WO1997039616A1

WO1997039616A1 - Grafting method

Info

Publication number: WO1997039616A1
Application number: PCT/IL1997/000133
Authority: WO
Inventors: Moshe Bar-Yoseph
Original assignee: State Of Israel - Ministry Of Agriculture
Priority date: 1996-04-25
Filing date: 1997-04-24
Publication date: 1997-10-30
Also published as: IL118034A; IL118034A0; AU2402297A

Abstract

The invention relates to a method for producing a composite tree comprising the steps of approach grafting at least two rootstocks (10, 12) with different horticultural qualities early in their development and allowing the approach grafter rootstocks to grow together to form a single rootstock. A polymer rootstock comprising two intermingled rootstocks (20) each with different qualities which are approach grafted early in their development and grown to form a single rootstock is also disclosed.

Description

GRAFTING METHOD FIELD OF THE INVENTION The present invention relates to methods for production of grafted trees generally, and particularly to methods for production of tree rootstocks.

BACKGROUND OF THE INVENTION

Grafting, a well known practice in horticultural production, is aimed at combining a rootstock adapted to a given edaphic condition together with a scion having desired properties, such as good fruit quality or other high performance. The grafted combination should provide a tree which outperforms the ungrafted rooted varieties. Generally the scion is grafted on the rootstock either in the nursery or in the grove.

One form of grafting rootstocks known in the art is inarching, which involves grafting rootstock and scion while both are still growing independently. Inarching is often used when the current root system is weak and must be replaced to save the tree. A number of seedlings are planted around the tree and they are approach-grafted onto the stem. The graft is usually held in place by nailing.

Inarching is discussed in horticultural literature, e.g., J. Janick, Horticultural Science, 1979, W. H. Freeman & Co, San Francisco CA, USA, "Dwarfed Fruit Trees", by Tukey, The MacMillan Co., New York, "Temperature-Zone Pomology", Westwood, 3rd Edition, and "Rootstocks for Fruit Trees, R.C. Rom & R.F. Carlson, John Wiley & Sons, 1987.

SUMMARY OF THE INVENTION

The present invention provides an improved method for the production of tree rootstock. Two or more rootstocks with different horticultural qualities are approach grafted early in their development and are grown as a dimer or polymer rootstock in a container. The dimer or polymer rootstocks are grafted with a bud or a budstick approached at one, two or all ofthe rootstocks forming the polymer. The new method is considered a major improvement on previously described budding grafting and inarching methods as it produces a new type of rootstock which combines the advantages of two or more rootstocks from the early stage of nursery plant production.

For example, seeds of different citrus and other fruit crops may be grown in a nursery bed and after reaching a height of 20 - 30 cm or more, may be defoliated at their base, wounded slightly and approach grafted and stuck together by wrapping with plastic, parafilm or any other clipping or wrapping device. Instead of seed, one may use rootstock or varietal cuttings or a combination of cutting from one or more rootstocks, varieties and seedlings of other rootstock. The resulting combinations of rootstocks are defined as dimeric (di/mer) or polymeric (po/mer) rootstocks and they differ from any previously described nursery grown rootstocks.

The di/mer or po/mer rootstocks are transferred to individual containers, raised for several months and budded to a site including one ofthe rootstocks or alternatively at the site where the di/mer or po/mer were approached. Afterwards, bud development, plant raising in the nursery and field planting, follow ordinary nursery practices.

There is thus provided in accordance with a preferred embodiment of the present invention, a method for production of tree rootstocks including the steps of approach grafting at least two rootstocks with different horticultural qualities early in their development and allowing the approach grafted rootstocks to grow and form a single rootstock.

There is also provided in accordance with a preferred embodiment of the present invention, a method for production of tree rootstocks including the steps of providing at least two graft compatible young tree plants each with different horticultural qualities, defoliating the base of the at least two young tree plants not more that one year after the at least two young tree plants were transferred to soil, wounding the base of the at least two young tree plants by removing the bark, and approach grafting the at least two young tree plants.

There is also provided in accordance with a preferred embodiment of the present invention, a method for production of trees including the steps of providing at least two graft compatible young tree plants each with different horticultural qualities, defoliating the base of the at least two young tree plants not more than one year after the at least two young tree plants were transferred to soil, wounding the base of the at least two young tree plants by removing the bark, approach grafting the at least two young tree plants, and grafting a scion onto the approach grafted at least two young tree plants.

The at least two young tree plants may be seedlings or cuttings, or alternatively may be derived from plant tissue culture.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

Fig. 1 is a simplified flow chart of a method for production of tree rootstocks, in accordance with a preferred embodiment ofthe present invention;

Fig. 2 is a simplified pictorial illustration of the preparation of young tree plants to be grafted for the production of a rootstock, in accordance with a preferred embodiment ofthe present invention;

Fig. 3 is a pictorial representation of a rootstock grafted in accordance with a preferred embodiment ofthe present invention;

Fig. 4 is a pictorial representation of grafting a bud on the grafted rootstock of Fig. 3 in accordance with a preferred embodiment ofthe present invention; and

Fig. 5 is a pictorial representation of a scion developed from the bud of Fig. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is now made to Fig. 1 which is a simplified flow chart of a method for production of tree rootstocks, in accordance with a preferred embodiment of the present invention. The method for production of tree rootstocks includes selecting graft compatible young tree plants with different horticultural qualities. At least two young tree plants with different horticultural characteristics are then prepared for grafting. The preparation includes defoliating the base of young plants not more that one year after the young plants were transferred to soil.

The defoliated bases are then wounded by removing the bark, and the wounded surfaces are approach grafted. In approach grafting the wounded surfaces are brought into contact with each other and held in place with a bandage until the parenchymatous tissue from each young tree plant grows together to form a single stem.

The young tree plants may be seedlings less than one year after germination, tissue culture propagated plants less than one year after being removed from tissue culture, or cuttings of a second rootstock or variety less than one year after being established in soil.

An example of the preparation of young tree plants to be grafted for the production of a rootstock in accordance with the method of the present invention, will now be illustrated with reference to Fig. 2.

Seeds (not shown in Fig. 2) of rootstock cultivars Troyer and Sour Orange are germinated in soil in containers in a greenhouse and grow to seedlings 10 and 12, respectively. When Troyer 10 and Sour Orange 12 seedlings have reached 20 - 30 cm in height, they are each defoliated at the base and wounded at a surface designated by reference numbers 14 and 16, respectively. Wounded surfaces 14 and 16 are brought into contact (not shown in Fig. 2) and wrapped with a bandage 18 of Parafilm, commercially available from American National Can, Greenwich CT 06836, and continued to be grown in the greenhouse. Fig. 3 illustrates a resultant approach grafted rootstock 20 which is the result of grafting seedlings 10 and 12 of Fig. 2. Within a year, the resultant rootstock 20 may be grafted to a scion of a variety which yields desirable fruit such as Valencia sweet orange. For example, Fig. 4 is a pictorial representation of grafting a bud 30 on rootstock 20, and Fig. 5 is a pictorial representation of a scion 40 developed from bud 30. The resultant grafted tree thus combines the characteristic of Tristeza tolerance found in Troyer, the tolerance to calcium in the soil found in Sour Orange and the fruit characteristics found either in Troyer or Sour Orange.

The scope of the invention is not to be construed as limited by the illustrative embodiment set forth herein, but is to be determined in accordance with the appended claims.

Claims

1. A method for production of tree rootstocks comprising the steps of: approach grafting at least two rootstocks with different horticultural qualities early in their development and allowing the approach grafted rootstocks to grow and form a single rootstock.

2. A method for production of tree rootstocks comprising the steps of: providing at least two graft compatible young tree plants each with different horticultural qualities; defoliating the base of said at least two young tree plants not more that one year after said at least two young tree plants were transferred to soil; wounding the base of said at least two young tree plants by removing the bark; and approach grafting said at least two young tree plants.

3. A method for production of trees comprising the steps of: providing at least two graft compatible young tree plants each with different horticultural qualities; defoliating the base of said at least two young tree plants not more than one year after said at least two young tree plants were transferred to soil; wounding the base of said at least two young tree plants by removing the bark; approach grafting said at least two young tree plants; and grafting a scion onto the approach grafted at least two young tree plants.

4. A method according to either of claims 2 and 3 wherein said at least two young tree plants are seedlings.

5. A method according to either of claims 2 and 3 wherein said at least two young tree plants are cuttings.

6. A method according to either of claims 2 and 3 wherein said at least two young tree plants are derived from plant tissue culture.

7. A polymer rootstock comprising: at least two rootstocks with different horticultural qualities approach grafted early in their development and which are grown to form a single rootstock.