Method of propagation of woody plants with large seeds

Abstract

FIELD: agriculture.SUBSTANCE: invention which can be used in fruit growing and ornamental gardening. The method involves micro-grafting into the epicotyl in a scissure. Stratified seeds are germinated until the juvenile stage of rootstock development. When the epicotyl reaches a length of 4-6 cm and a diameter of 2-4 mm at a height of 2-3 cm, the epicotyl is cut and split and micrografting is performed. The graft and the grafting site are wrapped with Parafilm tape, on top of which a piece of aluminum foil tape is secured.EFFECT: invention ensures an increase in the percentage of successful long-lasting grafts of woody plants with large seeds.1 cl, 2 dwg, 2 ex

Description

[0001] The invention relates to agriculture and can be used in fruit growing and ornamental gardening for propagating plants with large seeds (chestnuts and other nut-bearing trees, oaks, and pome fruits). A method for propagating woody plants is described in patent US10463013B2, "Methods for micrografting avocados and other woody plants."

[0002] The method consists of several key stages:

[0003] The seeds are peeled and sterilized. The sterile seeds are germinated in the dark on a basic nutrient medium ( 1 / 2MS) without hormones. Seedlings are ready for grafting at 14-21 days of age, when the hypocotyl reaches a length of 4-6 cm. Scions are washed, sterilized in 10% sodium hypochlorite for 10 minutes, then rinsed in sterile water to remove the sterilizing agent. Branches are thoroughly washed and processed. Then, buds or shoots are superficially sterilized with 10% bleach for 10 minutes. Microscion is obtained under sterile conditions by cutting off vegetative buds (axillary or apical) about 1 cm long with a sharp scalpel.

[0004] The cotyledons and apical bud are completely removed from the etiolated rootstock. Then, using a sharp blade, a vertical split (V-shaped incision) 1.0-1.5 cm deep is made in the upper part of the hypocotyl. The base of the isolated scion bud is cut off at both ends to form a wedge, so that it perfectly matches the split in the rootstock.

[0005] Connection: The microscion is inserted into the cleft in the rootstock. Key requirement: The cambium layers of the scion and rootstock must be as closely aligned as possible. This ensures fusion.

[0006] To secure the rootstock-scion connection, sterile tape (Parafilm M®) is used, which is wrapped around the grafting site.

[0007] Fusing occurs at a temperature of 25±2°C and a 16-hour photoperiod. After 4-6 weeks, complete fusion occurs, and the plant begins to grow. After fusion, the plants are carefully removed from the test tubes, the roots are washed to remove the agar, and they are planted in a sterile substrate under high humidity, which is gradually reduced.

[0008] The main drawback of the known solution is the labor-intensive in vitro process, the use of sterile conditions, and artificial nutrient media. Plant adaptation also requires additional conditions with high humidity and the use of a sterile substrate, which entails additional material costs.

[0009] The closest to the invention in terms of the set of essential features is the method of micro-grafting chestnut into the epicotyl; this method is described in ''The Structure of Graft Unions in European Chestnut Using Different Grafting Methods'' August 2005, HortScience 40(5)

[0010] DPI: 10.21273 / HORTSCI.40.5.1474 Authors: Umit Serdar, Ondokuz Mavis University, Bulent Kose, Fatma Yilmaz Country: Türkiye

[0011] In the known method of epicotyl grafting, germinated seeds were planted in pots (30 × 40 cm) filled with a substrate containing 3 / 4 soil and 1 / 4 crushed pine needles. Young seedlings with 6-9 leaves, with stems 20.7 ± 1.5 cm long, were used. The epicotyl was cut to 4-7 cm and split. Then the lower part of the scion was cut into a wedge shape and inserted into the epicotyl, as in the conventional cleft grafting method (Sawano et al., 1983). After transplantation, the graft site was tied with Parafilm plastic tape, which was left in place for two months.

[0012] The main drawback of the known solution:

[0013] 1. Rootstocks used have already developed 6-9 leaves, meaning the epicotyl zone has begun to lignify, and the tissues in this zone have lost their juvenile properties, which affects the speed and quality of fusion with the rootstock. In addition to lower juvenility, such rootstocks have a less flexible structure and may adhere poorly to the scion.

[0014] The storage substances of seeds, hormones spent on the growth of rootstocks up to the stage of 6-9 leaves, are spent on the development of the rootstock shoot, most of which is cut off before grafting.

[0015] This study uses Parafilm tape, which has high light transmittance, allowing light to easily reach the scion-rootstock fusion zone and destroy endogenous auxins. Auxins play a crucial role during rootstock-scion fusion, promoting the expansion of new tissue cells formed at the rootstock-scion interface. However, auxins are easily destroyed by light, leading to a higher rate of incomplete graft union and subsequent rootstock rejection.

[0016] Furthermore, growing rootstocks to the age of 6-9 leaves is unreasonably long, which entails additional costs for their cultivation, and pots of 30-40 cm in size used at the first stage of development take up a significant area, which also positively correlates with the costs of artificial lighting if the work was carried out in early spring.

[0017] Analysis of known technical solutions revealed the need to create a method for propagating woody crops that would ensure a high percentage of successful grafting of woody plants such as chestnut, oak and other nut-bearing trees and a short period of time for growing the rootstock.

[0018] Technical result of the proposed invention: Increasing the percentage of successful long-lasting grafts of woody plants with large seeds.

[0019] To solve the above problem and achieve the stated result in the method of propagating woody plants with large seeds, which involves micro-grafting into the epicotyl in a split, in accordance with the proposed solution, stratified seeds are germinated to the juvenile stage of rootstock development, when the epicotyl length reaches 4-6 cm and the diameter is 2-4 mm, at a height of 2-3 cm, the epicotyl is cut and split and micro-grafting is performed, the scion is wrapped with Parafilm tape, on top of which a piece of aluminum foil tape is fixed.

[0020] The key features characterizing the invention include the use of rootstocks at a more juvenile stage of development, the use of Parafilm tape to completely wrap the graft site and scion, and the attachment of a piece of aluminum foil tape over the rootstock-scion junction. The use of smaller pots—9x9x14.

[0021] Use an epicotyl rootstock that has reached 4-6 cm in size, before the seedling develops leaves. Selecting an earlier rootstock will reduce rootstock preparation time and maintenance costs. Due to its more juvenile stage of development, the more flexible tissues adhere more closely to the scion tissues, promoting better fusion of the rootstock and scion pair.

[0022] After joining the scion and rootstock pair, the graft is wrapped with Parafilm tape. The scion is also completely wrapped, preventing water loss. A 2-2.5 cm wide piece of aluminum foil tape is secured over the graft site.

[0023] The proposed method is illustrated in photographs.

[0024] Figure 1 shows a grafted chestnut with a piece of aluminum foil tape removed after the rootstock-scion pair has been fused.

[0025] Fig. 2 shows the fusion site of the rootstock-scion pair of the chestnut (Castanea crenata) with the Ozark chestnut (Castanea ozarkensis).

[0026] Examples of the method. Example 1.

[0027] Micrografting was carried out using sprouted seeds of the serrated chestnut (Castanea crenata) and a scion - a cutting of the Ozark chestnut (Castanea ozarkensis)

[0028] The reproduction method includes the following steps:

[0029] 1. Germination of stratified seeds until the epicotyl length reaches 4-6 cm and the diameter at a height of 2 cm is 2-4 mm.

[0030] 2. Cuttings of pre-prepared rootstocks with a diameter of 2-4 mm with 1-2 buds, wiped with 70% ethyl alcohol.

[0031] 3. The sprouted seeds are removed from the substrate in which they were germinated, the epicotyls are washed to remove any remaining substrate under running water, placed in a large plastic container and covered with a lid.

[0032] 4. Remove the prepared sprouted seeds from the box. A cut is made at a height of 2-3 cm, and the epicotyl is split into two halves. A sharp, wedge-shaped scion is grafted onto the seedlings using the same method as the cleft grafting. Cuts are made on both the rootstock and scion with a blade.

[0033] 5. After joining the rootstock and scion pair, wrap them with Parafilm tape 5 cm long and 4-6 mm wide. The scion is completely wrapped in Parafilm tape, and the grafted material is placed in a second plastic container labeled with the variety name.

[0034] 6. Once the grafting process is complete, the grafted chestnut seedlings are transplanted into 9x9x14 plastic pots with a substrate consisting of 70% high-moor peat and 30% perlite. After planting, a 3 cm long, 2-2.5 cm wide piece of aluminum foil tape is secured to the grafted area over the Parafilm tape. The pots are placed in boxes and kept at a temperature of 21-25°C (70-77°F). Ten to 14 days after the buds have awakened and the growth cone has appeared, the grafted seedlings are transferred to a 16-hour light cycle.

[0035] Example 2

[0036] The sprouted seeds of the soft chestnut (Castanea mollissima) were used as a rootstock, and the scion - the soft chestnut variety ''Gideon''. Micrografting in the epicotyl includes first-year sprouts as a rootstock, the rootstock-scion connection using the cleft grafting method is distinguished by a more juvenile stage of rootstock development (at the stage of growth cone formation instead of the 6-9 leaf stage), complete wrapping of the scion with Parafilm tape, fixing a piece of aluminum foil tape in the grafting area over the Parafilm tape, smaller pots are used - 9 × 9 × 14, instead of 30 × 40, which saves space by more than 9 times. In this case, a peat / perlite substrate is used instead of soil with pine needles, which is a more affordable and technologically advanced solution.

[0037] The technical and economic advantage of the proposed method is its high efficiency and minimal time spent preparing rootstocks. This reduces the time and cost of rootstock maintenance, reduces the cost of purchasing scions per unit of successfully grafted plant material, and saves space and energy.

Claims

A method for propagating woody plants with large seeds, which involves micro-grafting into an epicotyl in a split, characterized in that the stratified seeds are germinated until the juvenile stage of the rootstock development, when the epicotyl reaches a length of 4-6 cm and a diameter of 2-4 mm, at a height of 2-3 cm, the epicotyl is cut and split and micro-grafting is carried out, the scion and the grafting site are wrapped with Parafilm tape, on top of which a piece of aluminum foil tape is fixed.

Images