A method for solving the abortion of potato varieties as male parents in hybridization

Abstract

The present invention discloses a method for solving the abortion of potato varieties as hybrid male parents, which includes several steps such as the cultivation and selection of rootstocks, the cultivation of scions, grafting, post-graft management, cross-pollination, and harvesting of true seeds. The present invention grafts the potato variety Jizhangshu No. 3 as the scion with Jizhangshu No. 8 as the rootstock into one entity, and then uses the grafting community of Jizhangshu No. 8 and Jizhangshu No. 3 as the male parent to cross with Jizhangshu No. 8 as the female parent to achieve the purpose of normal fruit set after pollination, and solves the problem of flower sterility of potato Jizhangshu No. 3 as a hybrid male parent.

Description

Technical Field

[0001] The invention relates to the technical field of potato breeding, and in particular to a method for solving the problem of potato varieties being sterile as hybrid male parents. Background Art

[0002] Potatoes are native to the Andes Mountains in South America. my country has limited potato germplasm resources, but some of them still cannot bloom and bear fruit normally: for example, the potato variety Ji Zhang Shu No. 3 was bred by the Potato Research Laboratory of the Bashang Agricultural Science Institute in Zhangjiakou City. This variety has great production potential, high rate of large potatoes, good potato shape, smooth skin, few and shallow buds, non-protruding tops, and non-depressed navels, which is suitable for sale in southern my country. At the same time, it has a wide range of adaptability in the northern single-crop area, the central plains double-crop area, the southwestern single-double season mixed crop area, and the southern winter crop area with high soil fertility, and has a certain resistance to PVX and late blight, with excellent comprehensive traits, but this variety generally drops buds and does not bloom. For example, the potato variety Qingshu No. 9 has concentrated potato bearing, high rate of large potatoes, excellent high yield and stable yield, but pollen abortion, and cannot naturally bear fruit and produce hybrid seeds as a male parent. The above-mentioned excellent potato resources cannot be used as hybrid parents, which limits the genetic basis of potato hybrid breeding.

[0003] Grafting hybridization refers to the process of obtaining hereditary and grafted hybrids through grafting, also known as grafting mutagenesis. At present, people's understanding of "grafting hybridization" is gradually deepening. The concept of grafting hybridization was first proposed by Darwin, and there are many records of grafting hybridization in my country. There are two main theories about the variation of traits caused by grafting: (1) "Horizontal gene transfer" theory, that is, the exchange of genes and materials occurs between the rootstock and the scion, and the rootstock or scion mutates due to the absorption of each other's genetic material. There are reports abroad that some proteins (including "florin" that regulates flowering) and small RNA can be transported in the phloem of grafted plants. (2) "Epigenetic theory", that is, the special environment provided by the grafted plants for each other causes the gene expression of the rootstock or scion to undergo heritable changes without changing its own gene sequence. The latest research results from scientists from the Max Planck Institute in Germany show that grafted plants can exchange their respective genetic genes and create new species. This research result has been published in Nature and Science. They propose that grafting technology has broken through its traditional asexual reproduction significance and will open up a new method for cultivating allopolyploid plant hybrids. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for solving the problem of sterility of potato varieties as hybrid male parents, which overcomes the defects of the prior art and solves the long-standing problem of sterility of potato varieties as hybrid male parents.

[0005] One technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] A method for solving the abortion of potato varieties as male parents in hybridization, comprising the following steps:

[0007] (1) Cultivation and selection of rootstocks:

[0008] Select the original seeds of the virus-free seedling offspring of Jizhangshu No. 8, sow them, and apply sufficient base fertilizer; when the seedlings of Jizhangshu No. 8 grow to 3-5 expanded leaves, part of the seedlings are prepared as rootstocks for grafting, and the other part of the seedlings are conventionally managed and used as female parents for hybridization during the flowering period;

[0009] (2) Cultivation and selection of scions:

[0010] Select the original seeds of the virus-free seedling offspring of Jizhangshu No. 3, sow them in seedling trays, and when the seedlings just break through the soil and emerge 1 cm - 2 cm, they are prepared as scions for grafting;

[0011] (3) Grafting:

[0012] Before grafting, wipe the blade and hands with 75% alcohol for disinfection. After each group of grafting is completed, the blade and hands should be disinfected with alcohol. Wait for the alcohol to completely volatilize before proceeding to the next step;

[0013] (31) Preparation of rootstocks:

[0014] Remove the apical bud of Jizhangshu No. 8, retain 1-2 leaves below, and use the cleft grafting method between the stem internodes between the first fully expanded leaf and the second fully expanded leaf from the top, vertically downward, with the knife edge depth of 1.0 - 1.5 cm;

[0015] (32) Preparation of scions:

[0016] Cut the seedlings of Jizhangshu No. 3 from the base with a blade, remove all the leaves, and then cut the scion into a symmetrical wedge shape with a blade. The size of the wedge surface is the same as the size of the rootstock incision, and keep the wedge surface clean and tidy;

[0017] (33) Grafting:

[0018] Insert the scion into the rootstock incision, align the two incisions, and fix the rootstock and scion with a round-mouth horticultural grafting clip;

[0019] (4) Management after grafting:

[0020] Build a small arch shed above the grafted seedlings, disinfect the rootstock, scion and the surrounding environment with 800-fold solution of 50% carbendazim, cover the film tightly, and then cover it with a double-layer sunshade net. Spray water into the shed every day to keep the humidity in the shed above 90%, the daytime temperature at 25 - 30 °C, and the nighttime temperature at 15 - 18 °C;

[0021] 3 - 4 days after grafting, promptly remove the infected diseased seedlings. For those with relatively mild disease, remove the diseased leaves, and spray with 800 - fold solution of 50% carbendazim for prevention and control, once every 5 - 7 days, for 3 - 4 consecutive sprays. One week later, when the scion starts to grow, gradually remove the sunshade net and gradually ventilate. At this time, the humidity is maintained at 50 - 70%, the temperature during the day is kept at 25 - 28°C, and at night it is 14 - 15°C. 15 days later, when the scion potato has grown 2 - 3 leaves, remove the small arch shed, and conduct routine management to remove the suckers on the rootstock of Jizhangshu No. 8.

[0022] (5) Hybrid pollination:

[0023] (51) Emasculation of female parent: Select the flower buds of Jizhangshu No. 8 that are plump and 1 - 2 days before blooming. After separating the petals, remove the stamens.

[0024] (52) Collect pollen of male parent: After grafting, the scion Jizhangshu No. 3 blooms, and collect the pollen of Jizhangshu No. 3 for standby.

[0025] (53) Pollination, bagging, and tagging: Apply the collected pollen of the male parent to the stigma of emasculated Jizhangshu No. 8 potato, then bag it and hang a label, indicating the hybridization date, the variety names of the male and female parents, and repeat the pollination the next day.

[0026] (54) When the hybrid fruit matures, harvest the true - breeding seeds.

[0027] Preferably, the sowing depth in step (1) is 7 - 10 cm.

[0028] Preferably, in the seedling tray of step (2), the substrate is vermiculite and coconut coir, with a ratio of 1:1, and the soil covering thickness is 2 cm - 3 cm.

[0029] Preferably, Jizhangshu No. 8 is used as the female parent of the potato variety, and Jizhangshu No. 3 is used as the male parent of the potato.

[0030] The above - mentioned technical solution of the present invention has the following beneficial effects:

[0031] Through multiple experiments among numerous potato materials, the present invention finally determines to select Jizhangshu No. 8 as the rootstock because Jizhangshu No. 8 has a long flowering period and strong flower abundance. Through the material exchange of grafting, it induces the scion Jizhangshu No. 3 to bloom, solving the long - standing problem of no - flower and sterility of Jizhangshu No. 3 potato, and creating the possibility for other potato varieties with excellent traits but the same sterility problem (such as Qingshu No. 9) to produce hybrid offspring as parents. Detailed implementation mode

[0032] The following describes the specific embodiments of the present invention in detail for better understanding of the present invention.

[0033] All experimental methods used in the following examples are conventional methods unless otherwise specified. Materials, reagents, etc. used in the following examples can be obtained through commercial channels unless otherwise specified.

[0034] The present invention discloses a grafting method between different potato varieties, including the selection and cultivation of rootstocks, the cultivation of scions, grafting, post-grafting management, cross-pollination, and harvesting of true seeds. It solves the problems of flowerlessness and sterility of Jizhangshu No. 3, increases the flower quantity and prolongs the flowering period, and can increase the seed setting quantity of potatoes that could originally set seeds. Currently, there is no literature disclosure on the breeding problem of potato varieties being sterile as male parents in hybridization.

[0035] Example 1

[0036] Test method:

[0037] (1) Cultivation and selection of rootstocks:

[0038] Select the original seeds of the virus-free seedling offspring of Jizhangshu No. 8, with a sowing depth of 7 - 10 cm and sufficient base fertilizer applied; when the seedlings of Jizhangshu No. 8 grow to 3 - 5 expanded leaves, part of the seedlings are prepared as rootstocks for grafting, and the other part of the seedlings are managed conventionally and used as female parents for hybridization during the flowering period.

[0039] (2) Cultivation and selection of scions:

[0040] Select the original seeds of the virus-free seedling offspring of the potato variety Jizhangshu No. 3, sow them in seedling trays, with the substrate being vermiculite and coconut coir in a ratio of 1:1, and the soil covering thickness being 2 cm - 3 cm. When the seedlings just break through the soil and emerge about 1 cm - 2 cm, they are prepared as scions for grafting;

[0041] (3) Grafting:

[0042] Before grafting, wipe the blade and hands with 75% alcohol for disinfection. After each group of grafting is completed, the blade and hands need to be disinfected with alcohol. Only after the alcohol has completely evaporated can the next operation be carried out;

[0043] (31) Preparation of rootstocks:

[0044] Remove the apical bud of Jizhangshu No. 8, retain the following 1 - 2 leaves, and use the cleft grafting method between the stem internodes between the first fully expanded leaf and the second fully expanded leaf from the top, vertically downward, with the knife cut depth about 1.0 - 1.5 cm;

[0045] (32) Preparation of scions:

[0046] Use a blade to cut the seedlings of Jizhangshu No. 3 from the base, remove all the leaves, and then use the blade to cut the scion into a symmetrical wedge shape, with the size of the wedge surface being the same as that of the rootstock incision, and keep the wedge surface clean and tidy;

[0047] (33) Grafting:

[0048] Insert the scion into the cut of the rootstock, align the cuts of the two, and fix the rootstock and scion with a round-mouthed horticultural grafting clip;

[0049] (4) Management after grafting:

[0050] Build a small arch shed above the grafted seedlings, disinfect the rootstock, scion and the surrounding environment with 800-fold solution of 50% carbendazim, cover the film tightly, and then cover it with a double-layer sunshade net. Spray water into the shed every day to keep the humidity in the shed above 90%, keep the daytime temperature at 25 - 30°C, and the nighttime temperature at 15 - 18°C;

[0051] 3 - 4 days after grafting, promptly remove the infected seedlings. For those with less severe disease, remove the diseased leaves and spray with 800-fold solution of 50% carbendazim for prevention and control, once every 5 - 7 days, for 3 - 4 consecutive times; After one week, when the scion starts to grow, gradually remove the sunshade net and gradually ventilate. At this time, the humidity is maintained at 50 - 70%, the daytime temperature is kept at 25 - 28°C, and the nighttime temperature is 14 - 15°C; 15 days later, when the scion potato grows 2 - 3 leaves, remove the small arch shed and conduct routine management, paying attention to removing the suckers on the rootstock of Jizhangshu 8;

[0052] (5) Hybrid pollination:

[0053] (51) Emasculation of female parent: Select the flower buds of Jizhangshu 8 that are plump and 1 - 2 days before blooming. After separating the petals, remove the stamens;

[0054] (52) Collection of male parent pollen: After grafting, the scion Jizhangshu 3 blooms, and collect the pollen of Jizhangshu 3 for standby.

[0055] (53) Pollination, bagging, and tagging: Apply the collected male parent pollen on the stigma of the emasculated Jizhangshu 8 potato, bag it and hang a label, indicating the hybridization date, the variety names of the male and female parents, and repeat the pollination the next day;

[0056] (54) When the hybrid fruit matures, harvest the true seeds.

[0057] The test results are shown in Table 1:

[0058] Table 1 Influence of grafting on the fruit - setting rate of Jizhangshu 3 as the male parent in hybridization

[0059]

[0060] Furthermore, the female parent of the potato variety is Jizhangshu 8, and the male parent is Jizhangshu 3.

[0061] Jizhangshu 8, also known as "Dabaihua", is a fresh potato edible variety. The growth period is 99 days. It has an upright plant type, strong growth potential, and the plant height is about 68.7 cm. The stem and leaves are green, and the average number of main stems per plant is 3.5. The corolla is white, the flowering period is long, and the natural fruit set is medium. The tubers are oval, with light yellow skin, milky white flesh, shallow eyes, and smooth skin. The average number of tubers per plant is 5.2, and the average weight of a single tuber is 102 g. The commercial potato rate is 75.8%. In the production test, the average yield per 667 m 2 is 1388 kg.

[0062] In order to utilize the excellent traits of the above-mentioned potato variety Jizhangshu 3, the present invention uses the seedlings of Jizhangshu 3 as the scion, and the root system of Jizhangshu 8 with extremely strong flower lushness as the rootstock, which provides nutrients for the above-ground part and promotes the material exchange between Jizhangshu 3 and Jizhangshu 8, so as to promote the normal growth and development of reproductive organs.

[0063] Although the present invention has been disclosed above with examples, it is not intended to limit the present invention. Any person skilled in the art can make various different selections and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention is defined by the claims and their equivalent forms.

Claims

1. A method for solving the abortion of potato varieties as hybrid male parents, characterized in that, It includes the following steps: (1) Cultivation and selection of rootstock: Select the original seeds of the virus-free seedling offspring of Jizhangshu No. 8, sow them, and apply sufficient base fertilizer; when the seedlings of Jizhangshu No. 8 grow to 3 - 5 expanded leaves, a part of the seedlings are prepared as rootstock for grafting, and the other part of the seedlings are managed conventionally and used as female parents for hybridization during the flowering period; (2) Cultivation and selection of scion: Select the original seeds of the virus-free seedling offspring of Jizhangshu No. 3, sow them in seedling trays, and when the seedlings just break through the soil and emerge 1 cm - 2 cm, they are prepared as scions for grafting; (3) Grafting: Before grafting, wipe the blade and hands with 75% alcohol for disinfection. After each group of grafting is completed, disinfect the blade and hands with alcohol. Wait until the alcohol has completely evaporated before proceeding to the next step; (31) Preparation of rootstock: Remove the apical bud of Jizhangshu No. 8, retain 1 - 2 leaves below, and use the cleft grafting method between the stem internodes between the first and second fully expanded leaves from the top, vertically downward, with a knife cut depth of 1.0 - 1.5 cm; (32) Preparation of scion: Cut the seedlings of Jizhangshu No. 3 with a blade from the base, remove all the leaves, and then use the blade to cut the scion into a symmetrical wedge shape. The size of the wedge surface is the same as that of the rootstock incision, and keep the wedge surface clean and tidy; (33) Grafting: Insert the scion into the rootstock incision, align the incisions of the two, and fix the rootstock and scion with a round-mouth horticultural grafting clip; (4) Management after grafting: Build a small arch shed above the grafted seedlings, disinfect the rootstock, scion and the surrounding environment with 800 - fold solution of 50% carbendazim, cover the film tightly, and then cover it with a double-layer sunshade net. Spray water into the shed every day to keep the humidity in the shed above 90%, the daytime temperature at 25 - 30°C, and the nighttime temperature at 15 - 18°C; 3 - 4 days after grafting, promptly remove the infected diseased seedlings. For those with less severe disease, remove the diseased leaves and spray with 800 - fold solution of 50% carbendazim for prevention and control, once every 5 - 7 days, and spray 3 - 4 times continuously; After one week, when the scion starts to grow, gradually remove the sunshade net and gradually ventilate. At this time, the humidity is maintained at 50 - 70%, the daytime temperature is kept at 25 - 28°C, and the nighttime temperature is 14 - 15°C; 15 days later, when the scion potato grows 2 - 3 leaves, remove the small arch shed, manage it conventionally, and remove the suckers on the Jizhangshu No. 8 rootstock; (5) Hybrid pollination: (51) Emasculation of female parent: Select the flower buds of Jizhangshu No. 8 with large and plump flower buds, 1 - 2 days before flowering. After separating the petals, remove the stamens; (52) Collection of male parent pollen: After grafting, the scion Jizhangshu No. 3 blooms, and collect the pollen of the scion Jizhangshu No. 3 after grafting for standby; (53) Pollination, bagging, and tagging: Apply the collected male parent pollen on the stigma of the emasculated potato Jizhangshu No. 8, bag it and hang a label, indicating the hybridization date, the variety names of the male and female parents, and repeat the pollination the next day; (54) When the hybrid fruit is mature, harvest the true seeds.

2. The method for solving the abortion of potato varieties as male parents in hybridization according to claim 1, characterized in that, The sowing depth in step (1) is 7 - 10 cm.

3. The method for solving the abortion of potato varieties as male parents in hybridization according to claim 1, characterized in that, In the seedling trays in step (2), the substrate is vermiculite and coconut coir, with a ratio of 1:1, and the soil covering thickness is 2 cm - 3 cm.

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