|
Simultaneous grafting and rooting of roses | AG0188 |
Graeme Thomson, Knoxfield
September 1994 |  |
To view the Adobe Acrobat file, you will need the Adobe Acrobat reader. |  PDF 28 kb | |
Rose plants are routinely propagated by rooting and budding in the field. Rootstock cuttings are planted out between May and July and in late spring rooted material is budded. Plants produced in this manner are not ready for flower picking for at least one year. In a quicker technique, sometimes known as "stenting", roses are simultaneously grafted and rooted under mist in a glasshouse to produce a plant in four to six weeks. Such a plant may flower after only four months. This method can yield from 200 to 400 plants per square metre in a five-week period, and can be used throughout the year.
Procedure
(a) Rootstock
Select either softwood (at a stage where leaves are well developed) or semi-hardwood material of 6-8 mm diameter from actively growing plants. It is advisable to remove all buds from the stock to overcome the problem of excessive suckering. However, some growers suggest that grafts are more likely to succeed and cuttings are more likely to survive if leaves at nodes are retained intact.
The length of stock can be varied between 50 and 400 mm. A 50 mm length will give acceptable results but stocks that are 100 mm long are easier to work with. Use of stocks longer than 100 mm is usually unnecessary and wastes material.
Rockwool is an excellent rooting medium, however, sand/peat mixes (for example, 1:1, 3:1, by volume) and peat/perlite mixes (for example, 1:3, 1:2, by volume) have also been used with success. In some cases rooting may be improved by using bottom heat (20-25°C) and/or an indolebutyric acid (IBA) basal dip. IBA can be applied in liquid form (50% alcohol) at 500-1000 mg/L for 5 seconds at 10 mm depth.
(b) Scion
Glasshouse-grown softwood/semi-hardwood cuttings with one or two well-developed leaves are the most suitable. Many growers also favour material taken from stems that carry well-aged flower buds. Final success may depend on the combination of varieties used for stocks and scions.
(c) Grafting
The type of graft chosen should ensure that a large cambium layer interface occurs for strong union and effective vascular connection. Whip (or tongue) grafts have been found to be slightly superior to saddle and wedge grafts. The graft union can be held together by tying with non-adhesive PVC tape but if short stocks/scions are used, pinning or clamping with pegs may be more convenient. Tape or pegs can be removed from three to five days after plants are taken from the mist bed. Six weeks after grafting, over 85% of unions should be successfully healed.
(d) Maintenance
Grafted cuttings are propagated in the mist bed, hence there is a need for careful monitoring of mist rates, and judicious use of fungicidal sprays. Fusarium and Botrytis infections are likely to occur and are generally controlled by weekly sprays of a suitable fungicide. Check with DPI for registered products.
The advice provided in this publication is intended as a source of information only. Always read the label before using any of the products mentioned. The State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.
|
