to cultivate new oat varieties with more excellent traits and better able to meet the production and market demands. During the current oat hybridization process, in addition to being affected by the external environment, it is also easily affected by factors such as pollen viability and uneven nutrient distribution in the spikelets after pollination, resulting in a low hybridization seed setting rate and a low success rate of artificial cross-pollination. Summary of the Invention

[0003] Therefore, based on the above background, the present invention provides an oat glume-clipping hybridization method for improving the seed setting rate and its application.

[0004] The technical solution of the present invention is as follows:

[0005] An oat glume-clipping hybridization method for improving the seed setting rate, which comprises the following steps:

[0006] S1: Select oats of different varieties or germplasm resources as the female parent and the male parent respectively for sowing and planting;

[0007] S2: When the oats reach the heading stage, emasculate and clip the glumes of the first main grain of the outermost spikelet in each whorl of the female parent; and bag the emasculated and glume-clipped female parent;

[0008] S3: Take out the anthers that are about to dehisce from the male parent, and after they naturally dehisce, pollinate them onto the stigma of the female parent;

[0009] S4: Bag the pollinated female parent until the pollinated spikelets grow grains.

[0010] Further, the specific operation of emasculating and clipping the glumes of the female parent in step S2 is as follows:

[0011] When half of the oat spike emerges from the leaf sheath, remove the uppermost spikelet that has already been cleistogamously pollinated, and only retain the first main grain of the outermost spikelet in the whorl that has not been self-pollinated, and remove the other grains in the spikelet;

[0012] Pull open the lemma of the first main grain for emasculation. After emasculation, arrange the glumes and lemma and palea well and perform glume cutting. The height of glume cutting is reserved at 1-2 mm above the stigma.

[0013] Further, the duration of bagging the female parent in step S2 is 12-24 h.

[0014] Further, in step S3, find the naturally cracked anthers of the male parent during 10:00 to 15:00 in the morning, take out the yellowish-white anthers about to crack from the male parent spikelet, and pour the pollen onto the stigma of the female parent after glume cutting when the anthers naturally crack, thus completing the artificial cross-pollination.

[0015] Based on the same inventive concept, the present invention also applies the above-mentioned oat glume-cutting hybridization method for improving the seed setting rate to oat cross-breeding.

[0016] The effective effects achieved by the present invention are as follows:

[0017] The present invention firstly emasculates and performs glume cutting on the first main grain of the outermost spikelet in each whorl of the female parent, and can utilize the oat seed setting nutrient distribution rule to ensure that the ovules after artificial cross-pollination have sufficient nutrients for grain filling;

[0018] After emasculation and glume cutting, the present invention performs bagging treatment on the female parent, and reasonably controls the bagging duration within 12-24 h, so as to increase the contact area between pollen and stigma and improve the pollen tube germination rate by reducing the water content on the surface of the stigma villi (preventing a water film from separating when pollen lands on the stigma);

[0019] The present invention performs pollination when the anthers of the male parent naturally crack, that is, selects the period with the highest pollen viability for pollination, which can improve the cross-pollination probability.

[0020] The present invention can significantly improve the cross seed setting rate. Through experimental verification, when using Baiyan No. 2 variety as the female parent and Baiyan No. 7 as the male parent for hybridization, the cross seed setting rate can be increased to more than 70%.

[0021] Explanation of the drawings

[0022] Appendix Figure 1 It is a picture of the female parent after emasculation and glume cutting in the embodiment of the present invention;

[0023] Appendix Figure 2 It is a picture of the naturally cracked anthers of the male parent in the embodiment of the present invention;

[0024] Appendix Figure 3 It is a picture of oat cross-authorized seed setting in the embodiment of the present invention. Detailed implementation manners

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with its embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] Embodiment 1: A method for oat glume hybridization to improve the seed setting rate, which comprises the following steps:

[0027] S1: Select oats of different varieties or germplasm resources as female and male parents respectively and sow them for planting;

[0028] S2: At the heading stage of oats: emasculate and glume the first main grain of the outermost spikelet of each whorl of the female parent; and bag the emasculated and glumed female parent.

[0029] In this step, the duration of bagging the female parent is 12 - 24h.

[0030] The specific operation of emasculating and gluming the female parent in this step is as follows:

[0031] When half of the oat spike emerges from the leaf sheath, remove the uppermost spikelet that has already been self-pollinated, and only retain the first main grain of the outermost spikelet of the whorl that has not been self-pollinated, and remove other grains in the spikelet.

[0032] Separate the lemma of the first main grain to emasculate, and after emasculation, arrange the glumes and lemma and palea well and perform gluming treatment, and the gluming height is reserved at 1 - 2mm above the stigma.

[0033] Oat spikelets preferentially allocate nutrients to the outermost spikelet of each whorl during the grain filling period. Although oats have a large number of spikelets, the nutrient allocation rule during filling is from the top to the bottom, and nutrients are allocated from the outermost to the innermost spikelet of each whorl. Therefore, not every floret in each spikelet can obtain normal nutrient allocation and set seeds. For example, the seed setting rate of the lower spikelets and the inner spikelets of the whorl of normally growing oats is very low. Therefore, the present invention selects the top spikelets and the outermost spikelets of the whorl in the female parent for emasculation hybridization, and can utilize the oat seed setting nutrient allocation rule to ensure that the ovules after artificial cross-pollination have sufficient nutrients for grain filling, so as to improve the cross seed setting rate.

[0034] And the present invention selects a suitable gluming height. Specifically, the gluming height needs to be 1 - 2mm higher than the stigma, and the seed setting rate is the highest in this case. The main reason for the analysis is that after emasculation and gluming, the glume of the female parent will show water loss and wilting. If the gluming height is too high, the lemma of the female parent wilts severely and will wrap the stigma. When pollinating, it is necessary to use tweezers to separate the wilted glume and lemma, and it is easy to damage the stigma while separating the glume and lemma. If the gluming height is too low, less than 1mm, it is easy to cut the stigma during gluming, and the damage to the stigma will greatly reduce the pollination success rate.

[0035] The spikelets selected for emasculation of the female parent are emasculated before the anthers of the female parent shed pollen, and the stigmas must be fluffy. Firstly, the stigmas must be in the mature stage of development. Secondly, emasculation must be carried out before self-pollination. After emasculation and glume cutting, since the humidity inside the glumes is relatively high and there is a certain water film on the fluffy stigmas, this is generally one of the reasons for the low seed setting rate during the normal growth of oats. When self-pollination occurs, the seed setting rate is not high due to the influence of the humidity inside the self-glumes. Therefore, through continuous attempts, the present invention finally found that after bagging the female parent after emasculation and glume cutting for 12 - 24 hours, the pollination success rate is the highest. Analyzing the reasons, firstly, glume cutting reduces the moisture on the stigmas, which can prevent the contact between pollen and stigmas during pollination and restrict the pollen tubes of pollen from germinating and penetrating deep into the ovules along the stigmas. Secondly, if the bagging waiting time is too long, after glume cutting, the palea shrinks and is likely to clamp the stigma in the retroflexure of the palea, severely wrapping the stigma and restricting the contact area between pollen and stigmas during pollination, thus reducing the pollination success rate.

[0036] Specifically, the upper heading stage is 80 - 90 days after oat planting.

[0037] S3: Take out the anthers about to dehisce from the male parent. After natural dehiscence, pollinate the stigmas of the female parent with the pollen.

[0038] In this step, during the oat pollen shedding time from 10:00 am to 15:00 pm, find the naturally dehisced anthers of the male parent, take out the yellowish-white anthers about to dehisce from the florets of the male parent, and when the anthers naturally dehisce, pour the pollen onto the stigmas of the female parent after glume cutting, thus completing the artificial cross-pollination.

[0039] In traditional cross-pollination operations, generally, the anthers are placed into the florets of the emasculated female parent without glume cutting, or the anthers are crushed and then placed into the florets. However, if the anthers are directly removed from the filaments without normal maturity and directly placed into the florets, some anthers may not dehisce normally to shed pollen, which greatly reduces the pollination probability of the stigmas. Also, when the anthers are crushed and placed into the florets, since the anthers do not reach the normal maturity stage of natural dehiscence and pollen shedding, the pollen in the anthers is not fully mature when pollinated onto the stigmas, which also reduces the pollination probability of the stigmas. Therefore, compared with traditional pollination operations, the present invention selects the anthers about to dehisce, takes them out from the male parent, and pollinates the stigmas of the female parent after natural dehiscence, so as to ensure that the pollen is in the best vitality state and thus guarantee the cross-pollination success rate.

[0040] S4: Bag the pollinated female parent until the florets with pollination grow grains, and then the bags can be removed.

[0041] In steps S3 and S4 of this embodiment, the bags used for bagging are opaque paper bags.

[0042] Example 2: This was carried out at the Taohe oat base in Baicheng City, using Baiyan 2 as the female parent and Baiyan 7 as the male parent for hybridization.

[0043] S1: Sow and plant the male parent and the female parent separately;

[0044] S2: 80-90 days after planting, at the heading stage of oats, the first main grain of the outermost spikelet of each whorl of the female parent is emasculated and the lemma is cut; the female parent after emasculation and lemma cutting is bagged; the bagging time of the female parent in this step is 24 hours.

[0045] The specific operation of emasculating and trimming the female parent in this step is as follows:

[0046] When half of the leaf sheath is pulled out of the oat ear, the uppermost spikelet that has been closed-pollinated is removed, and only the first main grain is retained for the outermost spikelet of the whorl layer that has not been self-pollinated, and the other grains in the spikelet are removed;

[0047] Remove the inner ramets of the first main grain and perform emasculation. After emasculation, tidy up the guard ramets and the inner and outer ramets and trim the ramets. The trimming height should be kept 1-2mm above the stigma.

[0048] S3: Take out the anthers of the male parent that are about to dehisce, wait for them to dehisce naturally, and then pollinate them on the stigma of the female parent;

[0049] In this step, the naturally dehiscing anthers of the male parent are found between 10 am and 15 pm, the yellow-white anthers that are about to dehisce are taken out from the spikelets of the male parent, and when the anthers dehisce naturally, the pollen is poured into the stigma of the female parent after clipping, thus completing the artificial hybridization pollination.

[0050] S4: Bag the pollinated female parent until the pollinated spikelets grow grains, then remove the bags.

[0051] In the present embodiment, the bag used for bagging in steps S3 and S4 is an opaque paper bag.

[0052] Embodiment 2: Compared with Embodiment 1, the bagging time of the mother parent in step S2 is controlled at 12 hours, and the other operation steps are the same.

[0053] Embodiment 3: Compared with Embodiment 1, in this embodiment, the bagging time of the mother parent in step S2 is controlled at 48 hours, and the other operation steps are the same.

[0054] Comparative Example 1: Compared with Example 1, the operation of trimming and emasculating in step S2 is as follows:

[0055] The first main grain floret was emasculated on the spikelet of the oat ear (the traditional emasculation position of the female plant), and the rest of the operations were the same.

[0056] Comparative Example 2: Compared with Example 1, the operation of cutting the glumes and emasculating in step S2 is as follows: Cut off the spikelets on the ear from the top, and remove the second and third florets and the anthers in the first floret in the spikelets, and the other operations are the same.

[0057] Comparative Example 3: Compared with Example 1, the cutting height of the glumes in step S2 is reserved at 4 - 5 mm above the stigma, and the other operation steps are the same.

[0058] Comparative Example 4: Compared with Example 1, the cutting height of the glumes in step S2 is reserved flush with the stigma.

[0059] Comparative Example 5: Compared with Example 1, the cutting height of the glumes in step S2 is reserved at 0.5 mm - 0.8 mm on the stigma.

[0060] Comparative Example 6: Compared with Example 1, the bagging time of the female parent in step S2 is controlled at 72 h, and the other operation steps are the same.

[0061] Comparative Example 7: Compared with Example 1, the bagging time of the female parent in step S2 is controlled at 96 h, and the other operation steps are the same.

[0062] Comparative Example 8: Compared with Example 1, the bagging time of the female parent in step S2 is controlled at 120 h, and the other operation steps are the same.

[0063] The fruiting time (starting from bagging after pollination) and the fruiting rate (fruiting rate = number of fruiting florets × 100% / number of emasculated florets) of Examples 1 to 3 and Comparative Examples 1 to 8 were respectively statistically analyzed, and the results are shown in Table 1 below.

[0064] Table 1: Statistical results of fruiting rate

[0065]

[0066] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for increasing oat cutting hybridization rate, characterized in that: It includes the following steps: S1: Select oats of different varieties or germplasm resources as female and male parents for sowing and planting respectively; S2: When the oats are in the heading stage, the first main grain of the outermost spikelet of each whorl layer of the female parent is emasculated and the glume is cut off; the emasculated and glume-cut female parent is bagged; S3: Take out the anthers of the male parent that are about to dehisce, wait for them to dehisce naturally, and then pollinate them on the stigma of the female parent; S4: Bag the pollinated female parent until the pollinated spikelets grow grains.

2. The oat cutting hybridization method for improving the fruit setting rate according to claim 1, characterized in that: The specific operation of step S2 for emasculating and trimming the female parent is as follows: When half of the leaf sheath is pulled out of the oat ear, remove the uppermost spikelet that has been closed pollinated, and only retain the first main grain of the outermost spikelet of the whorl layer that has not been self-pollinated, and remove the other grains in the spikelet; Remove the inner ramets of the first main grain and perform emasculation. After emasculation, tidy up the guard ramets and the inner and outer ramets and trim the ramets. The trimming height should be kept 1-2mm above the stigma.

3. The oat cutting hybridization method for improving the fruit setting rate according to claim 2, characterized in that: The duration of bagging the parent in step S2 is 12-24 hours.

4. The oat cutting hybridization method for improving the fruit setting rate according to claim 1, characterized in that: In step S3, the naturally dehiscing anthers of the male parent are searched between 10 am and 15 pm, the yellow-white anthers about to dehisce are taken out from the spikelets of the male parent, and when the anthers dehisce naturally, the pollen is poured into the stigma of the female parent after clipping, thus completing the artificial hybridization pollination.

5. Use of the oat clipping hybridization method for improving the fruit setting rate according to any one of claims 1 to 4 in oat hybrid breeding.

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