v Introduction:
• Grafting of woody plants has been common for centuries, but herbaceous grafting has only become popular recently in agricultural system.
• In vegetable production in greenhouse, most of the damage from continuous cropping is caused by soil- borne diseases & nematodes. So, grafting of fruit bearing vegetables is popular in Japan.
• Therefore the need for grafting in vegetables arises mainly to develop resistance to several biotic and abiotic stresses and to improve yield and quality but not to reduce the juvenility.
v HISTORY AND CURRENT STATUS:
• The production of grafted vegetable plants was first began in Japan and Korea in the late 1920s with watermelon (CitrulluslanatusMatsum. et Nakai) grafted onto pumpkin (Cucurbitamoschata) rootstock (Lee 1994)
• Soon after, watermelons (Citrulluslanatus) were grafted onto bottle gourd (Lagenariasiceraria) rootstocks.
• Eggplant (Solanummelongena) was grafted onto scarlet eggplant (Solanumintegrifolium Poir.) in the 1950s.
• Later, grafting was introduced to North America from Europe in the late 20th century and it is now attracting growing interest, both from greenhouse growers and organic producers (Kubota et al. 2008)
• Grafting of vegetables was originated as a random experiment in Korea and Japan.
• In temperate regions of the world summer season vegetables are grown under green houses. With the ban of fumigant fungicides and nematicides; since 1970s in European countries, grafting of susceptible scions on resistant rootstocks is become an effective alternative against soil borne pathogens.
• Moreover, in organic cultivation of vegetables grafting eliminates the use of chemicals in disease control.
• Because of the above said reasons it is now attracting growing interest, both from greenhouse growers and organic producers.
• This process is now common in Asia, parts of Europe and the Middle East (Davis et al. 2008).
• Grafting tomato plants has increased in European countries like Spain, France and Italy.
• Grafted tomato plants are produced to a tune of over 45 million ton in Spain and over 20 million ton in France and Italy.
• In Japan, the percentage of area using grafted plants to the total production area is 93% for water melons and 71% for cucumbers.
Even though grafting originated in East Asia, it didn’t get attention among the growers of South Asia. It became popularized in cold countries where year round cultivation of vegetables is being carried out under green houses.
In India, especially in Gujarat,Mr. Jayeshbhai Patel (A farmer of Bharadia village) has starting grafting in vegetables in many crops. He has also supplied so many grafted plants in many villages like, Jappatal, Jalgaon, Chokra, Bhradia, Manikpur (Navsari) of Gujarat.
v WHAT IS GRAFTING?
v WHY GRAFTING?
Ø Vegetables grown under greenhouses are severely affected by the various soil borne diseases and root-knot nematodes.
Ø An estimated loss of 68% in vegetable yield caused by soil borne diseases under continuous cropping (Takahashi 1984).
Ø The main reason for vegetable grafting is thus to improve their adaptation to stresses.
v High yield:
Grafting increase yield through…
• Enhanced water uptake.
• Enhanced nutrient uptake.
• Manipulating harvest period.
• Grafted plants gave more yield than the non-grafted ones in the greenhouse as well as in the open-field (Khah et al, 2006).
• Grafts have been used to improve yield when plants are cultivated in problematic soils. (Kacjan-Marsic and Osvald, 2004)
• Yield and Water Use Efficiency were higher in grafted plants.( Oztekin et al, 2009)
v Improving quality traits:
• Grafting increases number of marketable fruits and decrease number of malformed fruits in tomato. (Pandey and Rai, 2003)
• Flavor, pH, sugar, color, carotenoid content, and texture can be affected by grafting and the type of rootstock used. (Davis et al, 2008).
• An increase in ascorbic acid content in tomato was found with grafting.(Zhu et al. 2006)
• Grafted fruit had a better colour and highest lycopene content in tomato. (Chung et al., 1997)
• Earlier methyl bromide fumigation was used to control greenhouse diseases
- banned in 2005 in European countries
- Some undesirable effects on fruit quality
All these burst open into the technology “Grafting of Vegetables”
v SPECIES USED FOR GRAFTING PURPOSE:
Inter-generic grafting is used in the production of many fruit bearing vegetables i.e.
1. Cucumber grafted on pumpkin
2. Watermelon on bottle gourd
3. Melon on whitegourd
Interspecific grafting is generally applied to eggplant, scarlet eggplant and S. torvum are popular rootstock for eggplant production.
v OBJECTIVE / BENEFITS OF GRAFTING:
The main objective of grafting is to avoid soil-borne diseases such as Fusarium wilt in Cucurbitaceae and bacterial wilt in Solanaceae.
Ø Benefits:
1. Imparting disease and pest resistance
2. Avoiding nematode infestation
3. Minimizing the auto toxic effect
4. Providing cold hardiness
5. Improving quality traits
6. Manipulating the harvesting period
7. Reduced fertilizer and agrochemical application
8. Increase yield
Furthermore, the new restrictions regarding the use of methyl bromide give an incentive to develop and implement new technologies allowing farmers to cope with these constraints. So, vegetable grafting represents a useful alternative.
v HOW TO PERFORM GRAFTING?
Ø Basic prerequisites:
• Root stocks
• Scions
• Compatibility
• Grafting Aids
• Screen house
• Healing chamber/Grafting chamber
• Acclimatization chamber
v FACILITIES REQUIRED FOR GRAFTING:
Ø Screen house:
• Used for growing seedlings prior to grafting
• Should be constructed with 60-mesh nylon net.
• Arrange double door
• The upper half of the structure should be covered with a separate UV resistant polyethylene to prevent UV light penetration.
v Healing chamber/ grafting chamber:
• Used for formation of better graft union
• In this chamber grafts should be kept for 5-7 days
v Advantages of healing chamber:
• Reduces water stress by reducing transpiration
• Maintains high humidity
• Maintains optimum temperature
• Reduces light intensity
v Acclimatization chamber:
• Used for hardening the grafted seedling prior to transplanting and to prevent leaf burning and wilting of the just healed seedlings.
• Grafted seedling takes 7 to 10 days for acclimatization as hardening treatment.
v SIMPLE PROCEDURE FOR GRAFTING:
Grafting is commonly done when scion and root stock seedlings are young i.e. before the outgrowth of the first true leaf between the cotyledons.
When grafting is performed, it is important to increase the chances for vascular bundles of the Scion root stocks to come in contact by maximizing the area of the cut surface that are spliced together and by pressing the spliced cut surface together. After grafting about 300 C temperature and 95 % RH should be maintained for fast healing and better survival of graft age. Gradually, the RH is then lowered and the light intensity is increased.
v GRAFTING METHODS FOR VEGETABLES:
1. Cleft Grafting
2. Tongue Approach/Approach Grafting
3. Whole Insertion/Top Insertion Grafting
4. One Cotyledon/Slant/Splice grafting
5. Tube Grafting
6. Pin Grafting
7. Micro- grafting
8. Automated grafting
v Cleft grafting:
• It is a simple and easy method
• It is suitable for rootstocks with wide hypocotyls
• Can be practiced in all vegetables
v Tongue Approach/Approach Graft:
• Most widely used by farmers and small nurseries
• This method requires more space and labor compared to other methods but high seedling survival rate can be attained even by beginners.
• Grafted seedlings have a uniform growth rate
• It is not suitable for rootstocks with hollow hypocotyls
v Hole Insertion/Top Insertion Grafting:
• This is most popular in cucurbits.
• When scion and rootstock have hollow hypocotyls, this method is preferred (Hang et al., 2005)
• One person can produce 1,500 or more grafts/day
• To achieve a high rate of success, relative humidity should be maintained at 95%.
• After healing temperature should maintain at 21-36◦C up to transplanting.
v Slant grafting:
• It has recently been adopted by commerc seedling nurseries (Sakata et al., 2007).
• It is applicable to most vegetables.
• It has been developed for robotic grafting.
• Grafted plants should be maintained in the dark at 25 ◦C and 100% humidity for three days for graft union.
.JPG "Ankit Gadhiya- Grafting")
v Tube Grafting:
• It is similar to slant grafting except that in this method root stock & scion joined are held with an elastic tube instead of clips.
• It is more popular in tomato and Brinjal.
v Pin Grafting:
• It is also same as the slant grafting.
• In this instead of grafting clips, to hold the grafted position, specially designed pins are used.
• The ceramic pin is nearly about 15mm long and 0.5mm in diagonal width of the hexagonal cross-section.
v Micro-grafting:
Micro- grafting refers to in-vitro grafting using very small or micro-explants from meristematic tissues. It is often carried out to eliminate the viruses from infected plants because virus particles do not exist in the apical meristem. It is expensive.
v Automated Grafting:
• The first semiautomatic cucumber grafting system was commercialized in 1993.
• A simple grafting machine can produce 350–600 grafts/hour with 2 operators, whereas manual grafting techniques produce about 1,000 grafts / person / day (GU, 2006).
• A fully automated grafting robot performing 750 grafts/hour with a 90-93% success rate
v TOOLS, CLIPS AND GRAFTING AIDS:
Scion and rootstock are fixed with different typologies of clips or with plastic tubes with a side split. A ceramic pin can also be used in some cases to six plants. In addition, particularly when automation is adopted, instant glue is adopted. Grafting clips, tubes, tapes and pins have been used. A special knife with a self-feeding connection of skimmed milk to inactivate some potent virus has been developed in the Netherlands and Korea.
v HEALING AND ACCLIMATIZATION:
Grafted plants are usually healed and acclimated in a plastic tunnel. The tunnel is covered with materials which provide shade and maintain inside humidity: silver –cheese cloth (outside) and transparent film (inside).
Ø For a high survival rate in grafting…
Before grafting:
1. Expose the scions and rootstocks to sunlight for 2 to 3 days before grafting.
2. Drying of the potted soil where the scion and rootstock grow by controlled watering to avoid spindly growth.
3. Scion and rootstock with similar diameters are important to increase the survival rate.
After Grafting:
• Keep 100% RH for 3 days and then gradually reduce the humidity.
• Keep the light intensity at 3-5 k lux
v FIELD MANAGEMENT OF GRAFTS:
è Raised beds and shelters:
Ø Raised beds are highly recommended to minimize flooding.
Ø Clear polyethylene covered on raised beds can be used to protect the field plants from direct impact of heavy rainfall.
è Transplanting depth:
Ø The graft union should be placed above soil line while transplanting.
Sucker and adventitious root removal
Ø Timely removal of suckers developed from the rootstock after transplanting.
è Staking and pruning:
Ø Grafted plants should be staked two to three weeks after transplanting
Ø This will prevent vines from sliding down and the scion stem contacting the soil
è Water management:
Ø Plants with eggplant rootstocks require higher soil moisture than non-grafted tomato plants
v ECONOMIC FEASIBILITY:
• More labor required.
• High cost of grafted seedlings.
In Japan, grafted seedlings are almost four times the cost of seeds (Sakata et al, 2007).
• Special care is required
• Additional charge of transplanting in case of cucurbits.
• It can be overcome by the heavy yields
v ROBOTIC GRAFTING:
First robot developed was the “cutting-off cotyledon grafting” (CCG) system developed by IAN BRAIN of Japan to graft cucurbit vegetables. It takes three seconds to make a grafted plant with 95% survival rate.
v CASE STUDIES IN GRAFTING:
è TOMATO:
• Grafting in tomato is started around 1960 and 1970 (Edelstein 2004).
• Tomato production during the hot-wet season in most of the Southeast Asian countries is constrained by biotic and abiotic factors including flooding, impact of heavy rains, high temperature and high incidence of soil borne diseases such as bacterial wilt and nematodes (Palada and Wu 2007).
è POMATO:
• Pomato plant is a result of grafting of tomato on potato plants.
• We can reap tomatoes on the top of the plant and potatoes under the soil.
è CUCURBITS:
• Research on cucurbit grafting began in Japan around 1920 with a study on watermelon. Pumpkin was initially used as a rootstock with watermelon to prevent Fusarium wilt
• In 1949 Imazu recommended pumpkin (Cucurbitamoschata) as root stock to musk melon (cucumismelo var. inodorus) cultivar haramadhu as it confers resistant to Fusarium wilt and improves plant vigor
• Based on the results of various trials, mainly on Cucurbita spp., the Fusarium-wilt-resistant bottle gourd variety Renshi was eventually released in the 1980s
• China produces more than half of the world's watermelons and cucumbers (Cucumissativus L.) and approximately 20% of these are grafted (Davis et al. 2008).
• Momordicacochinchinensis is a dioecious plant. The female plants are graftedon to the Male plants to increase its production. 98% of graft success isobserved at NBPGR regional station, Trissur, Kerala. ICAR News, 2011, V. 17(1)
v PROBLEMS AND CONSTRAINTS ASSOCIATED WITH GRAFTED PLANTS:
1) Incidence of unexpected diseases such as virus infection in root stock seeds
2) Occurrence of secondary diseases such as anthracnose in bottlegourd, internal fruit decay or premature fermentation in melon and tobacco mosaic virus and others in tomato
3) Poor fusion of vascular bundles in grafted unions
4) Quality deterioration of fruits occurs such as decrease in firmness and shelf-life
5) High cost of grafted seedlings
v CONCLUSION / FUTURE PROSPECTS:
• Grafting provides a site specific management tool for soil borne diseases. It fits well into the organic and integrated crop production system. It reduces the need for soil disinfectants and thereby environmental pollution.
• Grafting technology has a potential in promotion of cultivation in non-traditional and fragile agro-eco system.
• Grafting is a rapid alternative tool to the relatively slow breeding methodology aimed at increasing biotic and abiotic stress tolerance of fruit vegetables.
• Since grafting gives increased disease tolerance and vigor to crops, it will be useful in the low-input sustainable horticultureof the future.
informative, Mr. ankit
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