CN110881326A - Grafting method for improving cold resistance and drought resistance of hybrid hazel - Google Patents

Abstract

The invention belongs to the technical field of planting, and particularly provides a grafting method for improving the cold resistance and drought resistance of hybrid hazel in Pingyou. The grafting method for improving the cold resistance and drought resistance of the hybrid hazel in Pingyou has the advantages that the survival rate is about 85 percent generally, the hybrid hazel variety can be promoted to grow well, is cold-resistant, drought-resistant and long in growth life, and the hybrid hazel variety can be enabled to bear fruits in advance and enter a high-yield period as soon as possible.

Description

Grafting method for improving cold resistance and drought resistance of hybrid hazel

Technical Field

The invention belongs to the technical field of planting, particularly relates to a plant asexual propagation method, and more particularly relates to a grafting method for improving cold resistance and drought resistance of hybrid hazel of Pingyou.

Background

First, the important significance of hazelnut industry development

Hazelnuts are an important nut and woody oil tree species in the world. The hazelnut kernel can be eaten raw or fried, has good flavor and high heat, and is a high-quality raw material for processing foods such as chocolate, candy, cake and the like in the food industry; the hazelnut is also the raw material for squeezing edible oil and various industrial oils, the oil content is 2-3 times of soybean, the hazelnut can be used as medicine, and the oil meal can be used as feed or fertilizer. The hazelnut shell is a raw material for preparing active carbon. The bark and fruit bud contain tannin (8.5% -14.5%), and can be used for preparing tanning substance and baking gum, and the leaf of hazel can be used for silkworm breeding. The wood can be used for making walking sticks, umbrella handles and the like.

Globally, turkey accounts for two thirds of the world's hazelnut production, and hazelnuts bring about 12% of foreign trade sales to the country's economy, with major producing countries including spain, italy, and the united states. The planting history of the hazelnuts in China is long, but the artificial cultivation of the hazelnuts and the hazelnuts is not carried out, most of the hazelnuts are wild, the hazelnuts are always in a wild state, the yield of the hazelnuts is low, the hazelnuts are not exported all the time due to low quality and yield of the hazelnuts, on the contrary, foreign hazelnuts are more and more brought into the market of China, and if the exported hazelnuts of the whole turkey are all exported to China, the market requirements of China still cannot be met.

The hazel nut kernel contains a plurality of vitamins, minerals and amino acids, the content of dietary fiber is very rich, and simultaneously contains taxol with anticancer effect and β -sitosterol for promoting the degradation and metabolism of cholesterol in human bodies.

Problems in the production of hybrid hazelnuts

The hybrid hazelnuts in Ping-Europe can be planted in the northern and the three northern areas of yellow river in China within the range of 42 degrees of northern latitude. In recent years, hybrid hazelnuts in Pingyou have been developed in large areas, and have been expanded at a rate of approximately 20 ten thousand mu per year, and the following problems have arisen with the expansion of popularization areas: the hybrid hazelnuts and hazelnuts in Pingyou are shrubs and have shallow root systems, and the root systems in the wintering period are affected by freezing and water absorption to cause early spring strip drawing; a great amount of manpower is needed to remove the tillering from the base part for maintaining the single-stem tree form; green plant layering is mostly adopted, and the propagation coefficient is low. The details are as follows:

a. the root system is shallow-the cultivated hazel tree in China is hybrid hazel in Ping Europe, the hybrid hazel tree is determined by the shrub characteristic, the hybrid hazel tree is a shallow root tree species, the root system is intensively distributed in a soil layer of 0-50cm underground, and the hybrid hazel tree is not drought-resistant. When the soil moisture condition is poor and the duration is long and the soil moisture reaches below the critical point born by the root system, the phenomena of branch draining and tree body draining are generated.

b. Freezing damage and strip drawing- -although some cold-resistant varieties in the hybrid hazelnuts of Pingguo can resist low temperature of about-40 ℃ in the dormancy stage, the problems of freezing damage, male inflorescence freeze-drying, strip drawing and the like occur occasionally. The freeze injury comprises branch freeze injury and flower freeze injury, the branch freeze injury can cause xylem and medulla to be browned and dead, but direct branch freeze injury is rare. In winter, in the years or areas with less snow and dry air, the phenomenon that male inflorescences are drained is common, and the drained male inflorescences cannot bloom and loose pollen, so that pollination and fruit setting are influenced.

c. Drought resistance problem- -hybrid hazel of Pingguo is a tree species with shallow root, and the normal growth, development and fructification of tree bodies can be ensured only if soil keeps a certain water content. If the precipitation is less and the drought year occurs, the branches are short in growth, the leaves are small, the leaf edges are scorched, the fruit drop is serious, the fruit bearing is less, and the quality of the nuts is reduced due to drought.

The hybrid hazel has a tree structure, different from most fruit trees, is shrub, has the characteristics of having rhizomes, germinating a large amount of tillering and root breeding from a base part every year in a growing season, competing for nutrition and moisture, and needing to be removed in time in order to ensure that the hazel is normally developed and fruited, is not beneficial to field management and fruit harvesting, and needs to consume a large amount of manpower. The research shows that the single-trunk tree form has higher single fruit weight and single kernel weight and is suitable for David, Yuzhu and other big crown tree varieties. The single-stem tree forms adopted in the prior production all need a large amount of manpower to remove the tillering, and if arbor tree species without tillering are adopted as stocks, the single-stem tree forms can be constructed in a labor-saving and time-saving manner.

e clonal propagation problem-compared with green plant layering, the grafting propagation has the characteristic of high propagation coefficient, but the biggest problem of the prior method for cultivating and propagating the filbert grafting is lack of proper rootstock in popularization and application, and the seedling-cultivated corylus heterophylla seedlings are not suitable for being used as the rootstock for cultivating filbert commodities due to the strong tillering capability and the phenomenon of petiolus.

Thirdly, the adaptability problem of hybrid planting in Ping-Europe needs to be improved by improving root system

The root system not only holds the huge overground part of the plant in the soil, but also maintains the substances and energy required by each life activity by absorbing water and nutrient resources in the soil environment for the overground part to utilize. At present, the shallow root system of hybrid hazelnuts in Pingyou causes the problems of freezing damage and drought in different regions and under individual extreme climatic conditions, the low temperature is low in the overwintering period, the water absorption is influenced by the frozen root system, the moisture of branches is greatly dissipated in drought and windy branches in early spring, the branches cannot be rehydrated and taken out, the safe overwintering of plants depends on the water holding capacity of tissues, and the growth state of the root system is dominant because the distribution of the root system influences the water absorption capacity of the root system in the overwintering period. The production needs to improve the adaptability of hybrid planting in Pingguo by improving the root system.

Fourthly, the problem that the hybrid hazelnuts in Pink Europe are easy to be frozen and stripped and the like is solved by utilizing the characteristic of developed root system of the hazelnut trees

The hazel is a tree, is a special rare and precious tree species in China, is naturally distributed in wet hillside forests with elevation of 2000-3500m in southwest of Sichuan and Yunnan, and has an average slope of 35 degrees in a negative slope (with the north slope upward). Nowadays, the hazel grows in Henan, Shaanxi, Gansu, Hubei, Hunan, Guizhou, Zhejiang and other provinces. The hazel has delicious taste and edible kernel, beautiful wood texture and color, easy processing and carving, wide application in the wood processing field, excellent fruit and wood dual-purpose tree species and great development value.

The hazel can still grow robustly in the mountainous area at a low temperature of-23 ℃, and has strong drought resistance, heat resistance, water flooding resistance, cold resistance, pruning resistance, less plant diseases and insect pests and developed root system. Is a good material for cultivating arbor-shaped single-stem tree-shaped hazel tree varieties and rootless breeding stocks. The method is characterized in that the hybrid hazelnuts in Pink Europe are grafted on the hazelnuts, the problems of easy freezing damage, stripping, drought stress and the like caused by shallow root systems of the hybrid hazelnuts in Pink Europe are solved by utilizing the characteristics of arbor of the hazelnuts and the special stress resistance of the hazelnuts, and the construction of a labor-saving single-stem tree-shaped structure is facilitated.

At present, the rootstocks for grafting hybrid hazelnuts in Pink-Europe are mostly Pink-Hazel or Pink-Europe hybrid hazelnuts, however, because the tillering capacity is too strong and the phenomena of pettitoes exist, the Pink-Hazel or Pink-Europe hybrid hazelnuts are not suitable for being used as the rootstocks for cultivating hazel varieties.

The grafting advantages of the hazel as the stock are as follows: the corylus heterophylla is a rare tall tree in corylus, has no root tiller, upright trunk, vigorous growth and no disease and insect damage, can lead the corylus heterophylla variety to bear fruits in advance and enter a high yield stage as soon as possible, and is a good tree material for cultivating single-stem tree-shaped corylus heterophylla varieties and root tillering stocks.

Disclosure of Invention

The invention aims to provide a grafting method for improving the cold resistance and drought resistance of hybrid hazel of Pingyou aiming at the problem that the cold resistance and drought resistance of hybrid hazel of Pingyou in the prior art are not strong enough, and the grafting method is to graft the hybrid hazel of Pingyou by taking the hazel of Hua as a rootstock of the hybrid hazel of Pingyou.

The invention relates to a grafting method for improving the cold resistance and drought resistance of hybrid hazel, which comprises the following steps:

a, collecting, shelling, sowing and seedling management of hazel seeds;

collecting and storing B Ping European hybrid hazel scions;

and C, selecting a hazel rootstock for grafting.

Wherein, the collection of A is to collect seeds when fruits are ripe in the middle of 8 months every year.

And the husking is to manually or mechanically remove the shells of the hazelnut seeds and then collect the good seeds sinking to the water bottom by a water separation method for later use.

Wherein, the sowing step A is to sow the collected hazel seeds in autumn in the current year or sow the hazel seeds in spring from sand storage to the next year.

The autumn sowing is direct sowing after seed soaking for 2 days, the sowing depth is 6-8cm, the soil is covered with 3-5cm, the soil moisture is preserved, and the seedlings gradually emerge in the spring of the next year along with the rise of the air temperature.

The hazel seeds are subjected to sand storage treatment until the next year, the sand is wet, a pit is dug in a leeward and sunny place, then a layer of seeds are buried with the sand layer by layer, and the sand is kept wet and breathable in the period; sowing can be carried out after 60% -80% of the seed cracks germinate in 3 months in spring next year, the sowing depth is 6cm-8cm, and 3-5cm of soil is covered on the seeds.

And the seedling management of the step A comprises timely weeding, killing insects (mainly cutworms), fertilizing and watering.

Wherein, the collection of B is to select the annual branches which grow robustly at the periphery of the crown of the European hybrid hazel nut tree, cut off the thin and weak part at the top and the part with thin and small bud bodies at the base, only leave the part containing 1-2 full buds in the middle section of the branches as the scion, bundle each 20-50 branches with the thickness of 0.7-0.9cm and the length of 5-7cm, and hang the variety label.

Wherein, the storage of B is divided into long-term storage and short-term storage (less than one week).

The long-time storage is that the sand is buried by wet sand in a temporary planting ditch, a storage cellar or a constant-temperature air-conditioned cold store, the humidity of the sand is measured by hand-holding the sand into a ball without dripping water, and the storage temperature is not more than 1 ℃.

The short-term storage is that the product is wrapped by plastic film and placed in a cool place with shady back.

And C, selecting the rootstocks, selecting strong corylus heterophylla seedlings growing for 1-2 years as the rootstocks, wherein the base diameter of the rootstocks reaches more than 0.8cm, and the rootstocks are free from diseases, insect pests and mechanical damage.

And C, grafting for 3 months, 12 days to 4 months and 5 days.

C, grafting the 1-2 year old corylus heterophylla seedling stock by adopting a method with wood budding, trimming the root system of the selected stock, wherein the trimming length of the root system is about 7cm, then cutting the stock seedling at the position with the trunk height of 15cm, cutting off the bark by 2-3cm, and flattening; selecting bud slices on the scion according to the stock, cutting off the bud slices on the scion by using a grafting knife, flattening the bud slices, then pasting the bud slices on the cut surface of the stock, aligning the pasting surface, and tightly binding the bud slices by using plastic films with the width of 1.5cm and the length of 25-30cm to expose the bud part of the tree.

The grafting method for improving the cold resistance and drought resistance of hybrid hazel in Pingyou comprises the following steps:

d, managing grafted seedlings;

e, outplanting and storing the nursery stock.

The invention also provides application of the grafting method for improving the cold resistance and drought resistance of the hybrid hazel of Pink Europe in breeding of the hybrid hazel of Pink Europe.

The grafting method for improving the cold resistance and drought resistance of the hybrid hazel can promote the hybrid hazel variety to have good growth vigor, severe cold resistance, drought resistance and long growth life, and can lead the hybrid hazel variety to bear fruits in advance and enter a high-yield period as soon as possible.

Detailed Description

The following examples further illustrate the present invention but are not to be construed as limiting the invention. Modifications or substitutions to methods, procedures, or conditions of the invention may be made without departing from the spirit and scope of the invention.

Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

Example 1

The embodiment of the grafting method for improving the cold resistance and drought resistance of hybrid hazelnuts in Pingyou comprises the following steps:

collecting, shelling, sowing and seedling stage management of A-Hua hazel seeds

(1) Harvesting of seeds

Corylus avellana is a tree species of big trees growing in mountains with an altitude of about 700 m. Good growth vigor, cold resistance, drought resistance and long growth life. The fruit is collected in the middle of 8 months each year when it is ripe.

(2) Seed dehulling treatment

The picked fruit is manually hulled to separate it, or mechanically hulled. The seeds which are settled on the water bottom by the water separation method are all good seeds, and then the seeds are collected for sowing.

(3) Seeding

If the land where the grains are harvested in the current year can be sowed in autumn, the seeds screened out can be sowed directly after being soaked for 2 days. Sowing depth is 6-8cm, covering soil about 4cm above the seeds, preserving soil moisture, and gradually growing seedlings along with the rise of air temperature in spring of the next year. The seeds can be sown in 3 months in the spring of the next year, but the seeds are subjected to sand storage treatment, sand is wet, a pit is dug in a leeward and sunny place, then a layer of seeds is buried with sand layer by layer, and the sand is kept wet and breathable in the period. 60% -80% of the seed cracks can be sown after germination in the next 3 months.

(4) Management of seedling stage

When the seedling stage is reached, weeding, killing insects (mainly cutworms), applying fertilizer and watering are carried out in time. And selecting healthy and strong seedlings for grafting in 3 months in the next year.

Collecting and storing B Ping European hybrid hazel scion

The scion source is the strong plant without plant diseases and insect pests of the fine variety examined by the fine variety of the forest as the scion stock tree. The part of the improved hybrid hazel variety (scion used in this example) that is currently examined by the improved variety of trees is specifically shown in table 1:

TABLE 1 partial Pinou hybrid hazel improved variety examined by forest improved variety

Name of breed	Breeding unit	Authority unit	Year of examination
				Dawei tea	Research institute of economic forest of Liaoning province	Liaoning province forest fine variety approval committee	1999
Jade pendant	Research institute of economic forest of Liaoning province	Liaoning province forest fine variety approval committee	1999
				Liaohazel No. 3	Research institute of economic forest of Liaoning province	Liaoning province forest fine variety approval committee	2006
Liaohazel No. 4	Research institute of economic forest of Liaoning province	Liaoning province forest fine variety approval committee	2006
				Liaohazel No. 7	Research institute of economic forest of Liaoning province	Liaoning province forest fine variety approval committee	2013
Liaohazel No. 8	Research institute of economic forest of Liaoning province	Liaoning province forest fine variety approval committee	2013
				Liaohazel No. 9	Research institute of economic forest of Liaoning province	Liaoning province forest fine variety approval committee	2013

Selecting annual branches which grow robustly on the periphery of the crown of the mother tree in the hybrid hazel variety garden in Ping Europe, cutting off thin and weak parts at the top and thin and small parts of buds at the base, only keeping parts containing 1-2 full buds in the middle sections of the branches as scions, bundling 20-50 branches into bundles with the thickness of 0.7-0.9cm and the length of 5-7cm, and hanging variety labels. When the storage time of the scion is longer, the scion can be buried in a temporary planting ditch, a storage cellar or a constant-temperature air-conditioned cold store by using wet river sand, the humidity of the river sand is measured by hand-holding the scion into a ball without dripping water, and the storage temperature is not more than 1 ℃. The cion can be stored for a short time (within one week) and tightly wrapped by a plastic film and placed in a cool place with shady back.

C selecting stock for grafting

The grafting time is 3 months and 12 days to 4 months and 5 days.

Rootstock selection

The strong corylus heterophylla seedlings growing in 1-2 years in the nursery is selected as the rootstocks, the diameter of the rootstocks reaches more than 0.8cm, and the rootstocks do not have diseases, insect pests and mechanical damage. And (4) carrying out root system pruning on the selected stock, wherein the pruning length of the root system is about 7cm, and then shearing the stock seedling at the position with the trunk height of 15 cm.

Grafting

At present, the grafting method of hybrid hazelnuts by Pingyou mainly comprises root grafting, grafting (including cleft grafting and cutting grafting) and budding (including T-shaped budding and budding with wood).

(1) The subcutaneous grafting method comprises the following steps:

is mostly used for relatively thick rootstocks (the diameter of the 3-5 year old basal part is preferably more than 0.8-2 cm). The scion can adopt annual vegetative branches or 2-3 annual secondary branches with 2-3 fruiting mother branches, the splicing length is about 15cm, and the upper end of the scion is 0.5 cm from the fruiting mother branch or the normal bud and is cut flat. The lower end of the fruit bearing mother branch or the front bud is downwards cut into an inclined plane with the length of about 3cm from the lower part of the back of the fruit bearing mother branch or the front bud. The opposite side is cut off its surface to form a small bevel; selecting the smooth side of the bark of the cut rootstock, vertically cutting the cortex to the xylem by a knife, wherein the length is about 3cm, and then stripping off the rootstock incision for insertion. Aiming at aligning the cambium of the scion bevel with the cambium of the stock, the tip end is aligned with the cutting seam, and the fingers press the cut of the stock tightly and are slowly inserted. The cut surface of the scion is slightly exposed out of the connector, and the connector and the cut opening of the stock are tightly bound by a plastic film belt with the width of about 3.3 centimeters (1 inch), and can be covered by low grafting buried soil, and the high grafting can be sleeved by the plastic film.

(2) The cleft grafting method comprises the following steps:

the method can be applied regardless of the thickness of the rootstock, but is preferably applied to a large rootstock with a diameter of more than 1.5 cm. The rootstock is thin and thick, and only one scion is used, and 2-4 scions can be used. The cut stock is longitudinally cut into a slit from the center, and the thick stock can be cut into a cross shape. The length and cutting method of the scion is substantially the same as that of the subcutaneous tissue, but both sides of the lower end are cut into 3cm long inclined planes. The fine scion inclined plane should be short, while the coarse scion has a slightly longer bevel. Then the stock is inserted into the cutting of the stock, if the stock is thick, the scion is needed to be inserted into the side of the scion which is tightly tied, so that the cambium layers of the stock and the scion are mutually tightly connected. After the rootstocks are grafted for a short time, the rootstocks need to be bound and finally sleeved with plastic bags or buried in soil.

(3) The method for the bud grafting comprises the following steps:

bud grafting (embedded bud grafting) with xylem, namely taking the current-year young shoots, and downwards cutting the shoots into the xylem at an angle of 15-25 degrees at a position 1cm above the buds, wherein the cut length is about 2 cm. And cutting the wood part at an angle of 20-30 degrees at a position 1.5cm below the bud, intersecting with the previous cut, and taking off the wood bud piece. Cutting the stock at the position 3-5cm away from the ground surface in the southwest direction, wherein the shape, length and thickness of the stock are the same as the state of the scion after bud cutting. The bud slices are embedded into the cuts of the rootstocks, one side or two sides of the bud slices are aligned, and the lower ends of the bud slices are aligned. The connecting bud is tightly bound by a plastic strip.

(4) The T-shaped budding method comprises the following steps:

budding without xylem (T-shaped budding) -taking the current new shoot, crosscutting a knife at a position about 3-4 cm above the bud body, and penetrating into the xylem by 1.5-2 mm; and then, the bud pieces are cut upwards from the positions 5-6mm below the petioles, the transverse cuts above the axillary buds are cut, the cutter is stopped, then the shield-shaped bud pieces are taken down, and the xylem in the bud pieces is pinched off by using nails, so that the bud pieces are immediately moisturized in the mouth. The cortex layers on the two sides of the cut of the stock are slightly stripped by a tool tip, the cut bud slices are inserted into the cut of the stock, the upper ends of the bud slices are tightly connected with the transverse cut of the stock, and the bud slices are tightly bound by a plastic film.

The invention adopts a method with wood bud grafting to carry out grafting. Preparing a plastic film strip for binding. The thin and thick flexible plastic film is cut into strips with the width of 1.5cm and the length of 25-30cm, and the strips are arranged and bundled for standby. Selecting a hazel rootstock, cutting off the bark of the hazel rootstock by 2-3cm by using a grafting knife, and flattening; selecting bud slices on the scion according to the stock, cutting off the bud slices on the scion by using a grafting knife, flattening the bud slices, then pasting the bud slices on the cut surface of the stock, aligning the veneering, and tightly binding by using a binding strip to expose the bud part of the tree. The bud slice gradually survives after 7-10 days. The general survival rate is about 85 percent (except for special weather).

D grafted seedling management

The grafted nursery stock is planted in a greenhouse or a greenhouse on the same day, the row spacing of the nursery stock is 20cm multiplied by 50cm, the planting depth is 6-10cm of root system burying depth, and proper watering is needed before planting in order to prevent the watered soil from sinking too much and causing difficulty in mastering the planting depth.

(1) Temperature control

The highest temperature in the greenhouse or the greenhouse in the daytime is not more than 25 ℃, when the temperature is close to 25 ℃, the air is released in time to cool, the lowest temperature at night is not less than 5 ℃, and heat preservation or heating measures are taken when necessary. When the lowest temperature of the open field is stabilized to be above 15 ℃, the plastic film of the greenhouse or the shed needs to be removed in time so as to ensure that the grafted seedlings grow robustly under the condition of sufficient illumination.

(2) Moisture management

Before the plastic film of the greenhouse or the shed is removed, the plastic film is watered thoroughly every 7 days, and after the plastic film is removed, the water is watered at proper time according to the conditions of natural precipitation and soil moisture content.

(3) Weeding

Adopts an artificial weeding mode to weed in time, and prevents weeds from causing adverse effects on the growth of seedlings.

(4) Bud picking, sprout removing and binding strip removing

a. And (3) timely removing sprouts and sprouts on the rootstocks after grafting.

b. Removing the binding strip. After the grafting survives, the binding strips can be gradually removed when the branches grow to be 20-30cm high, and the situation that the bud slices are lifted up and withered to die due to the early removal of the binding strips is avoided.

(5) Pest control

The main disease is powdery mildew, and 20 percent triazolone missible oil 800 solution is sprayed once in the early stage of the disease; the main insect pests include aphids, red spiders and the like, all the insect pests are subjected to medicament control at the initial stage of occurrence, 2000 times of liquid of 10% imidacloprid wettable powder is used for controlling the aphids, and 1000 times of liquid of 25% azocyclotin wettable powder is used for controlling the red spiders. The use of pesticides is carried out according to GB 4285 and GB/T8321.

E, outplanting and storing the nursery stock.

(1) Out of nursery period

The seedling in autumn of the current year naturally falls to the next year before sprouting.

(2) Grade and grading standard of nursery stock

Special-grade seedlings: the height of the seedling is more than 110cm, the joint healing is good, and no plant diseases, insect pests and mechanical damage exist.

First-stage seedling: the height of the seedling is more than 80cm, the joint healing is good, and no plant diseases, insect pests and mechanical damage exist.

Second-stage seedling: the height of the seedling is more than 60cm, the joint healing is good, and no plant diseases, insect pests and mechanical damage exist.

And (3) waiting for outer seedlings: any index which can not reach the standard of the secondary seedlings is equal-outside seedlings which can not be sold out of the nursery.

(3) Stock storage

And adopting a temporary planting mode of a temporary planting groove for storage. The depth of the temporary planting ditch is 1m, and the width and the length are determined according to the size of the land and the number of the seedlings needing temporary planting. And selecting dry land parcels with leeward and relatively high topography in the temporary planting place, and avoiding temporary planting of seedlings in wind ports and low-lying places. When in temporary planting, clean river sand is selected as a substrate, 1 bundle of selected and graded nursery stocks is formed by beating 10 plants, labels are hung, varieties, quantity and grades are marked, the bundle is placed in a temporary planting ditch, an included angle of 60 degrees is formed between the bundle and the ground, the root system of the nursery stocks needs to be fully buried by wet sand and cannot be suspended in the air, otherwise, the dry and mildewed root system can be caused. The humidity of the sand is generally required to be that the sand is held by hands to be agglomerated and is loosened when the hands are loosened, and the sand is not dripped. The height of the buried sand of the seedling stem at least reaches 50cm, and the upper part of the seedling stem is covered by grass curtains or heat preservation cotton quilts and other materials to prevent dehydration and drainage.

Example 2

The key factors for ensuring the survival rate of the grafted seedlings are the grafting time selection, temperature control, scion preservation and grafting technology, and the following experiments are carried out for optimizing technical parameters:

in 2016, the influence of different grafting periods and grafting methods on the survival rate of the corylus heterophylla hybrid corylus heterophylla grafted by taking corylus heterophylla as the rootstock is compared, and the result is shown in table 2.

TABLE 2 grafting survival rates at different periods and methods

Time period	Method of producing a composite material	Grafting tree	Number of surviving plants	Survival rate/%
					3 month and 20 days	T-shaped bud grafting	850	700	82.35％
4 month and 3 days	Bud grafting with wood	901	859	95.34％
					8 month and 18 days	T-shaped bud grafting	267	3	1.12％
9 month and 19 days	Bud grafting with wood	278	38	13.67％

In order to verify the experimental results of different grafting methods, comparative experiments of grafting methods of grafting corylus heterophylla hybrid corylus heterophylla by taking corylus heterophylla as a rootstock were carried out again in 2017, and the results are shown in table 3.

TABLE 3 grafting survival rates of various grafting methods of Corylus avellana

The effect of different grafting periods on the xyloblast was compared and the results are shown in table 4.

TABLE 4 difference in wood bud grafting of rootstock with wood at different periods

The rhus avellana was grafted on the hybrid hazel of Pingguo by using the hazel of different parental stock ages, and the grafting survival rate is shown in Table 5.

TABLE 5 grafting survival rates of Corylus heterophylla of different rootstock ages

Age of rootstock/a	Grafted plant tree/plant	Number of surviving plants/plant	Survival rate/%	Growth of young shoots/cm
					1	157	139	88.54％	69
2	160	150	93.75％	97
					3	159	109	68.55％	101

Example 3

In 2015, different stocks and scions are grafted in spring in a manner of referring to example 1 in Beijing, so as to obtain grafting treatments of corylus heterophylla-David, corylus heterophylla-Liaohazelnut No. 8, corylus heterophylla-Liaohazel No. 8, corylus heterophylla-Jade pendant and the like, wherein the former part is the stock and the latter part is the scion. The experiment is carried out by taking hybrid hazelnuts without grafting as a control CK.

2015 + 2017, the overwintering freezing damage condition of annual branches of the hybrid hazel grafted trees in Beijing is investigated, and the investigation result is shown in Table 6.

TABLE 6 annual shoot desiccation investigation (Unit:%)

2015 + 2017, the statistics of the male inflorescence freeze injury rate of annual branches of the Pingguo hybrid hazel grafted tree in Beijing are investigated, and the investigation result is shown in Table 7.

TABLE 7 statistics of the male inflorescence freeze injury rate of different engrafted stocks (unit:%)

The results of the yield survey of the hybrid hazel grafted trees in Beijing in the single plant in 2015 + 2017 are shown in Table 8.

TABLE 8 average yield per plant (unit: kg) of each variety (line) after grafting

Year of year	CK	Huahazel-Dawei	Huahazel-Liaohazel No. 8	Huahazel-jade pendant	Remarks for note
						2015 years	0.20	0	0	0	Grafting
2016 (year)	0.15	0.05	0.15	0.10	Climate anomaly
						2017	0.16	0.18	0.24	0.26	Extremely low temperature in winter
2018 years old	0.18	0.43	0.36	0.50

Therefore, the hazel is used as the stock, and the grafted hybrid hazel can obviously improve the cold resistance and obtain better yield.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (10)

1. A grafting method for improving the cold resistance and drought resistance of hybrid hazel in Pingyou is characterized in that the method takes the hazel in Pingyou as a rootstock of the hybrid hazel in Pingyou for grafting.

2. The grafting method for improving the cold resistance and drought resistance of hybrid hazelnuts in Pink Europe according to claim 1, comprising the following steps:

a, collecting, shelling, sowing and seedling management of hazel seeds;

collecting and storing B Ping European hybrid hazel scions;

and C, selecting a hazel rootstock for grafting.

3. The grafting method for improving the cold resistance and drought resistance of hybrid hazel of Pink Europe according to claim 2, wherein the collection A is seed collection in the middle 8 th month of the year when the fruit is ripe.

4. The grafting method for improving the cold resistance and drought resistance of hybrid hazelnuts in accordance with claim 2, wherein in the step A, sowing is carried out, and the collected hazelnut seeds are sowed in autumn in the same year or sowed in sand until spring sowing is carried out in the next year.

5. The grafting method for improving the cold resistance and drought resistance of hybrid hazel of Pingyou according to claim 2, wherein the collection B is to select an annual branch which grows robustly at the periphery of the crown of the hybrid hazel nut tree, cut off the thin and weak part at the top and the thin and small part of the bud at the base, only leave the part containing 1-2 full buds in the middle of the branch as a scion, the thickness is 0.7-0.9cm, and the length is 5-7 cm.

6. The grafting method for improving the cold resistance and drought resistance of hybrid hazelnuts in Pink Europe according to claim 2, wherein the rootstock C is selected, the robust hazelnut seedlings growing for 1-2 years are selected as the rootstock, the root diameter of the rootstock is required to reach more than 0.8cm, and the rootstock is free of diseases, insect pests and mechanical damage.

7. The grafting method for improving the cold resistance and drought resistance of hybrid hazelnuts in Pink Europe according to claim 2, wherein the grafting time of grafting C is 3 months and 12 days to 4 months and 5 days.

8. The grafting method for improving the cold resistance and drought resistance of the hybrid hazel of Pingyou as claimed in claim 2, wherein the grafting step C is to graft 1-2 years old root stocks of the hazel seedlings by adopting a method with wood bud grafting, to trim the root systems of the selected root stocks, wherein the trimmed length of the root systems is about 7cm, then to cut the root stocks at the position of 15cm high, to cut off the bark by 2-3cm, and to flatten the bark; selecting bud slices on the scion according to the stock, cutting off the bud slices on the scion by using a grafting knife, flattening the bud slices, then pasting the bud slices on the cut surface of the stock, aligning the pasting surface, and tightly binding the bud slices by using plastic films with the width of 1.5cm and the length of 25-30cm to expose the bud part of the tree.

9. The grafting method for improving the cold resistance and drought resistance of hybrid hazelnuts in accordance with any one of claims 2 to 8, further comprising the steps of:

d, managing grafted seedlings;

e, outplanting and storing the nursery stock.

10. The use of the grafting method for improving the cold resistance and drought resistance of the hybrid hazel of Pink Europe according to any one of claims 1 to 9 in propagation of the hybrid hazel of Pink Europe.