Archive for the ‘Grafting’ Category

New grafting technique could combat the disease threatening Cavendish bananas

by University of Cambridge

New grafting technique could combat the disease threatening Cavendish bananas
Date palm 2.5 years after grafting. Inset shows a magnified region at the base of the plant, with the arrowhead pointing to the graft junction. Credit: Julian Hibberd

Scientists have found a novel way to combine two species of grass-like plant including banana, rice and wheat, using embryonic tissue from their seeds. The technique allows beneficial characteristics, such as disease resistance or stress tolerance, to be added to the plants.

Grafting is the technique of joining the shoot of one plant with the root of another, so they continue to grow together as one. Until now it was thought impossible to graft grass-like plants in the group known as monocotyledons because they lack a specific tissue type, called the vascular cambium, in their stem.

Researchers at the University of Cambridge have discovered that root and shoot tissues taken from the seeds of monocotyledonous grasses—representing their earliest embryonic stages—fuse efficiently. Their results are published today in the journal Nature.

An estimated 60,000 plants are monocotyledons; many are crops that are cultivated at enormous scale, for example rice, wheat and barley.

The finding has implications for the control of serious soil-borne pathogens including Panama Disease, or ‘Tropical Race 4’, which has been destroying banana plantations for over 30 years. A recent acceleration in the spread of this disease has prompted fears of global banana shortages.

“We’ve achieved something that everyone said was impossible. Grafting embryonic tissue holds real potential across a range of grass-like species. We found that even distantly related species, separated by deep evolutionary time, are graft compatible,” said Professor Julian Hibberd in the University of Cambridge’s Department of Plant Sciences, senior author of the report.

The technique allows monocotyledons of the same species, and of two different species, to be grafted effectively. Grafting genetically different root and shoot tissues can result in a plant with new traits—ranging from dwarf shoots, to pest and disease resistance.

“I read back over decades of research papers on grafting and everybody said that it couldn’t be done in monocots. I was stubborn enough to keep going—for years—until I proved them wrong,” said Dr. Greg Reeves, a Gates Cambridge Scholar in the University of Cambridge Department of Plant Sciences, and first author of the paper.

He added: “It’s an urgent challenge to make important food crops resistant to the diseases that are destroying them. Our technique allows us to add disease resistance, or other beneficial properties like salt-tolerance, to grass-like plants without resorting to genetic modification or lengthy breeding programs.”

The world’s banana industry is based on a single variety, called the Cavendish banana—a clone that can withstand long-distance transportation. With no genetic diversity between plants, the crop has little disease-resilience. And Cavendish bananas are sterile, so disease resistance can’t be bred into future generations of the plant. Research groups around the world are trying to find a way to stop Panama Disease before it becomes even more widespread.

Grafting has been used widely since antiquity in another plant group called the dicotyledons. Dicotyledonous orchard crops including apples and cherries, and high value annual crops including tomatoes and cucumbers, are routinely produced on grafted plants because the process confers beneficial properties—such as disease resistance or earlier flowering.

The researchers have filed a patent for their grafting technique through Cambridge Enterprise. They have also received funding from Ceres Agri-Tech, a knowledge exchange partnership between five leading UK universities and three renowned agricultural research institutes.

“Panama disease is a huge problem threatening bananas across the world. It’s fantastic that the University of Cambridge has the opportunity to play a role in saving such an important food crop,” said Dr. Louise Sutherland, Director Ceres Agri-Tech.

Ceres Agri-Tech, led by the University of Cambridge, was created and managed by Cambridge Enterprise. It has provided translational funding as well as commercialisation expertise and support to the project, to scale up the technique and improve its efficiency.

Explore furtherCoconut tree cloning breakthrough will help propagation and preservation

More information: Julian Hibberd, Monocotyledonous plants graft at the embryonic root–shoot interface, Nature (2021). DOI: 10.1038/s41586-021-04247-ywww.nature.com/articles/s41586-021-04247-yJournal information:NatureProvided by University of Cambridge

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Grafting helps pepper plants deal with drought

  • Grafting helps pepper plants deal with drought

Copyright: Wikipedia

Speed read

  • Peppers grown in many developing countries
  • Grafter plants yield 40 per cent more, tests show
  • Helps increase resilience against drought
Joining a high-yield pepper plant sapling to the roots of a strong and resistant variety could help pepper farmers cope with lower rainfall, a study has found.

An experiment using the technique of merging two plants, known as grafting, resulted in higher fruit yield during periods of less rain. Plants also grew much better in salty soil, a by-product of drought, the researchers found. The results of the study were published last month in Scientia Horticulturae.

Peppers are native to Mexico, but are grown in many developing countries – both as the bell pepper vegetable and chili pepper to make spices. The plant is a particularly important commercial crop in Latin America and Asia. Around 26 million tons of peppers were grown commercially around the world in 2007.

“Grafting allows for the combination of the desired shoot characteristics with roots that can overcome environmental stress”

Angeles Calatayud

The Spanish research team took saplings of commercially grown Adige Lamuyo peppers and grafted these onto wild peppers. They also grew the pepper on its own as a control group. For the third part of the experiment, the researchers grew the grafted and original plants outdoors in one normal field and one with salt and irrigation problems.

The research showed that peppers grafted onto Capsicum anuum, a wild pepper plant, were much better at dealing with drought conditions and high levels of salt in the soil. The yield of the grafted plants was 40 per cent higher than that of the ungrafted plants grown from seed.

“Pepper grafting could become an environmentally friendly adaptation strategy,” says Angeles Calatayud, a researcher at the Instituto Valenciano de Investigaciones Agrarias in Valencia, Spain, and co-author of the paper. “Grafting allows for the combination of the desired shoot characteristics with roots that can overcome environmental stress.”

Grafting is done by cutting a plant off near the root, shaping its stalk into a wedge and fitting this into a matching groove on the severed stem of another plant. The technique is used for many other vegetables as a means of dealing with stress factors such as extreme climate conditions and toxic soil. Grafting is common in the farming of watermelon, tomato and cucumber. In Spain, almost all watermelon are grown from grafted plants.

Grafting is ideally suited for developing countries, the researchers say, as the technique does not require expensive kit or expertise. They described Capsicum anuum  as “priceless plant material” for the sustainability of pepper farming.

However, there are costs implications to the technique, says James Nienhuis, a plant breeding researcher at the horticulture department of the University of Wisconsin-Madison in the United States. He points out that in Costa Rica, for example, a conventional seedling costs around $0.20, but a grafted seedling could cost up to $0.75. This is because the grafted plants require extra work, and result in half of each plant being thrown away.

“But, the extra cost of the seedling is saved easily by eliminating the need to purchase and apply chemicals to control soil pathogens and also by the dramatic increase in yield,” he says. Nienhuis cites the example of a project he worked on in Totonicapan, Guatemala, where a women’s cooperative managed to up the yield of their tomato harvest by 50 per cent by grafting plants onto the roots of varieties that are resistant to pathogens in the soil.

The grafting technique is also used to protect plants against pests, which decreases the need for expensive pesticides. In South Asia, Edwin Rajotte, a professor of entomology at Penn State University in the United States, has studied grafting as a means to combat bacterial wilts in eggplant and pepper plants. However, he warns that grafting loses its power over time.

“Over time, pests can evolve to overcome root resistance,” he explains. “Grafting should be a component of an extensive integrated pest management approach.”

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