CN116686703B - Method for creating new germplasm by hybridization of macadimia nut and cesium radiation - Google Patents

Abstract

The present invention discloses a method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps: (1) male parent selection; (2) macadamia nut male parent pretreatment; (3) male parent pollen pretreatment; (4) cesium 137 mutagenesis treatment; (5) pollination; (6) harvesting and selecting products. First, a macadamia nut male parent variety whose data such as the number of pollinated flowers, fruiting rate, and fruiting rate are much higher than those of a control group is selected, and then the macadamia nut male parent is subjected to three-stage light control, water control, and spraying of a pretreatment liquid, and the male parent pollen is pretreated at the same time, so that the pollen can be adapted to light radiation in advance, the adaptability of the pollen to cesium 137 ray irradiation is enhanced, and the sensitivity of the pollen to cesium 137 ray irradiation is reduced, which plays a role in increasing the semi-lethal irradiation amount of the pollen, thereby promoting the irradiation mutagenesis of macadamia nut pollen. The combination of three-stage light control, cesium 137 ray irradiation and other operations can accelerate the mutation speed of macadamia nut seeds, improve the mutation rate, and obtain more new macadamia nut varieties.

Description

A method for creating new germplasm by hybridization and cesium radiation of macadamia nuts

Technical Field

The present invention relates to the field of agricultural planting technology, and in particular to a method for creating new germplasm by hybridization of macadamia nuts and cesium radiation.

Background technique

Macadamia nuts are also known as Queensland chestnuts, Australian walnuts, macadamia nuts, and Queensland nuts. They are a type of tree nut native to Australia. Macadamia nuts are evergreen trees and dicotyledonous plants. The tree has a tall crown, with 3 to 4 leaves arranged in whorls, which are lanceolate, leathery, smooth, and have thorn-like serrations on the edges. The racemes are axillary, the flowers are beige, the fruit is spherical, the fruit leather is leathery, the endocarp is hard, and the seed kernel is beige to light brown. It is suitable for growing in mild, humid, and windy areas. Among the many dried fruits in the world, macadamia nuts have the highest economic value and have always enjoyed the reputation of "the king of dried fruits". The kernel of macadamia nuts is rich in nutrients (milky white), its outer peel is green, the endocarp is hard and brown, and the single fruit weighs 15-16 grams, with an oil content of about 70%, protein of 9%, and 17 kinds of amino acids including 8 essential amino acids for the human body. It is also rich in minerals and vitamins.

Macadamia nuts are prone to sterility due to self-pollination. When planted in Guangxi, varieties suitable for planting in Guangxi can be selected: Guire No. 1, A16, OC, 695, etc. for hybridization. At present, macadamia nuts are usually bred by hybrid breeding, and there is no breeding method combining hybrid breeding with cesium radiation. For this reason, the present application method first selects the male and female parent combination with the best artificial pollination results, and then adjusts the conditions of each hybrid breeding to obtain a new and reliable breeding method combining hybrid breeding with cesium radiation.

Summary of the invention

In view of the shortcomings of the prior art, the object of the present invention is to provide a method for creating new germplasm by hybridization and cesium radiation of macadamia nuts, which combines hybrid breeding with cesium radiation and has a good mutagenesis effect.

In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for creating new germplasm by hybridization and cesium radiation of macadamia nuts, comprising the following steps:

(1) Selection of male parent: Using "Guire No. 1" as the female parent and other varieties of macadamia as the male parent, artificial pollination experiments were carried out separately, and the varieties with good pollination effect and high fruit setting rate were selected as macadamia male parents;

(2) Pre-treatment of macadamia nut parent:

2.1) Light control: 3 months before the budding period of the flower spike, three-stage light control is carried out at night;

One stage of light control: the light time is controlled at 3-5h, the light intensity is controlled at 15-20Lux, and the duration of one stage of light is 20-30 days;

Two-stage lighting control: lighting time is controlled at 6-8h, light intensity is controlled at 25-30Lux, and the duration of the second stage lighting is 20-30 days;

Three-stage light control: the light duration is controlled at 4-6 hours, the light intensity is controlled at 40-45 Lux, and the three-stage light duration lasts until the early flowering period;

2.2) Water control: 2 months before the budding stage of the flower spike, water the roots of the macadamia nut male plant once a week, and spray the entire plant with water until the stems and leaves of the male plant are all moist;

2.3) Spraying pre-treatment solution: 10-15 days before the inflorescence bud stage and during the inflorescence bud stage, spray the whole plant with pre-treatment solution until the stems and leaves of the male parent plant are completely wet; the pre-treatment solution uses water as a solvent and contains 45-50 g/kg urea, 20-25 g/kg boric acid and 10-15 g/kg calcium gluconate;

(3) Pretreatment of male parent pollen: After the male parent plant in step 2.3) blooms, pollen is collected to obtain male parent pollen; the pretreatment solution in step 2.3) is diluted 50 to 70 times to obtain male parent pollen treatment solution; male parent pollen is placed in the male parent pollen treatment solution, and the mixture is mixed evenly to obtain pollen to be irradiated and induced to mutagenesis;

(4) Cesium-137 mutagenesis treatment: The pollen to be irradiated is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 5 to 10 Gy to obtain irradiated pollen;

(5) Pollination: artificial pollination of irradiated pollen and thinning of flowers and fruits;

(6) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits, and further observe and screen them to obtain new varieties of macadamia nuts.

Furthermore, the macadamia nut male parent in step (1) is variety 695.

Furthermore, in the step 2.1), three stages of light control are performed at night 3 months before the budding period of the flower spike;

One stage of light control: the light time is controlled at 4-5h, the light intensity is controlled at 18-20Lux, and the duration of one stage of light is 25-30 days;

Two-stage light control: light time is controlled at 7-8h, light intensity is controlled at 27-30Lux, and the duration of the second stage light is 27-30 days;

Three-stage light control: the light time is controlled at 4.5-6h, the light intensity is controlled at 42-45Lux, and the three-stage light time lasts until the early flowering period.

Furthermore, in the three-stage illumination control in step 2.1), the daily illumination start time is 20:00 in the evening.

Furthermore, the pretreatment solution in step 2.3) uses water as a solvent and contains urea at a concentration of 48 to 50 g/kg, boric acid at a concentration of 23 to 25 g/kg, and calcium gluconate at a concentration of 14 to 15 g/kg.

Furthermore, the pretreatment solution in step 2.3) also includes folic acid at a concentration of 0.5 to 0.8 mg/kg.

Furthermore, the pretreatment liquid in step (3) is diluted 65 to 70 times to obtain the male parent pollen treatment liquid; the dosage of the male parent pollen treatment liquid is 500 to 600 ml/g pollen.

Furthermore, in the step (4), the pollen to be irradiated and induced by radiation is irradiated with ¹³⁷ Cs-γ rays, the irradiation dose rate is 0.75 Gy/min, and the irradiation dose intensity is 8 to 10 Gy, so as to obtain irradiated pollen.

Furthermore, in the step (5), when the hybrid fruit has been developing for 100 to 120 days, a hybrid fruit treatment solution is sprayed until the outer surface of the hybrid fruit is completely wetted, wherein the hybrid fruit treatment solution uses water as a solvent and contains prochloraz at a concentration of 25 to 30 g/100 kg, zinc sulfate at a concentration of 30 to 35 g/kg, calcium chloride at a concentration of 50 to 65 g/kg, ammonium molybdate at a concentration of 10 to 15 g/kg, and manganese sulfate at a concentration of 5 to 8 g/kg.

Furthermore, in the step (5), when the hybrid fruit has been developing for 110 to 120 days, a hybrid fruit treatment solution is sprayed until the outer surface of the hybrid fruit is completely wetted, wherein the hybrid fruit treatment solution uses water as a solvent and contains prochloraz at a concentration of 28 to 30 g/100 kg, zinc sulfate at a concentration of 32 to 35 g/kg, calcium chloride at a concentration of 55 to 65 g/kg, ammonium molybdate at a concentration of 12 to 15 g/kg, and manganese sulfate at a concentration of 6 to 8 g/kg.

The present invention provides a method for creating new germplasm by hybridization of macadamia nuts and cesium radiation. The method uses "Guire No. 1" as the female parent and other varieties of macadamia nuts as the male parent. Artificial pollination experiments are carried out respectively, and varieties with good pollination effect and high fruit setting rate are selected as macadamia nut male parents. During the experiment, the pollen of the male parents of four varieties, A16, JW, OC, and 695, is first collected with a brush, and then the original pollen on the stigma of the female parent "Guire No. 1" is brushed off. Finally, the pollen of each male parent is gently brushed on the stigma of the female parent with a brush. The pollination results are shown in Table 1 below;

Table 1

From the pollination experimental results in Table 1 above, it can be seen that same-flower pollination basically does not produce fruit, and the pollination result of the experimental group of Guire No. 1 X695 is the best, and its data such as the number of pollinated flowers, average fruit bearing value, fruit setting rate, and fruit setting rate are much higher than those of the control group; therefore, the present invention mainly conducts research with "Guire No. 1" as the female parent and No. 695 as the male parent.

The beneficial effects of the present invention are as follows: the method for creating new germplasm by hybridization and cesium radiation of macadamia nuts of the present invention comprises the following steps: firstly, under natural artificial pollination conditions, a macadamia nut male parent variety is selected, whose data such as the number of pollinated flowers, average fruit bearing value, fruit setting rate, and fruit setting rate are far higher than those of a control group, so as to facilitate subsequent artificial pollination experiments; three-stage light control, water control, and spraying of a pretreatment liquid are performed on the macadamia nut male parent, and at the same time, the male parent pollen is pretreated, so that the pollen can adapt to light radiation in advance, enhance the adaptability of the pollen to cesium-137 ray irradiation, reduce the sensitivity of the pollen to cesium-137 ray irradiation, and increase the semi-lethal irradiation amount of the pollen, thereby promoting radiation mutagenesis of macadamia nut pollen; in addition, the combination of three-stage light control, cesium-137 ray irradiation, spraying of a pretreatment liquid, and the like can also further accelerate the mutation speed of macadamia nut seeds and improve the mutation rate, thereby obtaining a new macadamia nut variety.

The invention discloses a method for creating new germplasm by hybridizing macadamia nuts and cesium radiation. The pre-treatment liquid also includes folic acid, which can be directly absorbed and utilized by female flowers, so that the female flowers have better pollination effect and higher fruit setting rate. The hybrid fruit treatment liquid is sprayed, and the prochloraz in the hybrid fruit treatment liquid mainly prevents and controls the occurrence of fruit diseases. The hybrid fruit treatment liquid can also supplement zinc, calcium, molybdenum, manganese and other elements for macadamia nut plants, avoid the deficiency of zinc, calcium, molybdenum, manganese and other elements in fruits, root systems and leaves caused by continuous high temperature, avoid premature fruit drop, and is beneficial to the acquisition of new varieties of macadamia nuts.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a picture of an experiment of pollination according to the method of the present invention;

FIG2 is a picture of the germination of seeds obtained by pollination treatment according to the method of the present invention;

FIG. 3 is a picture of seed leaf variation obtained by the experiment of the method of the present invention.

Detailed ways

The following embodiments may help those skilled in the art to more fully understand the present invention, but shall not limit the present invention in any way.

Example 1

A method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps:

(1) Selection of male parent: "Guire No. 1" was used as the female parent and "No. 695" as the male parent; the pollination site was located in Nanning, Guangxi; the soil was clay soil, the tillage layer was 25 cm, the soil contained 1.0% organic matter, and the soil pH was 4.5;

(2) Pre-treatment of macadamia nut parent:

2.1) Light control: Three months before the budding period of the flower spike, three-stage light control is carried out at night, and the starting time of light is 20:00 in the evening every day;

One stage of light control: the light time is controlled at 3h, the light intensity is controlled at 15Lux, and the duration of one stage of light is 20 days;

Second stage lighting control: lighting time is controlled at 6h, light intensity is controlled at 25Lux, second stage lighting duration: 20 days;

Three-stage light control: the light duration is controlled at 4h, the light intensity is controlled at 40Lux, and the three-stage light duration lasts until the early flowering period;

2.2) Water control: 2 months before the budding stage of the flower spike, water the roots of the macadamia nut male plant once a week, and spray the entire plant with water until the stems and leaves of the male plant are all moist;

2.3) Spraying pre-treatment solution: 10 days before the inflorescence bud stage and at the inflorescence bud stage, spray the whole plant with pre-treatment solution until the stems and leaves of the male parent plant are completely wet; the pre-treatment solution uses water as a solvent and contains 45g/kg urea, 20g/kg boric acid, 10g/kg calcium gluconate, and 0.5mg/kg folic acid;

(3) Pretreatment of male parent pollen: After the male parent plant in step 2.3) blooms, collect pollen with a brush to obtain male parent pollen; dilute the pretreatment solution in step 2.3) by 50 times to obtain male parent pollen treatment solution; put the male parent pollen and the male parent pollen treatment solution into a finger-shaped tube together, with the amount of male parent pollen treatment solution per gram of pollen being 500 ml, and mix them evenly in the finger-shaped tube to obtain pollen to be irradiated and induced;

(4) Cesium-137 mutagenesis treatment: The pollen to be induced by radiation is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 5 Gy to obtain irradiated pollen;

(5) Pollination: artificially emasculate the flowers of the female parent, artificially pollinate the irradiated pollen, label the flowers, and thin out the fruits. During this period, field management is performed on the female parent plants, pests and diseases are promptly controlled, and sufficient water and fertility are ensured to ensure the normal development and maturity of the hybrid fruits. After the hybrid fruits have developed for 100 days, a hybrid fruit treatment liquid is sprayed until the outer surface of the hybrid fruits is completely wet. The hybrid fruit treatment liquid uses water as a solvent and contains 25 g/100 kg of prochloraz, 30 g/kg of zinc sulfate, 50 g/kg of calcium chloride, 10 g/kg of ammonium molybdate, and 5 g/kg of manganese sulfate.

(6) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits, and further observe and screen them to obtain new varieties of macadamia nuts.

Example 2

A method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps:

(1) Selection of male parent: "Guire No. 1" was used as the female parent and "No. 695" as the male parent; the pollination site was located in Nanning, Guangxi; the soil was clay soil, the tillage layer was 25 cm, the soil contained 1.0% organic matter, and the soil pH was 4.5;

(2) Pre-treatment of macadamia nut parent:

2.1) Light control: Three months before the budding period of the flower spike, three-stage light control is carried out at night, and the starting time of light is 20:00 in the evening every day;

One-stage light control: the light time is controlled at 5h, the light intensity is controlled at 20Lux, and the duration of one stage of light is 30 days;

Two-stage lighting control: lighting time is controlled at 8h, light intensity is controlled at 30Lux, and the duration of the second stage lighting is 30 days;

Three-stage light control: the light duration is controlled at 6h, the light intensity is controlled at 45Lux, and the three-stage light duration lasts until the early flowering period;

2.2) Water control: 2 months before the budding stage of the flower spike, water the roots of the macadamia nut male plant once a week, and spray the entire plant with water until the stems and leaves of the male plant are all moist;

2.3) Spraying pre-treatment solution: Spray the whole plant with pre-treatment solution 15 days before the inflorescence bud stage and during the inflorescence bud stage until the stems and leaves of the male parent plant are completely wet; the pre-treatment solution uses water as a solvent and contains 50g/kg urea, 25g/kg boric acid, 15g/kg calcium gluconate, and 0.8mg/kg folic acid;

(3) Pretreatment of male parent pollen: After the male parent plant in step 2.3) blooms, collect pollen with a brush to obtain male parent pollen; dilute the pretreatment solution in step 2.3) by 70 times to obtain male parent pollen treatment solution; put the male parent pollen and the male parent pollen treatment solution into a finger-shaped tube together, with the amount of male parent pollen treatment solution per gram of pollen being 600 ml, and mix them evenly in the finger-shaped tube to obtain pollen to be irradiated and induced;

(4) Cesium-137 mutagenesis treatment: The pollen to be induced by radiation is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 10 Gy to obtain irradiated pollen;

(5) Pollination: artificially emasculate the flowers of the female parent, artificially pollinate the irradiated pollen, label the flowers, and thin out the flowers and fruits. During this period, field management is carried out on the female parent plants, pests and diseases are promptly prevented and controlled, and sufficient water and fertility are ensured to ensure the normal development and maturity of the hybrid fruits. After the hybrid fruits have developed for 120 days, a hybrid fruit treatment liquid is sprayed until the outer surface of the hybrid fruits is completely wet. The hybrid fruit treatment liquid uses water as a solvent and contains 30 g/100 kg of prochloraz, 35 g/kg of zinc sulfate, 65 g/kg of calcium chloride, 15 g/kg of ammonium molybdate, and 8 g/kg of manganese sulfate.

(6) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits, and further observe and screen them to obtain new varieties of macadamia nuts.

Example 3

A method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps:

(1) Selection of male parent: "Guire No. 1" was used as the female parent and "No. 695" as the male parent; the pollination site was located in Nanning, Guangxi; the soil was clay soil, the tillage layer was 25 cm, the soil contained 1.0% organic matter, and the soil pH was 4.5;

(2) Pre-treatment of macadamia nut parent:

2.1) Light control: Three months before the budding period of the flower spike, three-stage light control is carried out at night, and the starting time of light is 20:00 in the evening every day;

One stage of light control: the light time is controlled at 4h, the light intensity is controlled at 18Lux, and the duration of one stage of light is 25 days;

Two-stage lighting control: lighting time is controlled at 7h, light intensity is controlled at 27Lux, and the duration of the second stage lighting is 27 days;

Three-stage light control: the light duration is controlled at 4.5h, the light intensity is controlled at 42Lux, and the three-stage light duration lasts until the early flowering period;

2.2) Water control: 2 months before the budding stage of the flower spike, water the roots of the macadamia nut male plant once a week, and spray the entire plant with water until the stems and leaves of the male plant are all moist;

2.3) Spraying pre-treatment solution: 12 days before the inflorescence bud stage and during the inflorescence bud stage, spray the whole plant with pre-treatment solution until the stems and leaves of the male parent plant are completely wet; the pre-treatment solution uses water as a solvent and contains 48g/kg urea, 23g/kg boric acid, 14g/kg calcium gluconate, and 0.6mg/kg folic acid;

(3) Pretreatment of male parent pollen: After the male parent plant in step 2.3) blooms, collect pollen with a brush to obtain male parent pollen; dilute the pretreatment solution in step 2.3) by 60 times to obtain male parent pollen treatment solution; put the male parent pollen and the male parent pollen treatment solution into a finger-shaped tube together, with the amount of male parent pollen treatment solution per gram of pollen being 550 ml, and mix them evenly in the finger-shaped tube to obtain pollen to be irradiated and induced;

(4) Cesium-137 mutagenesis treatment: The pollen to be induced by radiation is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 8 Gy to obtain irradiated pollen;

(5) Pollination: artificially emasculate the flowers of the female parent, artificially pollinate the irradiated pollen, label the flowers, and thin out the flowers and fruits. During this period, field management is carried out on the female parent plants, pests and diseases are promptly controlled, and sufficient water and fertility are ensured to ensure the normal development and maturity of the hybrid fruits. After the hybrid fruits have developed for 110 days, a hybrid fruit treatment liquid is sprayed until the outer surface of the hybrid fruits is completely wet. The hybrid fruit treatment liquid uses water as a solvent and contains 28 g/100 kg of prochloraz, 32 g/kg of zinc sulfate, 55 g/kg of calcium chloride, 12 g/kg of ammonium molybdate, and 6 g/kg of manganese sulfate.

(6) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits, and further observe and screen them to obtain new varieties of macadamia nuts.

Example 4

A method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps:

(1) Selection of male parent: "Guire No. 1" was selected as the female parent and "No. 695" as the male parent; the pollination site was located in Nanning, Guangxi; the soil was clay soil, the tillage layer was 25 cm, the soil contained 1.0% organic matter, and the soil pH was 4.5;

(2) Pre-treatment of macadamia nut parent:

2.1) Light control: Three months before the budding period of the flower spike, three-stage light control is carried out at night, and the starting time of light is 20:00 in the evening every day;

One stage of light control: the light time is controlled at 4h, the light intensity is controlled at 18Lux, and the duration of one stage of light is 25 days;

Two-stage lighting control: lighting time is controlled at 7h, light intensity is controlled at 27Lux, and the duration of the second stage lighting is 27 days;

Three-stage light control: the light duration is controlled at 4.5h, the light intensity is controlled at 42Lux, and the three-stage light duration lasts until the early flowering period;

2.2) Water control: 2 months before the budding stage of the flower spike, water the roots of the macadamia nut male plant once a week, and spray the entire plant with water until the stems and leaves of the male plant are all moist;

2.3) Spraying pre-treatment solution: 12 days before the inflorescence bud stage and at the inflorescence bud stage, spray the whole plant with pre-treatment solution until the stems and leaves of the male parent plant are completely wet; the pre-treatment solution uses water as a solvent and contains 48g/kg urea, 23g/kg boric acid, and 14g/kg calcium gluconate;

(3) Pretreatment of male parent pollen: After the male parent plant in step 2.3) blooms, collect pollen with a brush to obtain male parent pollen; dilute the pretreatment solution in step 2.3) by 60 times to obtain male parent pollen treatment solution; put the male parent pollen and the male parent pollen treatment solution into a finger-shaped tube together, with the amount of male parent pollen treatment solution per gram of pollen being 550 ml, and mix them evenly in the finger-shaped tube to obtain pollen to be irradiated and induced;

(4) Cesium-137 mutagenesis treatment: The pollen to be induced by radiation is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 8 Gy to obtain irradiated pollen;

(5) Pollination: artificially emasculate the flowers of the female parent, artificially pollinate the irradiated pollen, label the flowers, and thin out the flowers and fruits. During this period, field management is carried out on the female parent plants, pests and diseases are promptly controlled, and sufficient water and fertility are ensured to ensure the normal development and maturity of the hybrid fruits. After the hybrid fruits have developed for 110 days, a hybrid fruit treatment liquid is sprayed until the outer surface of the hybrid fruits is completely wet. The hybrid fruit treatment liquid uses water as a solvent and contains 28 g/100 kg of prochloraz, 32 g/kg of zinc sulfate, 55 g/kg of calcium chloride, 12 g/kg of ammonium molybdate, and 6 g/kg of manganese sulfate.

(6) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits, and further observe and screen them to obtain new varieties of macadamia nuts.

Example 5

A method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps:

(1) Selection of male parent: "Guire No. 1" was used as the female parent and "No. 695" as the male parent; the pollination site was located in Nanning, Guangxi; the soil was clay soil, the tillage layer was 25 cm, the soil contained 1.0% organic matter, and the soil pH was 4.5;

(2) Pre-treatment of macadamia nut parent:

2.1) Light control: Three months before the budding period of the flower spike, three-stage light control is carried out at night, and the starting time of light is 20:00 in the evening every day;

One stage of light control: the light time is controlled at 4h, the light intensity is controlled at 18Lux, and the duration of one stage of light is 25 days;

Two-stage lighting control: lighting time is controlled at 7h, light intensity is controlled at 27Lux, and the duration of the second stage lighting is 27 days;

Three-stage light control: the light duration is controlled at 4.5h, the light intensity is controlled at 42Lux, and the three-stage light duration lasts until the early flowering period;

2.2) Water control: 2 months before the budding stage of the flower spike, water the roots of the macadamia nut male plant once a week, and spray the entire plant with water until the stems and leaves of the male plant are all moist;

2.3) Spraying pre-treatment solution: 12 days before the inflorescence bud stage and during the inflorescence bud stage, spray the whole plant with pre-treatment solution until the stems and leaves of the male parent plant are completely wet; the pre-treatment solution uses water as a solvent and contains 48g/kg urea, 23g/kg boric acid, 14g/kg calcium gluconate, and 0.6mg/kg folic acid;

(3) Pretreatment of male parent pollen: After the male parent plant in step 2.3) blooms, collect pollen with a brush to obtain male parent pollen; dilute the pretreatment solution in step 2.3) by 60 times to obtain male parent pollen treatment solution; put the male parent pollen and the male parent pollen treatment solution into a finger-shaped tube together, with the amount of male parent pollen treatment solution per gram of pollen being 550 ml, and mix them evenly in the finger-shaped tube to obtain pollen to be irradiated and induced;

(4) Cesium-137 mutagenesis treatment: The pollen to be induced by radiation is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 8 Gy to obtain irradiated pollen;

(5) Pollination: Artificially emasculate the flowers of the mother plant, artificially pollinate the irradiated pollen, label the flowers, and thin out the fruits. During this period, the mother plant is managed in the field, pests and diseases are prevented and controlled in time, and sufficient water and fertilizer are ensured to ensure the normal development and maturity of the hybrid fruit.

(6) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits, and further observe and screen them to obtain new varieties of macadamia nuts.

Comparative Example 1

A method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps:

(1) Selection of male parent: "Guire No. 1" was used as the female parent and "No. 695" as the male parent; the pollination site was located in Nanning, Guangxi; the soil was clay soil, the tillage layer was 25 cm, the soil contained 1.0% organic matter, and the soil pH was 4.5;

(2) Pre-treatment of macadamia nut parent:

2.1) Water control: 2 months before the budding stage of the flower spike, water the roots of the macadamia nut male plant once a week, and spray the entire plant with water until the stems and leaves of the male plant are all moist;

2.2) Spraying pre-treatment solution: 12 days before the inflorescence bud stage and during the inflorescence bud stage, spray the whole plant with pre-treatment solution until the stems and leaves of the male parent plant are completely wet; the pre-treatment solution uses water as a solvent and contains 48g/kg urea, 23g/kg boric acid, 14g/kg calcium gluconate, and 0.6mg/kg folic acid;

(3) Pretreatment of male parent pollen: After the male parent plant in step 2.2) blooms, collect pollen with a brush to obtain male parent pollen; dilute the pretreatment solution in step 2.2) by 60 times to obtain male parent pollen treatment solution; put the male parent pollen and the male parent pollen treatment solution into a finger-shaped tube together, with the amount of male parent pollen treatment solution per gram of pollen being 550 ml, and mix them evenly in the finger-shaped tube to obtain pollen to be irradiated and induced;

(4) Cesium-137 mutagenesis treatment: The pollen to be induced by radiation is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 8 Gy to obtain irradiated pollen;

(5) Pollination: artificially emasculate the flowers of the female parent, artificially pollinate the irradiated pollen, label the flowers, and thin out the flowers and fruits. During this period, field management is carried out on the female parent plants, pests and diseases are promptly controlled, and sufficient water and fertility are ensured to ensure the normal development and maturity of the hybrid fruits. After the hybrid fruits have developed for 110 days, a hybrid fruit treatment liquid is sprayed until the outer surface of the hybrid fruits is completely wet. The hybrid fruit treatment liquid uses water as a solvent and contains 28 g/100 kg of prochloraz, 32 g/kg of zinc sulfate, 55 g/kg of calcium chloride, 12 g/kg of ammonium molybdate, and 6 g/kg of manganese sulfate.

(6) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits, and further observe and screen them to obtain new varieties of macadamia nuts.

Comparative Example 2

A method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps:

(1) Selection of male parent: "Guire No. 1" was selected as the female parent and "No. 695" as the male parent; the pollination site was located in Nanning, Guangxi; the soil was clay soil, the tillage layer was 25 cm, the soil contained 1.0% organic matter, and the soil pH was 4.5;

(2) Pre-treatment of macadamia nut parent:

2.1) Light control: Three months before the budding period of the flower spike, three-stage light control is carried out at night, and the starting time of light is 20:00 in the evening every day;

One stage of light control: the light time is controlled at 4h, the light intensity is controlled at 18Lux, and the duration of one stage of light is 25 days;

Two-stage lighting control: lighting time is controlled at 7h, light intensity is controlled at 27Lux, and the duration of the second stage lighting is 27 days;

Three-stage light control: the light duration is controlled at 4.5h, the light intensity is controlled at 42Lux, and the three-stage light duration lasts until the early flowering period;

2.2) Water control: 2 months before the budding stage of the flower spike, water the roots of the macadamia nut male plant once a week, and spray the entire plant with water until the stems and leaves of the male plant are all moist;

(3) Pretreatment of male parent pollen: After the male parent plant blooms, collect pollen with a brush to obtain male parent pollen; place the male parent pollen in a finger-shaped tube to obtain pollen to be irradiated and induced;

(4) Cesium-137 mutagenesis treatment: The pollen to be induced by radiation is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 8 Gy to obtain irradiated pollen;

(5) Pollination: artificially emasculate the flowers of the female parent, artificially pollinate the irradiated pollen, label the flowers, and thin out the flowers and fruits. During this period, field management is carried out on the female parent plants, pests and diseases are promptly controlled, and sufficient water and fertility are ensured to ensure the normal development and maturity of the hybrid fruits. After the hybrid fruits have developed for 110 days, a hybrid fruit treatment liquid is sprayed until the outer surface of the hybrid fruits is completely wet. The hybrid fruit treatment liquid uses water as a solvent and contains 28 g/100 kg of prochloraz, 32 g/kg of zinc sulfate, 55 g/kg of calcium chloride, 12 g/kg of ammonium molybdate, and 6 g/kg of manganese sulfate.

(6) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits, and further observe and screen them to obtain new varieties of macadamia nuts.

Comparative Example 3

A method for creating new germplasm by hybridization of macadamia nuts and cesium radiation, comprising the following steps:

(1) Selection of male parent: "Guire No. 1" was used as the female parent and "No. 695" as the male parent; the pollination site was located in Nanning, Guangxi; the soil was clay soil, the tillage layer was 25 cm, the soil contained 1.0% organic matter, and the soil pH was 4.5;

(2) Pretreatment of male parent pollen: After the male parent plant blooms, collect pollen with a brush to obtain male parent pollen; place the male parent pollen in a finger-shaped tube to obtain pollen to be irradiated and induced;

(3) Cesium-137 mutagenesis treatment: The pollen to be induced by radiation is irradiated with ¹³⁷ Cs-γ rays at an irradiation dose rate of 0.75 Gy/min and an irradiation dose intensity of 8 Gy to obtain irradiated pollen;

(4) Pollination: artificially emasculate the flowers of the female parent, artificially pollinate the irradiated pollen, label the flowers, and thin out the flowers and fruits. During this period, field management is carried out on the female parent plants, pests and diseases are promptly controlled, and sufficient water and fertility are ensured to ensure the normal development and maturity of the hybrid fruits. After the hybrid fruits have developed for 110 days, hybrid fruit treatment liquid is sprayed until the outer surface of the hybrid fruits is completely wet. The hybrid fruit treatment liquid uses water as a solvent and contains 28 g/100 kg of prochloraz, 32 g/kg of zinc sulfate, 55 g/kg of calcium chloride, 12 g/kg of ammonium molybdate, and 6 g/kg of manganese sulfate.

(5) Harvesting and selection: When the hybrid fruits mature, harvest them and record their shapes; sow the hybrid fruits and further observe and screen them to obtain new varieties of macadamia nuts.

The results of the hybrid breeding experiments in Examples 1-5 and Comparative Examples 1-3 are shown in Table 2 below:

Table 2

The hybrid fruits obtained by processing in Examples 1-5 and Comparative Examples 1-3 were subjected to selection experiments:

1. Germination test:

1) Place the seeds on the germination bed, cover with a thin layer of soil, water them every day, wait for the seeds to germinate, and calculate the germination rate. Germination rate (%) = (normal germination number/experimental seed number) x 100%;

2) After about 5 weeks, when the seeds have germinated evenly, choose a cloudy day to transplant the seedlings into a 18cm*18cm seedling cup and cover the transplanted seedlings with a shade net; the formula of the nutrient soil in the seedling cup is a mixture of soil, organic fertilizer, decomposed pig manure, and river sand in a volume ratio of 5:1:2:1;

3) Observe the morphology of seedlings from February to December, observe special traits, such as plant branch color variation, leaf deformity, and tree shape variation of young trees, collect statistics on special traits, and calculate the distortion rate;

Table 1 below gives the germination rate results of the hybrid fruits in Examples 1-5 and Comparative Examples 1-3 after seeding and the selection results are shown in Table 3 below;

table 3

From the above experimental results, it can be seen that the method of creating new germplasm by hybridization of macadamia nuts and cesium radiation of the present invention first selects macadamia nut male parent varieties whose data such as the number of pollinated flowers, average fruit bearing value, fruit setting rate, and fruit setting rate are much higher than those of the control group under natural artificial pollination conditions, so as to facilitate subsequent artificial pollination experiments; the macadamia nut male parent is subjected to three-stage light control, water control, and spraying of pretreatment liquid, and the male parent pollen is pretreated at the same time, so that the pollen can adapt to light radiation in advance, enhance the adaptability of the pollen to cesium-137 ray irradiation, reduce the sensitivity of the pollen to cesium-137 ray irradiation, and increase the semi-lethal irradiation amount of the pollen, thereby promoting irradiation mutagenesis of macadamia nut pollen. The combination of three-stage light control, cesium-137 ray irradiation, and spraying of pre-treatment liquid can also further accelerate the mutation speed of macadamia seeds and increase the mutation rate, thereby obtaining new varieties of macadamia nuts; the pre-treatment liquid also includes folic acid, which can be directly absorbed and utilized by female flowers, making the female flowers more pollinated and the fruit setting rate higher; spraying hybrid fruit treatment liquid, the myclobutanil in the hybrid fruit treatment liquid mainly prevents and controls the occurrence of fruit diseases. The hybrid fruit treatment liquid can also supplement zinc, calcium, molybdenum, manganese and other elements for macadamia plants, which can avoid the lack of zinc, calcium, molybdenum, manganese and other elements in the fruit, root system, and leaves caused by continuous high temperature, avoid premature fruit drop, and is beneficial to the acquisition of new varieties of macadamia nuts.

Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, these modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims (10)

1. A method for creating a new germplasm by hybridization of macadimia nuts and cesium radiation, comprising the following steps:

(1) Male parent selection: taking Guifei No. 1 as a female parent and Australian nuts of other varieties as male parents, respectively carrying out artificial pollination experiments, and selecting the varieties with good pollination effect and high fruit setting rate as the Australian nut male parents;

(2) Pretreatment of macadimia nut male parent:

2.1 Lighting control: 3 months before the bud stage of the flower ears, three sections of illumination control are carried out at night;

And (3) controlling the illumination: the illumination time is controlled to be 3-5 h, the illumination intensity is controlled to be 15-20 Lux, and the illumination duration is one period: 20-30 days;

two-stage illumination control: the illumination time is controlled to be 6-8 h, the illumination intensity is controlled to be 25-30 Lux, and the two-stage illumination duration is as follows: 20-30 days;

Three-section illumination control: the illumination time is controlled to be 4-6 h, the illumination intensity is controlled to be 40-45 Lux, and the three-period illumination time lasts until the initial flowering period;

2.2 Water control: watering the roots of male parent of Australian nuts once every week 2 months before the bud period of the flower ears, and spraying water to the whole plant until the stems and leaves of the male parent plant are all moist;

2.3 Spraying pretreatment liquid: spraying the pretreatment liquid to the whole plant until the stems and leaves of the male parent plant are all wet 10-15 days before the bud stage of the flower spike; the pretreatment liquid takes water as a solvent and contains urea with the concentration of 45-50 g/kg, boric acid with the concentration of 20-25 g/kg and calcium gluconate with the concentration of 10-15 g/kg;

(3) Pretreatment of male parent pollen: flowering the male parent plant in the step 2.3), and taking pollen to obtain male parent pollen; diluting the pretreatment liquid in the step 2.3) by 50-70 times to obtain a male parent pollen treatment liquid; putting the male parent pollen into the male parent pollen treatment liquid, and uniformly mixing to obtain pollen to be subjected to radiation mutagenesis;

(4) Cesium-137 mutagenesis treatment: treating pollen to be subjected to radiation mutagenesis by using ¹³⁷ Cs-gamma rays, wherein the irradiation dose rate is 0.75Gy/min, and the irradiation dose intensity is 5-10 Gy, so as to obtain irradiated pollen;

(5) Pollination: artificial pollination is carried out on the pollen subjected to the irradiation treatment, and flower and fruit thinning is carried out;

(6) Collecting the selection: harvesting the hybrid fruits after the hybrid fruits develop and mature, and recording the shapes of the hybrid fruits; sowing the hybrid fruits, and further observing and screening to obtain the novel macadimia nut variety.

2. The method of claim 1, wherein the macadamia nut male parent in step (1) is 695 variety.

3. The method for creating new germplasm by hybridization of macadamia nut and cesium radiation according to claim 1, characterized in that, in the step 2.1), three-stage illumination control is performed at night 3 months before the bud phase of the flower spike;

and (3) controlling the illumination: the illumination time is controlled to be 4-5 h, the illumination intensity is controlled to be 18-20 Lux, and the illumination duration is one period: 25-30 days;

Two-stage illumination control: the illumination time is controlled to be 7-8 h, the illumination intensity is controlled to be 27-30 Lux, and the two-stage illumination duration is as follows: 27-30 days;

three-section illumination control: the illumination time is controlled to be 4.5-6 h, the illumination intensity is controlled to be 42-45 Lux, and the three-period illumination time lasts until the initial flowering period.

4. The method of claim 1, wherein the three-stage illumination control in step 2.1) is performed with a daily illumination initiation time of 20 hours in the evening.

5. The method for creating new germplasm by hybridization of macadimia nut and cesium radiation according to claim 1, characterized in that in the step 2.3), the pretreatment liquid takes water as a solvent and contains urea with the concentration of 48-50 g/kg, boric acid with the concentration of 23-25 g/kg and calcium gluconate with the concentration of 14-15 g/kg.

6. The method of claim 1, wherein the pretreatment liquid in step 2.3) further comprises folic acid at a concentration of 0.5-0.8 mg/kg.

7. The method for creating new germplasm by hybridization of macadimia nut and cesium radiation according to claim 1, characterized in that the pretreatment liquid in the step (3) is diluted 65-70 times to obtain a male parent pollen treatment liquid; the dosage of the pollen treatment liquid for the male parent is 500-600 ml/g pollen.

8. The method for creating new germplasm by hybridization of macadimia nut and cesium radiation according to claim 1, characterized in that the pollen to be subjected to radiation mutagenesis is subjected to radiation treatment by ¹³⁷ Cs-gamma rays in the step (4), the radiation dosage rate is 0.75Gy/min, and the radiation dosage intensity is 8-10 Gy, so that the radiation-treated pollen is obtained.

9. The method for creating new germplasm by hybridization of macadimia nut and cesium radiation according to claim 1, characterized in that in the step (5), the hybridization fruits are developed for 100-120 days, a hybridization fruit treatment liquid is sprayed until the outer surfaces of the hybridization fruits are completely wetted, and the hybridization fruit treatment liquid takes water as a solvent, and contains prochloraz with the concentration of 25-30 g/100kg, zinc sulfate with the concentration of 30-35 g/kg, calcium chloride with the concentration of 50-65 g/kg, ammonium molybdate with the concentration of 10-15 g/kg and manganese sulfate with the concentration of 5-8 g/kg.

10. The method for creating new germplasm by hybridization of macadamia nut and cesium radiation according to claim 9, characterized in that in the step (5), the hybridization fruit is developed for 110-120 days, a hybridization fruit treatment liquid is sprayed until the outer surface of the hybridization fruit is completely wetted, and the hybridization fruit treatment liquid takes water as a solvent, and contains prochloraz with the concentration of 28-30 g/100kg, zinc sulfate with the concentration of 32-35 g/kg, calcium chloride with the concentration of 55-65 g/kg, ammonium molybdate with the concentration of 12-15 g/kg and manganese sulfate with the concentration of 6-8 g/kg.