TECHNICAL ASPECTS OF GRAFTING LECTURE GIVEN BY: Ing. Cathrin Steenhoek DISCLAIMER • The end results present in the presentation are mostly • based on Dutch conditions and on experience from tests and practice. Although the presentation has been compiled with the utmost care, the Ruiter Seeds accept no responsibility whatsoever for the results of the grafting method shown. Introduction in Grafting Grafting is an easy way to produce new seedlings, which can tolerate various stresses. The grafting of cultural varieties onto a rootstock is a well known process and has been practiced for many years. Actually the grafting itself has a long history. Introduction in Grafting History of grafting: • known in China 1000 years A.C. • Aristoteles speaks about this topic in details (383 - 322 A.C.) • grafting was popular during the Roman Empire • during Renaissance the interest in Grafting Technique increased • grafting was used by the UK in XVI century Introduction in Grafting • Japan starts grafting in 1914 in order to prevent Fusarium • • • in watermelon Nara Agricultural University published in 1917 the grafting technique “Pua” (cleft grafting) Watanabe developed in 1923 the “Pua Oblicua” (other method of cleft grafting) Approach Technique in Japan was introduced in 1950 from Europe Introduction in Grafting • Holland started grafting of Cucurbits in 1947 • in 1962 grafting of Solanacea started in Europe • top grafting is a rapidly growing technique for growers; the number of grafted plants is increasing year by year • most common method now: Japanese Top Grafting Introduction in Grafting Japanese Top Grafting • cut off the rootstock at a 45º angle • cut off the variety at a 45º angle • put the scion (variety) straight on top of the rootstock • keep it together with a silicon grafting clip Grafting process Stages of grafting 1. Planning 2. Seeding the rootstock 3. Seeding the variety 4. Preparation 5. Grafting handling 6. Fusion 7. Pinching 8. Potting and spacing Grafting process - Planning • • • • make choice of the rootstock depending on: – resistances (Beaufort, Maxifort TmKNVF2Fr) – vigour desired make choice of the cultural variety make choice of the clip size (Ø1,2 / 1,5 / 2,0 / 2,5 mm) germination trials of the rootstock and the variety --> when is the stem of the plant thick enough for the clip ? --> what is the germination behavior ---> what is de germination percentage? Grafting process - Planning • sowing date depends on Root stock Same size of stem • Variety • plant growth (in the specific climate conditions) stems of the rootstock and scion must have the same thickness rootstock and scion can only be grafted together during a short period Grafting process - Seeding rootstock • Beaufort and Maxifort are light germinator’s; the amount • • • • • • • of light being the most important factor to achieve even growth of the plants germination temperature 24ºC / 26ºC cover lightly to prevent dehydration, for example with vermiculite (nr. 3) keep tray surface wet enough EC 1.5 - 2.0 mS/cm pH 6.0 - 6.5 4.500 lux/m2 (05:00 – 16:00hrs) sowing date depends on the results of the germination trial Grafting process - Seeding rootstock Grafting process - Seeding variety • sowing date depends on • • the results of the germination trial sowing date mostly 1 to 3 day’s later than the rootstock follow your own way of doing… Grafting process - Preparation Grafting process - Preparation The tunnel • in area without direct sunlight • use strong transparent plastic (0,05 mm) • 40 a 50 cm high • only use new (clean) plastic • only use clean other material • don’t make the tent or tunnel too big / long • next grafting day - next tunnel... Grafting process - Preparation Grafting process - Preparation Grafting process - Preparation The plants • the rootstock must be sorted according to stem thickness, at least 2 day’s before grafting (plants need time to recover) • take hold of the plants by the plug • the ideal thickness for start grafting is 1.5mm • sorting gives the plants more space for the grafting handling (distance between stems about 8 cm) and gives better growth of the rootstock • spacing the variety is not necessary (but can be useful) Grafting process - Preparation Grafting process - Preparation Grafting process - Preparation Working place • avoid direct sunlight during the grafting handling and on the grafted plants • grafting place if possible next to the tunnel • no transport, if possible • grafted tray’s must be placed into the tunnel very quickly • clean working place, new clips and new knives • desinfect your hands (solution of Dettol or Vircon) • don’t smoke during grafting or next to the plants Grafting process - Preparation Grafting process - Preparation Grafting process - Preparation Grafting process - Grafting handling Method 1 • first cut all the heads of the rootstock in a single tray at an angle of ± 45 degrees • by cutting them on a angel, you get a larger cutting surface, so that the scion can attach itself better to the rootstock Grafting process - Grafting handling • it is not necessary to retain the lobes when cutting • • • • (but possible) grafting point rootstock approx. 2,5 cm high (2 fingers) if plants are planted out into soil the grafting point might be higher if the grafting point is too low, there is a chance that the cultural variety will form roots if the grafting point is too high, the head will become too heavy and you have to use sticks to avoid damage Grafting process - Grafting handling • attach the grafting clip • clips are made of soft • silicon with an opening on one side to put the clip on the plant without damaging the stem prepare all rootstocks of the tray Grafting process - Grafting handling Grafting process - Grafting handling • clips are also available with a cane eye to prevent the grafted plants from falling over • use these clips to prick clean canes carefully alongside the plants • this can be useful for instance for eggplants or quite big tomato plants Grafting process - Grafting handling • cut off the variety at the • • same angle (45º) as the rootstock cut only the quantity needed for the prepared tray with the rootstocks in the summer spray lightly with clean tap water to prevent dehydration of the variety just cut Grafting process - Grafting handling • the cutting point of the cultural variety • depends on plant growth the head must have at least 2 fully grown heart-shaped leaves too many leaves --> head becomes too heavy and may fall over too small leaves --> head is too sensitive • • • • stem of the scion of ±1.5 cm is long enough always check the necessary stem thickness if necessary, modify the cutting point retaining the cotyledons is not strictly necessary • • Grafting process - Grafting handling • ease the scion into the • • • grafting clip, one at a time move the clip or stem a little, if necessary rootstock and cultural variety has to connect very well the cutting surface must make full contact Difference in size of cutting surface between the scion and the rootstock : the plants will not grow well onto each other or not at all !! Grafting process - Preparation Grafting process - Grafting handling Method 2 • grafting plant by plant • using new / other tray for grafted plants • common method in hot areas • all comments regarding care, plant quality, size of the plant and stems are the same as for method 1 • advantage: stem of rootstock or variety can’t dry off spacing of the rootstock is optional • disadvantage: takes more time for the first grafted plants overall grafting speed is slower Grafting process - Grafting handling Grafting process - Grafting handling • place the grafted plants / tray’s in the tunnel immediately! • moisten the plants or / and the plastic in the tunnel using a fine mist of clean tap water Grafting process - Grafting handling Grafting process - Grafting handling • (re)close the tent / tunnel carefully after each tray this is the only way to maintain the right climate for the plants • temperature inside tent / tunnel max. 28ºC; a higher temperature can seriously reduce the success ratio !! (depending on the hardness of the plants and the humidity in the greenhouse) • best grafting temperature around 22 / 23 ºC (but as close as possible to the greenhouse temperature) Grafting process - Grafting handling Grafting - Potting and spacing • it is not necessary to • remove the clip clips will drop off of their own You can now cultivate the plants further in your usual fashion. With rootstocks from De Ruiter Seeds you are ensured of a strong basis for your plants. We wish you every success!
