Method for shortening the juvenile phase of guavas hybrid seedlings

Abstract

The application provides a method for shortening the childhood of Psidium guajava hybrid seedlings, and belongs to the technical field of fruit tree cultivation. In the application, different concentrations of nutrient solution are poured on the Psidium guajava seedlings to cultivate strong plants; after the main stem sprouts, 8-10 times of bud rubbing and pinching are carried out to promote the maturation of new shoots and the rapid expansion of the crown; and exogenous hormones and endogenous hormones are sprayed to promote the early flowering and fruiting of the plants. The method can shorten the childhood of the Psidium guajava hybrid seedlings from 18 months to 11 months, and thus solves the problems of long breeding cycle and low breeding efficiency of Psidium guajava caused by the long childhood of the Psidium guajava hybrid seedlings.

Description

Technical Field

[0001] The invention relates to the technical field of fruit tree cultivation, and in particular to a method for shortening the infancy period of guava hybrid seedlings. Background Art

[0002] Guava (Psidium guava), a plant of the genus Psidium in the Myricaceae family, is widely cultivated in tropical and subtropical regions. Previously, guava was a local specialty fruit, cultivated on a small scale and remaining a minor commodity. However, with the widespread adoption of imported guava varieties such as the pearl guava in suitable areas, guava has become a major local fruit. Currently, the main cultivated guava varieties are all imported, and the lack of independently bred varieties has become a bottleneck in the development of the guava industry.

[0003] Hybrid breeding is one of the primary methods for selecting improved fruit tree varieties, and is also the preferred method for selecting improved guava varieties. The juvenile period refers to the time from seed germination to the first flowering and fruiting, and the length of the juvenile period is a property of the plant. Woody fruit trees generally have a long juvenile period, and guava's juvenile period is generally over 1.5 years. This long juvenile period results in a longer time for guava hybrid seedlings to flower and fruit, resulting in a long guava hybrid breeding cycle and low efficiency in selecting improved varieties. Summary of the Invention

[0004] The object of the present invention is to provide a method for shortening the infancy period of guava hybrid seedlings.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a method for shortening the infancy period of guava hybrid seedlings. After the main trunk of the plant sprouts, bud removal and pinching are performed 8 to 10 times. After the seventh bud removal and pinching, the crown of the tree is sprayed with paclobutrazol. After 18 to 22 days, the crown of the tree is sprayed with a mixture of ethephon and guava flower bud extract, wherein the volume ratio of the ethephon to the guava flower bud extract is 1:780 to 820.

[0007] Preferably, the concentration of paclobutrazol is 0.12-0.18 g / L, and the spraying amount is 180-210 mL / plant.

[0008] Preferably, the concentration of the ethephon is 0.3-0.5 g / L.

[0009] Preferably, the spraying amount of the mixture of ethephon and guava flower bud extract is 190-220 mL / plant.

[0010] As preferred, the extraction method of the Psidium guajava flower bud extract solution comprises the following steps: grinding the flower buds of Psidium guajava of 15-20 days, grinding continuously with ethanol solution, and finally mixing with water for soaking to obtain the Psidium guajava flower bud extract solution.

[0011] As preferred, the ratio of the Psidium guajava flower bud to the ethanol solution is 50g:1-3mL, and the ratio of the Psidium guajava flower bud to water is 50g:950-1150mL.

[0012] As preferred, the specific operation of the bud wiping and the topping is as follows: after the main stem of the plant sprouts, 2-4 buds on the top and slanting outward are selected and reserved for cultivation into first-level branches, and the excessive buds are wiped; after the first-level branches grow to 4 pairs of leaves, the first-level branches are topped, and after the first-level branches sprout, 1-2 buds of each branch are reserved for cultivation into second-level branches, and the excessive buds are wiped; after the second-level branches grow to 4 pairs of leaves, the second-level branches are topped, and after the second-level branches sprout, 1-2 buds of each branch are reserved for cultivation into third-level branches, and the excessive buds are wiped; after the third-level branches grow to 4 pairs of leaves, the third-level branches are topped, and after the topping, only 1 bud is reserved for cultivation into the next-level branches; the topping and the bud wiping are performed for 8-10 times, and the new shoots appear until flower buds appear.

[0013] As preferred, before the bud wiping and the topping, the following steps are further included:

[0014] (1) the seeds of Psidium guajava are mixed with fine sand and then sowed in the substrate;

[0015] (2) the nutrient solution mother liquor is diluted by 9-11 times to obtain nutrient solution 1; after the seeds sprout uniformly, the nutrient solution 1 is poured, and the pouring is performed once every 7-10 days, and the pouring amount is 4.5-5.5L / m 2 ;

[0016] (3) the seedlings are transplanted after the first pair of true leaves completely unfold;

[0017] (4) the nutrient solution mother liquor is diluted by 4-6 times to obtain nutrient solution 2; after the seedlings are transplanted for 7-9 days, the nutrient solution 2 is poured, and the pouring is performed once every 7-14 days, and the pouring amount is 180-220mL / plant;

[0018] (5) when the height of the Psidium guajava seedlings grows to 20-23cm, the seedlings are planted;

[0019] (6) the nutrient solution mother liquor is diluted by 1.5-2.5 times to obtain nutrient solution 3; after the seedlings are planted for one week, the nutrient solution 3 is poured, and the pouring is performed once every 8-12 days, and the pouring amount is 900-1100mL / plant.

[0020] As preferred, in step (1), the weight ratio of the fine sand to the seeds is 4-6:1, the substrate is a mixture of peat soil and vermiculite, the volume ratio of the peat soil to the vermiculite is 2-4:1, and after sowing, the substrate with a thickness of 0.1-0.3cm is covered.

[0021] Preferably, the nutrient solution mother liquor is composed of components of the following concentrations: KH2PO4 3.67 mmol / L, (NH4)2SO4 4.54 mmol / L, Ca(NO3)2 4.88 mmol / L, K2SO4 1.72 mmol / L; MgSO4·7H2O 0.57 mmol / L; Fe.Na.EDTA 102.66 μmol / L, ZnSO4.7H2O 11.62 μmol / L, MnSO4·H2O 22.01 μmol / L, Na2MoO4 19.42 μmol / L, H3BO3 2.62 μmol / L, NiCl2·6H2O 1.33 μmol / L.

[0022] By adopting the above technical solution, the present invention has the following beneficial effects:

[0023] In the present invention, during the guava seedling stage, nutrient solutions of varying concentrations are applied to cultivate robust plants. After the main trunk sprouts, bud removal and topping are performed 8 to 10 times to promote the maturation of new shoots and rapid expansion of the crown. Exogenous and endogenous hormones are sprayed in combination to promote early flowering and fruiting. The method of the present invention can shorten the infancy period of guava hybrid seedlings from 18 months to 11 months, thereby resolving the problem of long guava breeding cycles and low breeding efficiency caused by the long infancy period of guava hybrid seedlings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 For example, flower buds appeared for the first time on a hybrid pomegranate seedling (August 23, 2021).

[0025] Figure 2 For collecting and grinding flower buds.

[0026] Figure 3 The flower bud extract is allowed to stand and the supernatant is separated. DETAILED DESCRIPTION

[0027] The invention provides a method for shortening the infancy period of guava hybrid seedlings. After the main trunk of the plant sprouts, the buds are removed and the tops are pinched, and the crowns are sprayed with paclobutrazol; and the crowns are sprayed with a mixture of ethephon and guava flower bud extract.

[0028] The present invention preferably further comprises the steps of seed sowing and culturing before the main trunk of the guava plant sprouts; and further preferably comprises the following steps:

[0029] (1) Soak guava seeds in chlorothalonil solution;

[0030] (2) Mix guava seeds with fine sand and sow them in the substrate;

[0031] (3) diluting the nutrient solution mother liquor by 9-11 times to obtain nutrient solution 1; after the seeds germinate evenly, watering the nutrient solution 1, watering once every 7-10 days, and watering 4.5-5.5 L / m each time 2 ;

[0032] (4) moving seedlings after the first pair of true leaves of the seedlings completely unfold;

[0033] (5) diluting the nutrient solution mother liquor by 4-6 times to obtain nutrient solution 2; after moving seedlings for 7-9 days, watering the nutrient solution 2, watering once every 7-14 days, and watering 180-220 mL / plant each time;

[0034] (6) planting when the height of the guavoside seedlings is 20-23 cm;

[0035] (7) diluting the nutrient solution mother liquor by 1.5-2.5 times to obtain nutrient solution 3; watering the nutrient solution 3 after planting for one week, watering once every 8-12 days, and watering 900-1100 mL / plant each time.

[0036] In the present application, the seeds are washed with clean water, soaked in a chlorothalonil solution, and then washed with clean water again. The chlorothalonil solution is prepared by diluting 75% chlorothalonil by 900-1100 times, preferably by 950-1050 times, and more preferably by 1000 times. The soaking time of the seeds is preferably 0.5-1.5 hours, and more preferably 1 hour.

[0037] In the present application, fine sand is mixed with the soaked guavoside seeds and then sown in the substrate. The weight ratio of the fine sand to the seeds is preferably 4-6:1, further preferably 4.5-5.5:1, and more preferably 5:1. The substrate is a mixture of peat soil and vermiculite, and the volume ratio of the peat soil to the vermiculite is preferably 2-4:1, further preferably 2.5-3.5:1, and more preferably 3:1. After sowing, the present application preferably covers the seeds with a layer of substrate with a thickness of 0.1-0.3 cm, and the thickness of the covering substrate is further preferably 0.2 cm. The present application preferably sows 1-2 seeds per hole, and more preferably sows 1 seed per hole.

[0038] In the present application, the female parent of the guavoside seeds is preferably Hongxiang No. 1 (Zhang Chaokun, Kang Shicheng, Huang Wanli, Li Hui. Characteristics and Cultivation Techniques of ‘Hongxiang No. 1’ Guavoside [J]. Southeast Gardening, 2021, 9(03): 45-48.), which is selected and bred by Zhangzhou Agricultural Science Institute. The male parent is preferably Emperor, which is purchased from Changtai County Lvfu Family Farm.

[0039] In the present application, the nutrient solution 1 is used to water the seeds after they germinate evenly. The nutrient solution 1 is obtained by diluting the nutrient solution mother liquor by 9-11 times, preferably by 10 times. In the present application, the nutrient solution 1 is watered once every 7-10 days, and preferably once every 8-9 days. The amount of the nutrient solution 1 watered each time is 4.5-5.5 L / m.2 , more preferably 4.8 to 5.3 L / m 2 , more preferably 5 L / m 2 , until the first pair of true leaves of the seedlings are fully expanded.

[0040] The present invention transplants the seedlings after the first pair of true leaves of the seedlings are fully expanded, and preferably transplants the guava seedlings into plastic nutrient cups; the specifications of the plastic nutrient cups are further preferably 13 cm*12 cm, and the culture medium is the same as the medium in step 2); the present invention waters the nutrient solution 2 7 to 9 days after transplanting the seedlings, preferably, waters the nutrient solution 2 8 days after transplanting the seedlings; the amount of nutrient solution 2 watered each time is 180 to 220 mL / plant, more preferably 190 to 210 L / m 2 , more preferably 200 mL / plant; the nutrient solution 2 is obtained by diluting the nutrient solution mother solution 4 to 6 times, preferably 5 times.

[0041] According to the present invention, the guava seedlings are transplanted when they grow to 20 to 23 cm, preferably when they grow to 21 to 22 cm; during transplanting, the trunk of the guava seedling is shortened to 14 to 16 cm, more preferably to 15 cm; according to the present invention, the shortened guava seedlings are preferably transplanted into a planting bag, the specification of the planting bag is more preferably 30 cm×35 cm, and the substrate is the same as the substrate in step 2).

[0042] The present invention waters the nutrient solution 3 7 to 9 days after planting, preferably 8 days after planting; the nutrient solution 3 is obtained by diluting the nutrient solution mother liquor by 1.5 to 2.5 times, preferably 2 times; in the present invention, the frequency of watering the nutrient solution 3 is 8 to 12 days / time, more preferably 10 days / time, and each time the amount of watering is 900 to 1100 mL / plant, more preferably 1000 mL / plant.

[0043] In the present invention, the nutrient solution mother liquor is composed of components with the following concentrations: KH2PO43.67mmol / L, (NH4)2SO44.54mmol / L, Ca(NO3)24.88mmol / L, K2SO41.72mmol / L; MgSO4·7H2O0.57mmol / L; Fe.Na.EDTA102.66μmol / L, ZnSO4.7H2O11.62μmol / L, MnSO4·H2O22.01μmol / L, Na2MoO419.42μmol / L, H3BO32.62μmol / L, NiCl2·6H2O1.33μmol / L.

[0044] When guava seeds first sprout, their accumulated nutrients have been depleted. At this point, a 9- to 11-fold diluted nutrient solution can effectively and safely provide nutrition to the seedlings. Guava seedlings have weak root systems and poor absorption capacity for nutrient solution, so a lower concentration of nutrient solution is recommended. A 4- to 6-fold diluted nutrient solution can effectively promote seedling growth and development. As the plant grows, its nutrient demand increases, requiring increased nutrient solution concentration and dosage. After transplanting, a 1.5- to 2.5-fold diluted nutrient solution should be used. Using different nutrient solution concentrations at different stages of guava growth aligns with the plant's nutritional needs.

[0045] The method comprises the following steps: after the main trunk of the guava plant sprouts, removing the buds and pinching the tops; spraying the crowns with paclobutrazol; and spraying the crowns with a mixture of ethephon and guava flower bud extract.

[0046] In the present invention, the specific operation of the bud removal and pinching is as follows: after the main trunk of the plant sprouts, select 2-4 buds obliquely outward from the top and cultivate them as first-level branches, and remove the excess buds in time. After the first-level branches grow to 4 pairs of leaves, pinch them to accelerate the maturation of the first-level branches and branches, and promote the germination of the axillary buds at the top. After the first-level branches sprout, 1-2 buds are left on each branch to be cultivated into second-level branches, and the excess buds are removed in time. Similarly, after the second-level branches grow to 4 pairs of leaves, pinch them to accelerate the maturation of the second-level branches and branches, and promote the germination of the axillary buds at the top. After the second-level branches sprout, 1-2 buds are left on each branch to be cultivated into third-level branches, and the excess buds are removed in time. After two pinching and bud removal, 8-10 third-level branches are cultivated. After the third-level and above branches grow to 4 pairs of leaves, pinch them, and only 1 bud is left after pinching to be cultivated into the next-level branches. So pinching and bud removal are continued until flower buds appear on the new shoots.

[0047] In this method, the number of times of removing buds and pinching is 8 to 10 times, preferably 9 times.

[0048] In the present invention, the crown is sprayed with paclobutrazol after the 7th pinching; the concentration of paclobutrazol is 0.12-0.18 g / L, more preferably 0.14-0.16 g / L, more preferably 0.15 g / L; the spraying amount of paclobutrazol is preferably 180-210 mL / plant, more preferably 200 mL / plant. When spraying, both the front and back sides of the leaves should be sprayed, and it is better to spray until water drips from the leaves.

[0049] In the present invention, the ethephon and guava flower bud extract mixture is sprayed on the tree crown 18 to 22 days after spraying paclobutrazol, more preferably 19 to 21 days after spraying paclobutrazol, and more preferably 20 days after spraying. In the present invention, the concentration of the ethephon is 0.3 to 0.5 g / L, more preferably 0.35 to 0.45 g / L, and more preferably 0.4 g / L; in the ethephon and guava flower bud extract mixture, the volume ratio of the ethephon to the guava flower bud extract is preferably 1:780 to 820, more preferably 1:790 to 810, and more preferably 1:800; the spraying amount of the ethephon and guava flower bud extract mixture is 190 to 220 mL / plant, preferably 200 mL / plant; when spraying, both the front and back sides of the leaves should be sprayed, and it is best to spray until the leaves drip.

[0050] In the present invention, the extraction method of the guava flower bud extract comprises the following steps: grinding the guava flower buds, adding an ethanol solution and continuing to grind, finally mixing with water and soaking, and filtering to obtain the guava flower bud extract.

[0051] In the present invention, the guava flower buds are preferably flower buds that have grown for 15 to 20 days, more preferably 16 to 18 days, and even more preferably 17 days.

[0052] In the present invention, the ratio of the guava flower buds to the ethanol solution is 50g:1-3mL, more preferably 50g:1.5-2.5mL, more preferably 50g:2mL; the volume fraction of the ethanol solution is 70-80%, more preferably 75%.

[0053] In the present invention, the ratio of the guava flower buds to water is 50g:950-1150mL, more preferably 1000-1100mL, and further preferably 1050mL.

[0054] In the present invention, the guava flower bud extract is obtained by adding water and soaking for 2 to 4 hours, more preferably 3 hours, and filtering with gauze after soaking.

[0055] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0056] Example 1

[0057] Sowing and seedling cultivation: Select mature artificial hybrid guava fruits (whose parents are ♀Hongxiang No. 1, ♂Emperor), take out the seeds, rinse them with clean water, and then soak them in 900 times solution of 75% chlorothalonil for 0.5h, then rinse them with clean water again, take clean fine sand and mix them with the seeds. The weight ratio of fine sand to seeds is 4:1, and then sow them in the seedling tray filled with substrate, sow 1 seed per hole, and then cover with 0.1cm thick substrate, and finally water them thoroughly. The substrate ratio is peat soil: vermiculite = 2:1, and the seedling tray size is 30cm×70cm. After sowing the seeds, water them once a day to keep the substrate moist. After the seeds germinate neatly, start watering with nutrient solution 1 diluted 11 times with nutrient mother solution, and then water them once every 7 days, with 4.5L / m each time. 2 , promote seedling growth.

[0058] Transplanting and Cultivating Guava Seedlings: Transplant seedlings after their first pair of true leaves fully expand. Transplant the seedlings into plastic nutrient cups. Water thoroughly after transplanting and water daily to keep the substrate moist. After 7 days, begin watering with nutrient solution 2 diluted 6 times the mother nutrient solution. Water every 7 days, at 180 mL per plant, to promote seedling growth. The nutrient cups should be 13 cm x 12 cm, and the substrate should be the same as above.

[0059] Planting and plant cultivation: Use the substrate cultivation method to cultivate plants. When the guava seedlings grow to a height of 21 cm, plant them. Before planting, shorten the main trunk of the seedlings to 14 cm, remove the nutrient cup, and plant the seedlings in the planting bag. Water them thoroughly after planting, and water them once a day to keep the substrate moist. After 7 days, start watering with nutrient solution 3 diluted 2.5 times with nutrient mother solution, and water them once every 8 days, each time with 900 mL / plant, to promote plant growth.

[0060] Bud removal and pinching: After the main trunk of the plant sprouts, select the two buds at the top that are tilted outward to be cultivated as first-level branches, and remove the excess buds in time. Pinch the first-level branches after they grow to 4 pairs of leaves to accelerate the maturation of the first-level branch leaves and promote the germination of the axillary buds at the top. After the first-level branches sprout, keep two buds on each branch to cultivate into second-level branches, and remove the excess buds in time. Similarly, pinch the second-level branches after they grow to 4 pairs of leaves to accelerate the maturation of the second-level branch leaves and promote the germination of the axillary buds at the top. After the second-level branches sprout, keep two buds on each branch to cultivate into third-level branches, and remove the excess buds in time. After two pinching and bud removal, cultivate 8-10 third-level branches. Pinch the branches above the third level when they grow to 4 pairs of leaves. After pinching, keep only one bud to cultivate into the next-level branch. Repeat pinching and bud removal until flower buds appear on the new shoots.

[0061] Preparation of guava flower bud extract: Preparation method of flower bud extract: Take 50g of guava flower buds 15 days old, grind them into powder with a mortar, add 1mL of 75% ethanol and continue grinding during the grinding process, add 950mL of water after grinding, soak for 3h, filter with gauze, and the filtrate is the guava flower bud extract.

[0062] Use of growth regulators: Do it twice. After the 7th pinching, first spray the crown with 0.12g / L paclobutrazol at a rate of 180mL / plant. After 18 days, mix 0.3g / L ethephon and guava flower bud extract at a volume ratio of 1:780, mix well and spray the crown with a spray rate of 190mL / plant.

[0063] Example 2

[0064] Sowing and seedling cultivation: Select mature artificial hybrid guava fruits (whose parents are ♀Hongxiang No. 1, ♂Emperor), take out the seeds, rinse them with clean water, and then soak them in 1000 times solution of 75% Benomyl for 1 hour, then rinse them with clean water again, take clean fine sand and mix them with the seeds. The weight ratio of fine sand to seeds is 5:1, and then sow them in the seedling tray filled with substrate, sow 1 seed per hole, and then cover with 0.2cm thick substrate, and finally water them thoroughly. The substrate ratio is peat soil: vermiculite = 3:1, and the seedling tray size is 30cm×70cm. After sowing the seeds, water them once a day to keep the substrate moist. After the seeds germinate neatly, start watering with nutrient solution 1 diluted 10 times with nutrient solution mother liquor, and then water them once every 8 days, with 5L / m each time. 2 , promote seedling growth.

[0065] Transplanting and Cultivating Guava Seedlings: Transplant seedlings after their first pair of true leaves fully expand. Transplant the seedlings into plastic nutrient cups. Water thoroughly after transplanting and water daily to keep the substrate moist. After 8 days, begin watering with nutrient solution 2 diluted 5-fold from the mother nutrient solution. Water every 10 days, at 200 mL per plant, to promote seedling growth. The nutrient cups are 13 cm x 12 cm in size, and the substrate is the same as above.

[0066] Planting and plant cultivation: Use the substrate cultivation method to cultivate plants. Plant when the seedlings grow to 22cm in height. Before planting, shorten the main trunk of the seedlings to 15cm, remove the nutrient cup, and plant the seedlings in the planting bag. Water thoroughly after planting, and water once a day to keep the substrate moist. After 8 days, start watering with nutrient solution 3 diluted twice with nutrient solution mother liquor, and water once every 10 days thereafter, watering 1000mL / plant each time to promote plant growth.

[0067] Bud removal and pinching: After the main trunk of the plant sprouts, select the three buds that are tilted outward at the top to be cultivated as first-level branches, and remove the excess buds in time. Pinch the first-level branches after they grow to 4 pairs of leaves to accelerate the maturation of the first-level branch leaves and promote the germination of the axillary buds at the top. After the first-level branches sprout, leave one bud on each branch to be cultivated as second-level branches, and remove the excess buds in time. Similarly, pinch the second-level branches after they grow to 4 pairs of leaves to accelerate the maturation of the second-level branch leaves and promote the germination of the axillary buds at the top. After the second-level branches sprout, leave two buds on each branch to be cultivated as third-level branches, and remove the excess buds in time. After two pinching and bud removal, cultivate 8-10 third-level branches. Pinch the branches above the third level when they grow to 4 pairs of leaves. After pinching, leave only one bud to be cultivated as the next-level branch. Repeat pinching and bud removal until flower buds appear on the new shoots.

[0068] Preparation method of guava flower bud extract: take 50g of guava flower buds 18 days old, grind them into powder with a mortar, add 2mL of 75% ethanol and continue grinding during the grinding process, add 1000mL of water after grinding, soak for 3h, filter with gauze, and the filtrate is the guava flower bud extract.

[0069] Use of growth regulators: Do it twice. After the 7th pinching, first spray the crown with 0.15g / L paclobutrazol at a rate of 200mL / plant. After 20 days, mix 0.4g / L ethephon and guava flower bud extract at a volume ratio of 1:800, mix well and spray the crown with 200mL / plant.

[0070] Example 3

[0071] Sowing and seedling cultivation: Select mature artificial hybrid guava fruits (whose parents are ♀Hongxiang No. 1, ♂Emperor), take out the seeds, rinse them with clean water, and then soak them in 1100 times solution of 75% Benomyl for 1.5 hours, then rinse them with clean water again, take clean fine sand and mix them with the seeds. The weight ratio of fine sand to seeds is 6:1, and then sow them in the seedling tray filled with substrate, sow 1 seed per hole, and then cover with 0.3cm thick substrate, and finally water them thoroughly. The substrate ratio is peat soil: vermiculite = 4:1, and the seedling tray size is 30cm×70cm. After sowing the seeds, water them once a day to keep the substrate moist. After the seeds germinate neatly, start watering with nutrient solution 1 diluted 11 times with nutrient mother solution, and water them once every 10 days thereafter, with 5.5L / m 2 , promote seedling growth.

[0072] Transplanting and Cultivating Guava Seedlings: Transplant seedlings after their first pair of true leaves fully expand. Transplant seedlings into plastic nutrient cups. Water thoroughly after transplanting and water daily to keep the substrate moist. After 9 days, begin watering with nutrient solution 2 diluted fourfold with the nutrient solution. Water every 14 days, at 220 mL per plant, to promote seedling growth. The nutrient cups should be 13 cm x 12 cm, and the substrate should be the same as above.

[0073] Planting and plant cultivation: the plant is cultivated by using the method of substrate cultivation, when the height of the seedling is 23 cm, the seedling is planted, the main stem of the seedling is cut to 16 cm short before planting, the nutrient cup is removed, the seedling is planted into the Meiweixi bag, after planting, the water is poured thoroughly, and then water is poured once a day to keep the substrate moist, after 9 days, the nutrient solution 3 diluted 1.5 times by the nutrient mother liquor is poured, and then the nutrient solution is poured once every 10 days, and each time 1100 mL / plant is poured to promote the growth of the plant.

[0074] Bud wiping and pinching: after the main stem of the plant sprouts, 4 buds on the top and slanting outward are selected and left to cultivate first branches, and the remaining buds are timely wiped. After the first branches grow to 4 pairs of leaves, the first branches are pinched, the leaves of the first branches are matured, the apical axillary buds are promoted to germinate, after the first branches sprout, 1 bud of each branch is left to cultivate second branches, and the remaining buds are timely wiped. Similarly, after the second branches grow to 4 pairs of leaves, the second branches are pinched to mature the leaves of the second branches and promote the apical axillary buds to germinate, after the second branches sprout, 1 bud of each branch is left to cultivate third branches, and the remaining buds are timely wiped. After two times of pinching and bud wiping, 8-10 third branches are cultivated, the third branches above the third branches are pinched when the third branches grow to 4 pairs of leaves, and only 1 bud is left to cultivate the next level of branches after pinching, and the pinching and bud wiping are continuously performed until flower buds appear on new shoots.

[0075] Preparation method of guavoside extract: 50 g of flower buds of Psidium guajava at 20 d are ground into powder with a mortar, 3 mL of 75% ethanol is added during the grinding process, 1150 mL of water is added after the grinding, and then soaked for 4 h, filtered with gauze, and the filtrate is guavoside extract.

[0076] Use of growth regulators: the use is performed twice, 0.18 g / L of paclobutrazol is sprayed on the crown of the plant after the 7th pinching, the spraying amount is 210 mL / plant, 22 d later, 0.5 g / L of ethylene and guavoside extract are mixed according to a volume ratio of 1:820, the mixture is uniformly sprayed on the crown of the plant, and the spraying amount is 220 mL / plant.

[0077] Experimental example

[0078] Implementation time: from September 6, 2021 to March 14, 2023.

[0079] Test site: Psidium guajava planting base (plastic film greenhouse) of Zhangzhou Agricultural Science Institute.

[0080] Test material: mature artificial hybrid Psidium guajava fruits are selected, and the parent varieties are as follows: ♀ Hongxiang No. 1 and ♂ emperor.

[0081] Test design: the cultivation method of the application is taken as the test group, and the normal cultivation and grafting cultivation methods are taken as the control groups.

[0082] Test reagent:

[0083] Paclobutrazol: Shanghai Yuelian Chemical Co., Ltd.

[0084] Active ingredient content: 15%

[0085] Dosage form: wettable powder;

[0086] Ethephon: Pengpu Chemical Plant of Shanghai Huayi Group Huayuan Chemical Co., Ltd.

[0087] Active ingredient content: 40%

[0088] Dosage form: aqueous solution.

[0089] The experimental design is shown in Table 1:

[0090] Table 1 Experimental design

[0091]

[0092] The experimental group was carried out according to the following steps:

[0093] Sowing and seedling cultivation: On September 6, 2021, mature artificial hybrid guava fruits (whose parents are ♀Hongxiang No. 1, ♂Emperor) were selected, the seeds were taken out, rinsed with clean water, and then soaked in 1000 times 75% chlorothalonil solution for 1 hour, then rinsed with clean water again, and clean fine sand was mixed with the seeds. The weight ratio of fine sand to seeds was 5:1. Then they were sown in a seedling tray filled with substrate, covered with a 0.2cm thick substrate, and finally watered thoroughly. The substrate ratio is peat soil: vermiculite = 3:1, and the seedling tray specification is 30cm×70cm. After sowing the seeds, water them once a day to keep the substrate moist. After the seeds germinate neatly, start watering with nutrient solution 1 diluted 10 times with the nutrient solution mother liquor, and water once every 7 days thereafter, with 5L / m 2 , promote seedling growth.

[0094] Transplanting and guava seedling cultivation: On October 15, 2021, transplant the seedlings after the first pair of true leaves are fully expanded, and transplant the seedlings into plastic nutrient cups. Water them thoroughly after transplanting, and then water them once a day to keep the substrate moist. After one week, start watering with nutrient solution 2 diluted 5 times by the mother solution of nutrient solution, and then water once every 10 days, each time with 200ml L / m 2 , to promote the growth of seedlings. The specification of the nutrient cup is 13cm*12cm, and the substrate is the same as above.

[0095] Planting and plant cultivation: Use the substrate cultivation method to cultivate plants. On March 12, 2022, when the seedlings grow to a height of more than 20 cm, transplant them. Before transplanting, leave a 15 cm short cut on the main trunk of the seedlings, remove the nutrient cup, and transplant the seedlings into woven bags. Water thoroughly after transplanting, and water once a day to keep the substrate moist. After 1 week, start watering with nutrient solution 3 diluted twice with nutrient solution mother liquor, and water once every 10 days thereafter, watering 1000 mL / plant each time to promote plant growth.

[0096] Bud removal and pinching: After the main trunk of the plant sprouts, select 2-4 buds that are tilted outward at the top to be cultivated as first-level branches, and remove the excess buds in time. Pinch the first-level branches after they grow to 4 pairs of leaves to accelerate the maturation of the first-level branch leaves and promote the germination of the axillary buds at the top. After the first-level branches sprout, keep 1-2 buds on each branch to be cultivated as second-level branches, and remove the excess buds in time. Similarly, pinch the second-level branches after they grow to 4 pairs of leaves to accelerate the maturation of the second-level branch leaves and promote the germination of the axillary buds at the top. After the second-level branches sprout, keep 1-2 buds on each branch to be cultivated as third-level branches, and remove the excess buds in time. After two pinching and bud removal, cultivate 8-10 third-level branches. Pinch the branches above the third level when they grow to 4 pairs of leaves. After pinching, only keep 1 bud to be cultivated as the next-level branch. Repeat pinching and bud removal until flower buds appear on the new shoots.

[0097] Preparation of guava flower bud extract: 50 g of guava flower buds, aged 15-20 days, are ground into powder in a mortar and pestle. 2 mL of 75% ethanol is added during the grinding process. After grinding, 1000 mL of water is added, and the mixture is allowed to soak for 3 hours. The filtrate is filtered through gauze to obtain the guava flower bud extract. The concentrations of the active ingredients in the guava flower bud extract are: abscisic acid (ABA): 321 ng / gFW, auxin (IAA): 5.21 ng / gFW, gibberellins (GAs): 0.57 ng / gFW, and cytokinin (CTK): 0.495 ng / gFW.

[0098] Use of growth regulators: Do it twice. After the 7th pinching, spray the crown with 0.15g / L paclobutrazol first, the spraying amount is 200mL. After 20 days, mix 0.4g / L ethephon and guava flower bud extract in a volume ratio of 1:800, mix well and spray the crown with a spraying amount of 200mL.

[0099] The control group was treated according to the following steps:

[0100] Steps 1 to 3 were the same as those of the experimental group.

[0101] Step 4: Shaping and Pruning: After the main trunk sprouts, select 2-4 buds at the top that face outward and cultivate them as first-level branches. When the first-level branches mature, leave them 30-40 cm short to promote the germination of axillary buds at the top. After the first-level branches sprout, leave 1-2 buds on each branch to cultivate them into second-level branches. Remove any excess buds in time. After the second-level branches mature, leave them 30-40 cm short to promote the germination of axillary buds at the top. After the second-level branches sprout, leave 1-2 buds on each branch to cultivate them into third-level branches. Remove any excess buds in time. Repeat this process for branches above the third level until flower buds appear on the new shoots.

[0102] The number of flower buds in the experimental group and the control group were counted, and the rate of flowering branches was calculated.

[0103] Flowering branch rate = number of flowering branches / total number of branches × 100%

[0104] The test results are shown in Table 2:

[0105] Table 2 Effects of different treatments on flowering of guava hybrid seedlings

[0106]

[0107] Note: The number of flower buds refers to the number of flower buds within 30 days after the first budding

[0108] As can be seen from Table 2, using the cultivation method of the present invention, the time from sowing to the appearance of flower buds of guava hybrid seedlings was only 11 months, the bud appearance time was August 23, 2022, and the number of flower buds was also large. Compared with the control group, the cultivation method of the present invention can shorten the childhood period of guava hybrid seedlings from 18 months to 11 months, and bloom and bear fruit 7 months earlier, thereby accelerating the identification of the traits of the first generation of guava hybrids, thereby improving breeding efficiency.

[0109] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for shortening the infancy period of guava hybrid seedlings, characterized in that: The following steps are involved: (1) Mix guava seeds with fine sand and sow them in the substrate; (2) Dilute the nutrient solution mother solution 9 to 11 times to obtain nutrient solution 1; water the seeds with nutrient solution 1 after they have germinated neatly, once every 7 to 10 days, at 4.5 to 5.5 L / m 2 ; (3) Transplant the seedlings after the first pair of true leaves are fully expanded; (4) Dilute the nutrient solution mother solution 4 to 6 times to obtain nutrient solution 2; irrigate the seedlings with nutrient solution 2 7 to 9 days after transplanting, and irrigate once every 7 to 14 days, with 180 to 200 mL per plant each time; (5) When the guava seedlings grow to a height of 20-23 cm, they are transplanted; (6) Dilute the nutrient solution mother solution 1.5 to 2.5 times to obtain nutrient solution 3; water the nutrient solution 3 7 to 9 days after planting, and water once every 8 to 12 days, with 900 to 1100 mL per plant each time; (7) After the main trunk of the plant sprouts, remove the buds and pinch the tops 8 to 10 times. After the 7th removal of the buds and pinching, spray the crown with paclobutrazol; 18 to 22 days later, spray the crown with a mixture of ethephon and guava flower bud extract, with the volume ratio of ethephon to guava flower bud extract being 1:780 to 820; The nutrient solution mother solution is composed of the following components: KH2PO4 3.67mmol / L, (NH4)2SO4 4.54mol / L, Ca(NO3)2 4.88mmo1 / L, K2SO4 1.72mmol / L; MgSO4·7H2O 0.57mmol / L; Fe.Na.EDTA 102.66μmol / L, ZnSO4·7H2O 11.62μmol / L, MnSO4·H2O 22.01μmol / L, NaMoO4 19.42μmo1 / L, H3BO3 2.62μmo1 / L, NiCl2·6H2O 1.33mol / L; The guava flower bud extract comprises the following steps: grinding guava flower buds that are 15 to 20 days old, adding ethanol solution and continuing to grind, and finally mixing with water and soaking to obtain the guava flower bud extract.

2. The method according to claim 1, characterized in that The concentration of paclobutrazol is 0.12-0.18 g / L, and the spraying amount is 180-210 mL / plant.

3. The method according to claim 1, characterized in that The concentration of the ethephon is 0.3-0.5 g / L.

4. The method according to claim 1, wherein The spraying amount of the mixture of ethephon and guava flower bud extract is 190-220 mL / plant.

5. The method according to claim 1, wherein the ratio of the guava flower bud to the ethanol solution is 50 g: 1-3 mL, and the ratio of the guava flower bud to water is 50 g: 950-1150 mL.

6. The method according to claim 1, characterized in that The specific operations of bud removal and topping are as follows: after the main trunk of the plant sprouts, 2 to 4 buds at the top obliquely outward are selected and cultivated as first-level branches, and the excess buds are removed; after the first-level branches grow to 4 pairs of leaves, they are topped, and after the first-level branches sprout, 1 to 2 buds are left on each branch to be cultivated into second-level branches, and the excess buds are removed; after the second-level branches grow to 4 pairs of leaves, they are topped, and after the second-level branches sprout, 1 to 2 buds are left on each branch to be cultivated into third-level branches, and the excess buds are removed; after the third-level and above branches grow to 4 pairs of leaves, they are topped, and only 1 bud is left after topping to be cultivated into the next-level branches; and this topping and bud removal are repeated 8 to 10 times until flower buds appear on the new shoots.

7. The method according to claim 1, characterized in that In step (1), the weight ratio of the fine sand to the seeds is 4-6:1, the matrix is ​​a mixture of peat soil and vermiculite, and the volume ratio of the peat soil to the vermiculite is 2-4:1; after sowing, the matrix is ​​covered with a thickness of 0.1-0.3 cm.

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