CN116034865A

CN116034865A - Walnut half-sibling family breeding method

Info

Publication number: CN116034865A
Application number: CN202211699789.5A
Authority: CN
Inventors: 郭兴贵; 陈钰; 赵潇; 张瑞生; 杨静静
Original assignee: Chengxian Xingfeng Agriculture And Forestry Science And Technology Co ltd
Current assignee: Chengxian Xingfeng Agriculture And Forestry Science And Technology Co ltd
Priority date: 2022-12-28
Filing date: 2022-12-28
Publication date: 2023-05-02

Abstract

The invention relates to the technical field of walnuts, and discloses a breeding method of a half-sibling family of walnuts, which comprises the following steps: step one: parent selection: the ripple is soaking with the walnut; the ripple is multiplied by the cotton-sandwiched walnut; the ripple is soaking with little walnut; the ripple is soaking with the early fruit walnut; an interspecific hybrid combination; bubble x yanglin a; yun Lin A7 Xripple bubble; ripple x Xinzao 10; xinzao No. 10 Xripple bubble; bubble x Qinzao 13; xinzao 13 Xripple bubbles; large white shell x philic No. 10; xinzao No. 10 x white shell; white crust x Yun Lin A7; yun Lin A No. 7 x white crust; white crust x new No. 13; xinzao 13 # x large white shell; three X Xinzao No. 12; new morning No. 12 x three; three x new morning No. 13. The traditional breeding method is combined with the tissue culture technology, the germination rate of hybrid young embryo reaches 96%, the rooting rate of embryo culture seedling stem segment reaches 86.1%, and the transplanting survival rate reaches 88.5% by selecting good variety walnut seedling as parent female parent for hybridization.

Description

Walnut half-sibling family breeding method

Technical Field

The invention relates to the technical field of walnuts, in particular to a breeding method of a half-sibling family of walnuts.

Background

The walnut has rich nutrition, and has effects of invigorating kidney, moistening lung, moisturizing intestine, strengthening body constitution, nourishing brain, caring skin, and prolonging life. The walnut green seedcase contains abundant vitamin B and vitamin C, the content of which is 40-50 times of that of citrus pincers, and substances such as quercetin, kaempferol and the like, and can be used for treating some skin diseases and stomach neuralgia in traditional Chinese medicine; the green peel can also be used as a pesticide. At present, the walnut breeding mainly comprises a method for directly sowing and grafting good varieties, the walnut varieties are various at present, but the work of the selective breeding and directional cultivation of the good variety plants is less, the spare varieties are deficient, and although the domestic universities and colleges, scientific research institutions and technological enterprises are all carrying out the selective breeding, domestication and other works of the walnut seeds, the conventional walnut seedlings generally have the defects of long selective breeding period, low success probability and the like, so that the cultivation speed of the good walnut seedlings in China is slow, and the reserved varieties are few.

Disclosure of Invention

(one) solving the technical problems

Aiming at the defects of the prior art, the invention provides a breeding method of a half-sibling family of walnut, which has the advantages of higher germination rate of hybrid embryo and the like, and solves the problem of lower embryo survival rate of walnut seedlings.

(II) technical scheme

In order to achieve the aim of higher germination rate of the hybrid embryo, the invention provides the following technical scheme: a walnut half-sibling family breeding method comprises the following steps:

step one: parent selection: the ripple is soaking with the walnut; the ripple is multiplied by the cotton-sandwiched walnut; the ripple is soaking with little walnut; the ripple is soaking with the early fruit walnut; an interspecific hybrid combination; bubble x yanglin a; yun Lin A7 Xripple bubble; ripple x Xinzao 10; xinzao No. 10 Xripple bubble; bubble x Qinzao 13; xinzao 13 Xripple bubbles; large white shell x philic No. 10; xinzao No. 10 x white shell; white crust x Yun Lin A7; yun Lin A No. 7 x white crust; white crust x new No. 13; xinzao 13 # x large white shell; three X Xinzao No. 12; new morning No. 12 x three; three x new early 13; new early 13 # x three; three x Yun Lin A7; yun Lin A No. 7 x three. Intergeneric hybrid combination: the ripple is a bubble of thin-shell walnut; the walnut with thin shell is soaked in the water; xinzao 13 Xripple bubbles; apocarya x Xinzao 13;

step two: cultivating hybrid seedlings: soaking hybrid seeds in cold water for 4-6 d, sowing the hybrid seeds into a flowerpot greenhouse for germination acceleration, sowing 90-110 seeds, emergence of 68-76 plants, after germination, moving the hybrid seeds into a nursery for planting (plant row spacing is 20cm multiplied by 30 cm) in batches, and carrying out fine soil, fertilizer and water and pest management;

step three: early hybrid plant selection: continuously culturing, observing and selecting the hybrid Miao Yiru with the row spacing of 4m multiplied by 5m for the planting plants in the primary nursery of the hybrid Miao Yiru with the flowering and fruiting for l-3 years;

step four: subculture: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; 10-20 mg/L active carbon, 2-5 mg/LIBA, 0.2-0.5 mg/LNAA, 20-40 g/L sucrose and 4-6 g/L agar are added into the basic culture medium, and the pH value is 5.5-6.0; the culture conditions are as follows: the culture temperature is 23-27 ℃, the illumination intensity is 1400-1600 lux, and the illumination time is 8-10 hours/day;

step five: and (3) bagging: isolation generally requires bagging 3-5 days before the pollen of the male flowers is scattered, so that the development of female flowers can be influenced too early, and other pollen can be mixed easily later;

step six: after bagging isolation, observations are made daily for timely pollination. The temperature and the humidity in the bag are higher than those outside the bag, the development period of female flowers is 1-2 d earlier than that outside the bag, and the proper pollination period is 2-3 d after flowering, at the moment, the walnut stigma is changed from green to yellow green, and the walnut stigma is horizontally opened to two sides and shines and has mucus;

step seven: about 3-5 d after pollination, the stigmas are dry, about 10d of ovaries are quickly expanded, so that bags can be removed after about 1 week after pollination so as to facilitate fruit growth and timely picking, hybrid seeds are cultivated into seedlings, and after strict seedling selection, different clones are formed by adopting vegetative propagation methods such as budding, grafting and the like, and the quality of the clones is confirmed to be excellent and can be popularized to production;

preferably, the fifth step is bagging: the bagging material is preferably parchment paper or transparent paper, the specification of the bag is about 55cm long and 30cm wide, the larger leaves at the lower part of the branches are firstly cut off during bagging, then half of young leaves close to female flowers are cut off, a small amount of cotton is padded at the joint of the bag mouth and the branches, and the bag is tightly tied by a strapping tape so as to prevent other pollen from invading.

Preferably, after bagging and isolation in the step six, pollination is carried out before 10 a.m., the temperature is high in noon, a large amount of pollen is scattered from the parent tree, other pollen is easy to mix, the accuracy of hybridization is affected, a small opening is cut at the upper part of a bag opening when a pollen sprayer is used for pollination, and the pollen sprayer is inserted into a mouth of the pollen sprayer for pollination. When the brush pen or the cotton ball is used for picking pollen and pollinating, the bag is firstly removed or the upper part of the bag is cut off and then pollinated, after the pollinating is finished, the bag opening is folded, the bag is tightly held or bound again by a clip, and in order to improve the fruit setting rate, the pollinating is repeated for 2-3 times, namely, the pollinating is carried out 1 time every day or every other day, and the pollinating comprises the following raw materials in parts by weight: in the fourth subculture process: 13mg/L active carbon, 5mg/LIBA, 0.2g/LNAA, 30g/L sucrose and 4g/L agar are added into the basic culture medium, and the pH value is 5.8; the culture conditions are as follows: the cultivation temperature was 27℃and the illumination intensity was 1600lux, and the illumination time was 7.5 hours/day.

Preferably, the feed comprises the following raw materials in parts by weight: in the fourth subculture process: adding 12mg/L active carbon, 3mg/LIBA, 0.4g/LNAA, 30g/L sucrose and 6g/L agar into the basic culture medium, and having pH value of 5.6; the culture conditions are as follows: the culture temperature was 24℃and the illumination intensity was 1600lux, and the illumination time was 8 hours/day.

Preferably, the feed comprises the following raw materials in parts by weight: in the fourth subculture process: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; 15mg/L active carbon, 4mg/LIBA, 0.4mg/LNAA, 25g/L sucrose and 5g/L agar are added into the basic culture medium, and the pH value is 5.8; the culture conditions are as follows: the cultivation temperature was 26℃and the illumination intensity was 1500lux, and the illumination time was 8.5 hours/day.

Preferably, the method comprises the following steps: in the fourth subculture process: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; adding 14mg/L active carbon, 3mg/LIBA, 0.2mg/LNAA, 30g/L sucrose and 4g/L agar into the basic culture medium, and having pH value of 5.9; the culture conditions are as follows: the cultivation temperature is 28 ℃, the illumination intensity is 1600lux, and the illumination time is 9 hours/day.

(III) beneficial effects

Compared with the prior art, the invention provides a walnut half-sibling family breeding method, which has the following beneficial effects:

combining the traditional breeding method with the tissue culture technology, and selecting a good variety walnut seedling as a parent female parent for hybridization, wherein the germination rate of hybrid young embryo reaches 96%, the rooting rate of the stem section of the embryo culture seedling reaches 86.1%, and the transplanting survival rate reaches 88.5%;

the component concentration of nutrient solution in the culture medium improves the shell breaking rate in walnut breeding, so that the breeding survival rate is higher, and the efficiency of cross breeding is improved;

through the pest management of the hybrid seeds in the cross breeding process, the influence of the external environment on the cultivation effect in the cross penetration can be prevented.

Detailed Description

The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Embodiment one: a walnut half-sibling family breeding method comprises the following steps:

step one: parent selection: the ripple is soaking with the walnut; the ripple is multiplied by the cotton-sandwiched walnut; the ripple is soaking with little walnut; the ripple is soaking with the early fruit walnut; an interspecific hybrid combination; bubble x yanglin a; yun Lin A7 Xripple bubble; ripple x Xinzao 10; xinzao No. 10 Xripple bubble; bubble x Qinzao 13; xinzao 13 Xripple bubbles; large white shell x philic No. 10; xinzao No. 10 x white shell; white crust x Yun Lin A7; yun Lin A No. 7 x white crust; white crust x new No. 13; xinzao 13 # x large white shell; three X Xinzao No. 12; new morning No. 12 x three; three x new early 13; new early 13 # x three; three x Yun Lin A7; yun Lin A No. 7 x three; intergeneric hybrid combination: the ripple is a bubble of thin-shell walnut; the walnut with thin shell is soaked in the water; xinzao 13 Xripple bubbles; apocarya x Xinzao 13;

step two: cultivating hybrid seedlings: soaking hybrid seeds in cold water for 4 days, sowing the hybrid seeds into a flowerpot greenhouse for germination acceleration, sowing 100 seeds, emergence of 68 plants, after germination, moving the hybrid seeds into a nursery for planting in batches (plant row spacing is 20cm & lt 30 & gt), and carrying out fine soil, fertilizer and water and pest management;

step three: early hybrid plant selection: continuously culturing, observing and selecting the hybrid Miao Yiru with the row spacing of 4m multiplied by 5m;

step four: subculture: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; the material comprises the following raw materials in parts by weight: 13mg/L active carbon, 5mg/LIBA, 0.2g/LNAA, 30g/L sucrose and 4g/L agar are added into the basic culture medium, and the pH value is 5.8; the culture conditions are as follows: the culture temperature is 27 ℃, the illumination intensity is 1600lux, and the illumination time is 7.5 hours/day;

step five: and (3) bagging: isolation generally requires bagging 4d before pollen scattering of male flowers, which can affect the development of female flowers too early and is easy to mix with other pollen later; the bagging material is preferably parchment paper or transparent paper, the specification of the bag is about 55cm long and 30cm wide, the larger leaves at the lower part of the branches are firstly cut off during bagging, then half of young leaves close to female flowers are cut off, a small amount of cotton is padded at the joint of the bag mouth and the branches, and the bag is tightly tied by a strapping tape so as to prevent other pollen from invading;

step six: after bagging isolation, observations are made daily for timely pollination. The temperature and humidity in the bag are higher than those in the bag, the development period of female flowers is 1d earlier than that of female flowers outside the bag, and the proper pollination period is 2d after flowering, at the moment, the walnut stigmas are changed from green to yellow green, the walnut stigmas are horizontally opened to two sides, the walnut stigmas are shiny and have mucus, the pollination is carried out before 10 a morning, the temperature of noon is high, a large amount of pollen is scattered by a female tree, other pollen is easy to mix, the accuracy of hybridization is influenced, a small opening is cut at the upper part of a bag opening when the pollination is carried out by a powder sprayer, and the pollination is carried out by inserting the powder sprayer mouth;

step seven: after pollination, about 3d of the stigmas of the walnuts are dried, about 10d of the ovaries are quickly expanded, so that the bags can be removed after about 1 week of pollination, fruits can grow and timely picked, hybrid seeds are cultivated into seedlings, and after strict seedling selection, different asexual propagation methods such as budding, grafting and the like are adopted to form different asexual lines, the quality of the asexual lines is confirmed to be excellent, and the asexual lines can be popularized to production.

Embodiment two: a walnut half-sibling family breeding method comprises the following steps:

step two: cultivating hybrid seedlings: soaking hybrid seeds in cold water for 6 days, sowing the hybrid seeds into a flowerpot greenhouse for accelerating germination, sowing 102 grains, emergence of 73 plants, after germination, moving the hybrid seeds into a nursery for planting in batches (plant row spacing is 20cm multiplied by 30 cm), and carrying out fine soil, fertilizer and water and pest management;

step three: early hybrid plant selection: continuously culturing, observing and selecting the hybrid Miao Yiru with flowering and fruiting in 3 years in a primary nursery, and enabling the row spacing of the field planting plants to be 4m multiplied by 5m;

step four: subculture: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; adding 12mg/L active carbon, 3mg/LIBA, 0.4g/LNAA, 30g/L sucrose and 6g/L agar into the basic culture medium, and having pH value of 5.6; the culture conditions are as follows: the culture temperature is 24 ℃, the illumination intensity is 1600lux, and the illumination time is 8 hours/day;

step five: and (3) bagging: isolation generally requires that the development of female flowers is affected too early before the male flowers scatter powder, other pollens are mixed too late, parchment paper or transparent paper is preferably selected as a bagging material, the specification of the bag is about 55cm long and 30cm wide, the larger leaves at the lower part of branches are firstly cut off during bagging, then half of young leaves close to the female flowers are cut off, a small amount of cotton is padded at the joint of the bag mouth and the branches, and the bag mouth is fastened by a strapping tape so as to prevent other pollens from invading.

Step six: after bagging isolation, observations are made daily for timely pollination. The temperature and humidity in the bag are higher than those in the bag, the development period of female flowers is 2d earlier than that in the bag, and the proper pollination period is 2d after flowering, at this time, the walnut stigma is changed from turquoise to turquoise, and the walnut stigma is horizontally opened to two sides, shines and has mucus, pollination is carried out before 10 a.m., the temperature is high at noon, a large amount of pollen is scattered by the female tree, other pollen is easy to mix, the accuracy of hybridization is influenced, and when the pollination is carried out by a powder sprayer, a small opening is cut at the upper part of the bag mouth, and the pollination is carried out by inserting the powder sprayer mouth. When the writing brush or cotton ball is used for picking pollen and pollinating, firstly removing the bag or cutting the upper part of the bag and then pollinating, after finishing pollinating, folding the bag opening, and then fastening or binding the bag again by using a clip, and in order to improve the fruit setting rate, pollinating for 2 times repeatedly, namely pollinating for 1 time every day or every other day;

Embodiment III: a walnut half-sibling family breeding method comprises the following steps:

step two: cultivating hybrid seedlings: soaking hybrid seeds in cold water for 4-6 d, sowing the hybrid seeds into a flowerpot greenhouse for germination acceleration, sowing 93 seeds, emergence of 71 plants, after germination, moving the hybrid seeds into nursery planting in batches (plant row spacing is 20cm multiplied by 30 cm), and carrying out fine soil, fertilizer and water and pest management;

step three: early hybrid plant selection: continuously culturing, observing and selecting the hybrid Miao Yiru with flowering and fruiting in 2 years in a primary nursery, and enabling the row spacing of the field planting plants to be 4m multiplied by 5m;

step four: subculture: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; 15mg/L active carbon, 4mg/LIBA, 0.4mg/LNAA, 25g/L sucrose and 5g/L agar are added into the basic culture medium, and the pH value is 5.8; the culture conditions are as follows: the culture temperature is 26 ℃, the illumination intensity is 1500lux, and the illumination time is 8.5 hours/day;

step five: and (3) bagging: isolation generally requires 3d bagging before pollen scattering of male flowers, which can affect the development of female flowers too early and is easy to mix with other pollen later; the bagging material is preferably parchment paper or transparent paper, the specification of the bag is about 55cm long and 30cm wide, the larger leaves at the lower part of the branches are firstly cut off during bagging, then half of young leaves close to female flowers are cut off, a small amount of cotton is padded at the joint of the bag mouth and the branches, and the bag is tightly tied by a strapping tape so as to prevent other pollen from invading;

step six: after bagging isolation, observations are made daily for timely pollination. The temperature and humidity in the bag are higher than those in the bag, the development period of female flowers is 1d earlier than that in the bag, and the proper pollination period is 2d after flowering, at this time, the walnut stigmas are changed from green to yellow green, the walnut stigmas are horizontally opened to two sides, the walnut stigmas are shined and have mucus, the pollination is carried out before 10 a.m., the temperature is high in noon, a large amount of pollen is scattered by the female tree, other pollen is easy to mix, the accuracy of hybridization is influenced, and when the pollination is carried out by a powder sprayer, a small opening is cut at the upper part of the mouth of the bag, and the pollination is carried out by inserting the powder sprayer mouth. When the brush pen or the cotton ball is used for picking pollen and pollinating, the bag is firstly removed or the upper part of the bag is cut off and then pollinated, after the pollinating is finished, the bag opening is folded, the bag is tightly held or bound again by a clip, and in order to improve the fruit setting rate, the pollinating is repeated for 3 times, namely, the pollinating is carried out 1 time every day or every other day, and the pollinating comprises the following raw materials in parts by weight: in the fourth subculture process: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium;

Embodiment four: a walnut half-sibling family breeding method comprises the following steps:

step two: cultivating hybrid seedlings: soaking hybrid seeds in cold water for 4 days, sowing the hybrid seeds into a flowerpot greenhouse for accelerating germination, sowing 100 seeds, emergence of 67 plants, after germination, moving the hybrid seeds into a nursery for planting in batches (plant row spacing is 20cm multiplied by 30 cm), and carrying out fine soil, fertilizer and water and pest management;

step four: subculture: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; adding 14mg/L active carbon, 3mg/LIBA, 0.2mg/LNAA, 30g/L sucrose and 4g/L agar into the basic culture medium, and having pH value of 5.9; the culture conditions are as follows: the culture temperature is 28 ℃, the illumination intensity is 1600lux, and the illumination time is 9 hours/day;

step five: and (3) bagging: isolation generally requires bagging for 4 days before pollen scattering of male flowers, which affects female flowers in early time and is easy to mix with other pollen later, the bagging material is preferably parchment or transparent paper, the specification of the bag is about 55cm long and 30cm wide, the blades on the lower parts of branches are firstly cut off during bagging, then half of young leaves close to female flowers are cut off, small amount of cotton is padded at the joint of the bag mouth and the branches, and the bag is fastened by a strapping tape so as to prevent other pollen from invading;

step six: after bagging isolation, observations are made daily for timely pollination. The temperature and humidity in the bag are higher than those in the bag, the development period of female flowers is 2d earlier than that in the bag, the proper pollination period is 3d after flowering, at this time, the walnut stigma is changed from green to yellow green, and is horizontally opened to two sides, the walnut stigma shines and has mucus, when the pollen is dipped by a writing brush or cotton ball for pollination, the bag is firstly removed or the upper part of the bag is cut off and then pollinated, after the pollination is finished, the bag mouth is folded and then the bag is tightly or readying by a clip, and in order to improve the fruit setting rate, the pollination is repeated for 3 times, namely, the pollination is carried out 1 time every day or every other day

The beneficial effects of the invention are as follows: by selecting the excellent variety walnut seedlings as parent female parent for hybridization, the germination rate of hybrid young embryo reaches 96%, the rooting rate of embryo culture seedling stem segment reaches 86.1%, and the transplanting survival rate reaches 88.5%;

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The walnut half-sibling family breeding method is characterized by comprising the following steps:

step seven: after pollination, the stigmas of the walnuts are about 3-5 days dry, and the ovaries of the walnuts are about 10 days fast to expand, so that the bag can be removed after about 1 week of pollination, fruits can grow and timely picked, hybrid seeds are cultivated into seedlings, and after strict seedling selection, different clone lines are formed by adopting a bud grafting method, a branch grafting method and other asexual propagation methods, the quality of the asexual lines is confirmed to be excellent, and the asexual lines can be popularized to production.

2. The method for breeding half-sibling families of walnuts according to claim 1, wherein the fifth step is bagging: the bagging material is preferably parchment paper or transparent paper, the specification of the bag is about 55cm long and 30cm wide, the larger leaves at the lower part of the branches are firstly cut off during bagging, then half of young leaves close to female flowers are cut off, a small amount of cotton is padded at the joint of the bag mouth and the branches, and the bag is tightly tied by a strapping tape so as to prevent other pollen from invading.

3. The method for breeding half-sibling families of walnuts according to claim 1, wherein after bagging and isolation in the step six, pollination is carried out before 10 a.m., the temperature is high, a large amount of pollen is scattered by a parent tree, other pollen is easy to mix, the accuracy of hybridization is affected, a small opening is cut at the upper part of a bag mouth when pollination is carried out by a duster, and the duster is inserted into a mouth of the duster for pollination.

4. The method for breeding half-sibling families of walnuts according to claim 1, wherein after bagging and isolation in the sixth step, when pollinating pollen by using a writing brush or cotton ball, the bag should be removed or the upper part of the bag should be cut off and pollinated, after finishing pollinating, the bag mouth should be folded after the bag mouth is folded, the bag should be fastened or bound again by using a clip, and in order to improve fruit setting rate, pollinating should be repeated for 2-3 times, namely, pollinating 1 time every day or every other day.

5. The method for breeding the half-sibling families of the walnuts according to claim 1, which is characterized by comprising the following raw materials in parts by weight: in the fourth subculture process: 13mg/L active carbon, 5mg/LIBA, 0.2g/LNAA, 30g/L sucrose and 4g/L agar are added into the basic culture medium, and the pH value is 5.8; the culture conditions are as follows: the cultivation temperature was 27℃and the illumination intensity was 1600lux, and the illumination time was 7.5 hours/day.

6. The method for breeding the half-sibling families of the walnuts according to claim 1, which is characterized by comprising the following raw materials in parts by weight: in the fourth subculture process: adding 12mg/L active carbon, 3mg/LIBA, 0.4g/LNAA, 30g/L sucrose and 6g/L agar into the basic culture medium, and having pH value of 5.6; the culture conditions are as follows: the culture temperature was 24℃and the illumination intensity was 1600lux, and the illumination time was 8 hours/day.

7. The method for breeding the half-sibling families of the walnuts according to claim 1, which is characterized by comprising the following raw materials in parts by weight: in the fourth subculture process: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; 15mg/L active carbon, 4mg/LIBA, 0.4mg/LNAA, 25g/L sucrose and 5g/L agar are added into the basic culture medium, and the pH value is 5.8; the culture conditions are as follows: the cultivation temperature was 26℃and the illumination intensity was 1500lux, and the illumination time was 8.5 hours/day.

8. The method for breeding the half-sibling families of the walnuts according to claim 1, which is characterized by comprising the following raw materials in parts by weight: in the fourth subculture process: performing secondary culture on the stem segments of the embryo culture seedlings in a secondary culture medium; adding 14mg/L active carbon, 3mg/LIBA, 0.2mg/LNAA, 30g/L sucrose and 4g/L agar into the basic culture medium, and having pH value of 5.9; the culture conditions are as follows: the cultivation temperature is 28 ℃, the illumination intensity is 1600lux, and the illumination time is 9 hours/day.