Tomato grafting
Encyclopedia
Tomato Grafting has been utilized worldwide in Asia and Europe for greenhouse
and high tunnel
production and is gaining popularity in the United States. Typically, stock or rootstock
are selected for their ability to resist infection by certain soilborne pathogens or their ability to increase vigor and fruit yield. The scion
of the grafted tomato represents the upper portion of the plant and is selected for its fruit quality characteristics. There are several methods for grafting tomatoes and they have certain advantages and disadvantages. Once the grafts are made, the plants are moved into a chamber or environment with high relative humidity
(>90%)and low light levels to reduce water stress in the scion while the graft union forms.
of woody plants has been common for centuries, but herbaceous grafting has only become popular recently in agricultural systems. The cultivation of grafted vegetable
plants began in Korea
and Japan
at the end of the 1920s when watermelon
plants were grafted onto squash rootstock[1]. Since this time, this technique has spread throughout Asia and Europe. Currently, 81% of Korean and 54% of Japanese vegetable cultivation uses grafting . The use of this cultural technique is mainly carried out for intensive cropping systems like greenhouse and tunnel production. This method is especially popular for vegetable production in the orient, and the number of vegetables in 1998 was estimated to be 540 million transplants in Korea and 750 million in Japan . This technique has moved to the Mediterranean region as well, where the use of grafting has been proposed as a major component of an integrated management strategy for managing soilborne disease and increasing crop productivity. Grafted tomato transplant production has increased in Spain
from less than one million plants in 1999-2000 to over 45 million plants in 2003-2004. Grafted tomato is also cultivated in France
and Italy
, and over 20 million tomato plants were grafted in Morocco
in 2004 as a way to reduce soilborne disease and increase crop production .
Grafting can take place on a number of crops. However, because of the added expense, it is typically associated with melons, cucurbits, and members of the Solanaceae
family such as eggplant and tomato. Tomato grafting became popular in the 1960s as a way to reduce certain diseases caused by soilborne plant pathogens such as Raletonia solanacearum [1]. Currently, however, grafting is used to offer not only protection from certain diseases, but also tolerance to abiotic stress like flooding, drought, and salinity [2].
fruit yield. The first grafts in the early 20th century were made in order to diminiuch as Fusarium oxysporum on watermelons [2]. However, research has shown that this technique can be effective against a variety of fungal, bacterial, viral
, and nematode
diseases. Furthermore, many researchers are looking to utilize specific rootstocks as an alternative to methyl bromide-a soil fumigant that has been widely used until recently[4]. Grafting has been highly effective at overcoming abiotic stressors such as soil salinity, temperature extremes, and excessive soil moisture[2]. Grafting has also been utilized in order to reduce the effects of flooding in areas where a wet season may occur . Grafting tomato with tolerant rootstock has been highly effective at producing a saline-tolerant plant and research indicates that several rootstocks prevented the translocation of sodium
and chloride
into the shoot. Many of the most economically important vegetable crops like tomato, squash, cucumber, and watermelon are highly sensitive to thermal stress in the roots throughout vegetative development and reproduction. Whether using rootstock tolerant of hot or cold temperatures, the use of heat- or cold-tolerant resistant rootstock could lead to the extension of the growing season in either direction, resulting in better yield and economic stability through the year [2]. Although the vegetable grafting is typically associated with reduction of disease and/or abiotic stress, yield is often increased without the presence of these identified stressors. In tomato, increases in fruit yield are typically a result of increased fruit size . Research has shown that possible mechanisms for increased yield are likely due to increased water and nutrient uptake among vigorous rootstock genotypes. Stomatal conductance was improved in tomato when grafted onto vigorous rootstock[7]. Nutrient uptake for macronutrients such as phosphorus
and nitrogen
were enhanced by grafting .
tube or clip. This technique has been highly effective as it can be carried out when plants are very small, thereby eliminating the need for large healing chambers while increasing the output. Tube grafting has been adopted as the primary method for vegetable grafting on the farm as it can be easily carried out with small healing chambers with typical success rates ranging from 85 to 90 percent [14].
http://oardc.osu.edu/graftingtomato/graft.htm
http://www.uvm.edu/vtvegandberry/factsheets/graftingGHtomato.html
http://www.avrdc.org/LC/tomato/grafting.pdf
http://www.ars.usda.gov/is/AR/archive/jul05/fruit0705.htm
http://www.ces.ncsu.edu/depts/hort/greenhouse_veg/topics/topics-pages/Grafting.html
Vegetable Grafting Information Website: http://cals.arizona.edu/grafting
Greenhouse
A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings...
and high tunnel
High tunnel
High tunnels are unheated, plastic-covered structures that provide an intermediate level of environmental protection and control compared to open field conditions or heated greenhouses....
production and is gaining popularity in the United States. Typically, stock or rootstock
Rootstock
A rootstock is a plant, and sometimes just the stump, which already has an established, healthy root system, used for grafting a cutting or budding from another plant. The tree part being grafted onto the rootstock is usually called the scion...
are selected for their ability to resist infection by certain soilborne pathogens or their ability to increase vigor and fruit yield. The scion
Grafting
Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation...
of the grafted tomato represents the upper portion of the plant and is selected for its fruit quality characteristics. There are several methods for grafting tomatoes and they have certain advantages and disadvantages. Once the grafts are made, the plants are moved into a chamber or environment with high relative humidity
Relative humidity
Relative humidity is a term used to describe the amount of water vapor in a mixture of air and water vapor. It is defined as the partial pressure of water vapor in the air-water mixture, given as a percentage of the saturated vapor pressure under those conditions...
(>90%)and low light levels to reduce water stress in the scion while the graft union forms.
History of Vegetable Grafting
GraftingGrafting
Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation...
of woody plants has been common for centuries, but herbaceous grafting has only become popular recently in agricultural systems. The cultivation of grafted vegetable
Vegetable
The noun vegetable usually means an edible plant or part of a plant other than a sweet fruit or seed. This typically means the leaf, stem, or root of a plant....
plants began in Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
at the end of the 1920s when watermelon
Watermelon
Watermelon is a vine-like flowering plant originally from southern Africa. Its fruit, which is also called watermelon, is a special kind referred to by botanists as a pepo, a berry which has a thick rind and fleshy center...
plants were grafted onto squash rootstock[1]. Since this time, this technique has spread throughout Asia and Europe. Currently, 81% of Korean and 54% of Japanese vegetable cultivation uses grafting . The use of this cultural technique is mainly carried out for intensive cropping systems like greenhouse and tunnel production. This method is especially popular for vegetable production in the orient, and the number of vegetables in 1998 was estimated to be 540 million transplants in Korea and 750 million in Japan . This technique has moved to the Mediterranean region as well, where the use of grafting has been proposed as a major component of an integrated management strategy for managing soilborne disease and increasing crop productivity. Grafted tomato transplant production has increased in Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
from less than one million plants in 1999-2000 to over 45 million plants in 2003-2004. Grafted tomato is also cultivated in France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
and Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
, and over 20 million tomato plants were grafted in Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
in 2004 as a way to reduce soilborne disease and increase crop production .
Grafting can take place on a number of crops. However, because of the added expense, it is typically associated with melons, cucurbits, and members of the Solanaceae
Solanaceae
Solanaceae are a family of flowering plants that include a number of important agricultural crops as well as many toxic plants. The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear...
family such as eggplant and tomato. Tomato grafting became popular in the 1960s as a way to reduce certain diseases caused by soilborne plant pathogens such as Raletonia solanacearum [1]. Currently, however, grafting is used to offer not only protection from certain diseases, but also tolerance to abiotic stress like flooding, drought, and salinity [2].
fruit yield. The first grafts in the early 20th century were made in order to diminiuch as Fusarium oxysporum on watermelons [2]. However, research has shown that this technique can be effective against a variety of fungal, bacterial, viral
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
, and nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...
diseases. Furthermore, many researchers are looking to utilize specific rootstocks as an alternative to methyl bromide-a soil fumigant that has been widely used until recently[4]. Grafting has been highly effective at overcoming abiotic stressors such as soil salinity, temperature extremes, and excessive soil moisture[2]. Grafting has also been utilized in order to reduce the effects of flooding in areas where a wet season may occur . Grafting tomato with tolerant rootstock has been highly effective at producing a saline-tolerant plant and research indicates that several rootstocks prevented the translocation of sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
and chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
into the shoot. Many of the most economically important vegetable crops like tomato, squash, cucumber, and watermelon are highly sensitive to thermal stress in the roots throughout vegetative development and reproduction. Whether using rootstock tolerant of hot or cold temperatures, the use of heat- or cold-tolerant resistant rootstock could lead to the extension of the growing season in either direction, resulting in better yield and economic stability through the year [2]. Although the vegetable grafting is typically associated with reduction of disease and/or abiotic stress, yield is often increased without the presence of these identified stressors. In tomato, increases in fruit yield are typically a result of increased fruit size . Research has shown that possible mechanisms for increased yield are likely due to increased water and nutrient uptake among vigorous rootstock genotypes. Stomatal conductance was improved in tomato when grafted onto vigorous rootstock[7]. Nutrient uptake for macronutrients such as phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
and nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
were enhanced by grafting .
Tomato Grafting Methods
There are a variety of methods for grafting vegetable crops. Cleft grafting occurs when a V-shape is cut into the rootstock and a complementing wedge-shaped scion is inserted. The graft is then held with a small clip until healing occurs . Approach grafting involves notching opposing sides of the stems of the rootstock and scion, and then using a clip to hold the stems together while they fuse. Once the graft has healed, the original scion is then cut off of the desired rootstock and the unused rootstock is detached from the scion . Micrografting is a new technique that has been recently integrated into micropropagation production for hybrid tomato. This method uses micropropagated scion shoots that grafted onto 3 week-old rootstock seedlings . The most common commercial technique for grafting tomato is tube grafting. Tube grafting takes place when the scion and rootstock are severed as seedlings and reattached with a small, siliconeSilicone
Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications , cookware, and insulation....
tube or clip. This technique has been highly effective as it can be carried out when plants are very small, thereby eliminating the need for large healing chambers while increasing the output. Tube grafting has been adopted as the primary method for vegetable grafting on the farm as it can be easily carried out with small healing chambers with typical success rates ranging from 85 to 90 percent [14].
- Approach Grafting is done by cutting opposing and complementary notches in the stem of the rootstock and scion. The complementary notches are fit together and held with a spring clip or some type of tape. Once the graft union has healed, the root system is cut from the scion plant and the shoot is removed from the rootstock plant[12].
- Cleft Grafting is carried out when the plants are slightly larger, and a V-shaped cut is made in the stem of the scion. The scion is then inserted into the rootstock, which has a vertical slice cut down the center of the stem. The rootstock and scion are then held together by a spring clip while the graft union forms[11].
- Tube Grafting or Japanese Top-Grafting is carried out when the plants are very small and the rootstock and scion are held together with a 1.5–2 mm silicone clip or tube[15].
Links/Resources
http://www4.ncsu.edu/~clrivard/TubeGraftingTechnique.pdfhttp://oardc.osu.edu/graftingtomato/graft.htm
http://www.uvm.edu/vtvegandberry/factsheets/graftingGHtomato.html
http://www.avrdc.org/LC/tomato/grafting.pdf
http://www.ars.usda.gov/is/AR/archive/jul05/fruit0705.htm
http://www.ces.ncsu.edu/depts/hort/greenhouse_veg/topics/topics-pages/Grafting.html
Vegetable Grafting Information Website: http://cals.arizona.edu/grafting