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Archive for the ‘Fungi’ Category

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  • GM banana resistant to fungus shows promise

[KAMPALA] A banana strain resistant to a common fungal disease could help smallholder farmers in East Africa better control the crippling disease, which has been spreading across the region over the last three decades.

The results of confined field trials of a genetically modified (GM) banana with improved resistance to a black sigatoga disease, the devastating leaf spot fungus, are promising, researchers have told SciDev.Net.

The disease is caused by the fungus Mycosphaerella fijiensis and it can halve fruit production in affected plantations. It is easily spread by airborne spores, rain, planting material, irrigation water and packing material used in transporting goods between banana-growing countries.

The dark leaf spots caused by the fungus eventually enlarge and merge together, causing much of the leaf area to dry.

The team led by Andrew Kiggundu — head of banana biotechnology research at the Uganda’s National Agricultural Research Laboratories Institute (NARL) in Kawanda — analysed 19 lines of GM bananas and found promising results in five of them. Andrews told SciDev.Net further research is needed to calculate the exact yield gains from using the resistant banana strain.

The researchers inserted genes for chitinase — an enzyme that breaks down chitin, the hard substance that makes up the cell walls of the invading fungi — preventing the fungus from invading the plant cells and causing the disease.

Kiggundu said laboratory tests using leaves from transgenic plants showed almost full immunity when cultured fungi were applied to the leaves.

Researchers collaborated closely with the Catholic University of Leuven in Belgium, where several banana lines were engineered to include the chitinase gene before being brought to NARL for testing.

However, Settumba Mukasa, resident banana expert in the department of crop science at Uganda’s Makerere University, said the field trials had more significance for building research capacity in Uganda than the development of a new disease-resistant banana.

“[The project] is a stepping stone for subsequent breeding programs and genetic engineering programmes. As a consequence of this project we can now do transformations of other varieties of bananas and other crop species,” said Mukasa.

While black sigatoka is among the top three diseases affecting bananas in Uganda it mainly affects Cavendish, which are not as widely cultivated as other types of bananas.

But for the few farmers in Uganda who do grow Cavendish bananas, the development may be useful since the disease is currently controlled by aerial pesticide spraying which is expensive for smallholders and affects their health.

“Farmers cannot afford that because they are small and they have few plants. Here, chemical control is not viable, so this approach may be the only available method to manage the disease,” Mukasa said.

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  • Fungus-resistant gene found in rice

   

Scientists in Japan have found a way to create high-yielding rice with long-lasting resistance to the devastating rice blast fungus.

Sufficient rice to feed 60 million people is destroyed by the blast fungus, Magnaporthe grisea — also known as Magnaporthe oryzae — every year.

Some rice is naturally resistant but is often also of lower yield. Now a team led by Shuichi Fukuoka from the National Institute of Agrobiological Sciences in Japan has engineered good quality rice that is both resistant to blast disease and high-yielding.

Their research was published in Science last week (21 August).

By comparing japonica rice that is resistant to blast disease with rice that succumbs to infection, Fukuoka found that a change in a key gene called Pi21 can mean the difference between devastating infection and mild disease.

Fukuoka says even plants with the resistant form of the gene become infected, but “The damage they suffer is not so serious, making it possible to reduce the amount of fungicide used by 50 per cent.”

He says his team’s findings will be particularly useful in mountainous areas where blast disease is a serious threat.

There have been many previous attempts to engineer resistant rice strains by making specific adjustments to plant immunity to allow the plants to recognise and resist the fungus.

But according to Nick Talbot, professor of molecular genetics at Exeter University in the UK, many of these modifications have a field life of just 2–3 years, as the fungus is quick to find ways to circumvent them and avoid being recognised.

Having the resistant form of Pi21, however, means a plant increases its defences against infection in general, making it much harder for the blast fungus to find a way to take hold, says Talbot.

He says the Japanese researchers have made a big discovery with universal applicability. When this is combined with other methods of engineering rice, scientists may be in a position to “exclude blast infections in a durable manner”.

Fukuoka has also managed to isolate the resistant form of Pi21, meaning it can be separated from other genes associated with poor yield. Previously this has been difficult because when scientists have tried to transfer the resistant Pi21 gene into new strains of rice, the genes affecting quality have also hitched a ride.

Fukuoka says the fact that his research has shown the exact location of the Pi21 gene means scientists can ensure it is not replaced by a more vulnerable form when breeding new rice strains.

Link to full article in Science

 

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12:00 AM, March 01, 2016 / LAST MODIFIED: 03:44 AM, March 01, 2016

‘Wheat blast’ threatens yield

Farmers in 6 districts complain of infection

Wheat blast disease has become a serious threat to grain quality and yield, incurring losses to the farmers in six southwestern districts.

Scientists and specialists after laboratory tests claimed that this is the first time in Bangladesh in which the seasonal crop got infected with this disease.

Officials at the Department of Agricultural Extension (DAE) and Wheat Research Centre (WRC) of the Bangladesh Agricultural Research Institute said they have examined samples from the fields and confirmed that the disease is a blast infection.

They identified the fungus that might have grown due to unexpected temperature fluctuation and several days of continuous rain in the first week of February.

Experts also have tested the seeds used to be sure of the infection, the officials said.

The affected districts include Kushtia, Meherpur, Chuadanga, Jhenidah, Jessore, and Magura.

DAE officials, who visited the affected fields, said Meherpur was the badly hit. Around 2,000 hectares of wheat fields had been damaged by the fungus.

According to farmers, they have marked yellow and black spots on the leaves and sheaves of wheat. After a few days, the spots got larger and spread over the entire plant.

At one stage, both the sheaves and flowers turned yellow and white, and finally the plant dried up without producing any grain.

Mustafizur Rahman, deputy director of Meherpur DAE, said farmers started informing them about the matter from mid-February.

“We told the higher authorities about the problem after visiting the fields,” he said.

A team, led by Paritosh Kumar Malaker, chief scientific officer of Wheat Research Centre in Dinajpur, visited the affected fields in Meherpur, Chuadanga, and Jhenidah on Wednesday.

“We have made pathogen tests using the diagnostic technique, called ‘field pathogenomics’, and confirmed the symptoms of the disease,” he said.

He said, “As it [disease] is the first infection in Bangladesh, we need to be more careful.”

Farmers and DAE officials said the areas experienced rain in the first week of February. After five to seven days, farmers observed spots on wheat leaves and sheaves.

This correspondent visited Garadoba, Saharbati, Dhankhola, Bamundi of Gangni upazila, and Khoksa, Chandbeel, Madandanga in Meherpur Sadar upazila and found a large number of affected fields.

Farmers Ripon and Mawla Boksh of Madandanga told this correspondent that they jointly cultivated wheat on five bigahs of land. About half of the crop was damaged. They have to incur a huge loss, they said.

Sources at the DAE divisional office in Jessore said farmers in the six southwestern districts cultivated wheat on around 58,135 hectares. Some 16,710 hectares are in Kushtia, 10,320 hectares in Jhenidah, 7,020 hectares in Magura, 5,810 hectares in Chuadanga, 4,400 hectares in Jessore and 13,875 hectares in Meherpur.

Mustafizur Rahman, deputy director of Meherpur DAE, said they were holding meetings with the farmers and distributing leaflets to create awareness among the farmers.

The DAE office also advised the farmers to spray Nativo and Folico on the affected fields.

He primarily estimated that 5 percent of the total production might be affected.

However, Chief Scientific Officer of WRC Paritosh Kumar said wheat production would decrease by around 10-40 percent.

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Florida Farmers Adapting to UF/IFAS Web-Based Tool to Ward Off Strawberry Diseases

Released: 16-Feb-2016 8:05 AM EST
Source Newsroom: University of Florida Institute of Food and Agricultural Sciences

 

Newswise — GAINESVILLE, Fla. — Farmers are adapting to a UF/IFAS-developed, web-based monitoring system that can help the environment by using less chemical treatment to prevent strawberry diseases, which will help the state’s $306 million a year crop, a new UF/IFAS study shows.

The web-based tool, known as the Strawberry Advisory System (SAS), uses data such as temperature and leaf wetness to tell growers when to spray fungicide to ward off diseases.

“Overall, the results show evidence of potential economic gains from switching from calendar to certain SAS-based options,” said post-doctoral researcher Theodoros Skevas, who led the study.

Most strawberry growers treat for fungi every week. Natalia Peres, a UF/IFAS associate professor of plant pathology, helped develop the SAS in 2012 to give producers more precise times to chemically prevent two potentially deadly fungi. The SAS has two models, one to help farmers control Botrytis and the other to prevent anthracnose – two fungi that make the fruit rot.

For a new study published in the journal Crop Protection, the team of University of Florida Institute of Food and Agricultural Sciences researchers examined the economic effects of traditional, calendar-based chemical treatments of strawberries and compared them to variations of the SAS, using different chemicals.

In order to compare the calendar-based system and the web tool, Skevas used production yields and costs, and historical strawberry prices (i.e. from 2000 to 2015) to construct simulated budgets. The historical strawberry prices helped to account for price volatility when measuring the economic performance of the calendar and SAS-based systems with different chemical treatments. They found that treatments following SAS recommendations with some products posed no greater risk than applying fungicides weekly. But, the risk and economic performance depended on the choice of product used.

A UF/IFAS study published in 2014 showed the SAS can bring growers $1.7 million more in net profits over 10 years than a calendar-based fungicide system because it guides growers to spray their crop at optimal times. Skevas said the latest study offers more precise product recommendations on which SAS-based systems growers would have better economic performance and reduced risks under different botrytis fruit rot conditions.

Peres and Zhengei Guan, an assistant professor of food and resource economics, supervised Skevas’ research. All three conduct research at the UF/IFAS Gulf Coast Research and Education Center in Balm, Florida.

Before SAS was developed, strawberry farmers traditionally sprayed weekly during the November-to-March growing season. Spraying more often than needed increases production costs and can lead to fungicide resistance, Peres said.

By: Brad Buck, 352-294-3303, bradbuck@ufl.edu
Sources: Theodoros Skevas, 813-633-4128, skevast@ufl.edu
Natalia Peres, 813-633-4133, nperes@ufl.edu

 

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Uganda’s First Field Observation of GM Potato Shows Extreme Resistance to Late Blight

The first field trial of genetically modified (GM) potatoes resistant to potato blight conducted in Uganda from October 2015 to January 2016 has been completed at the Kachwekano Zonal Agricultural Research and Development Institute (KaZARDI) of the National Agricultural Research Organization (NARO) near Kabale.

Twelve highly resistant GM potatoes of ‘Desiree’ and one of ‘Victoria’ varieties from the International Potato Center (CIP) showed extreme levels of resistance compared to the non-GM plants of the same varieties. Using genetic transformation, three resistance (R) genes from wild relatives (Solanum bulbocastanum, and S. venturii) were transferred into farmers’ preferred varieties and the results are encouraging. A number of partially resistant varieties exist, but these are not preferred by farmers and consumers. This first observation of zero-fungicide potatoes marks an important milestone in the development and future deployment of biotech potato varieties to farmers in Africa that will significantly reduce losses and cost of production.

In Uganda, losses due to potato late blight can reach up to 60%, forcing farmers to spray fungicides up to 15 times to protect their crops. About 300,000 smallholder households grow potatoes for their subsistence living and income generation. Losses due to late blight represents between 10-25% of their revenue from potato.

For more details about this project, contact Dr. Andrew Kiggundu/NARO (akiggundu@kari.go.ug), or Dr. Marc Ghislain/CIP (m.ghislain@cgiar.org).

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Coffee farmers ask govt help to control CLR

By Yogesh Pokharel, Kathmandu, Jan. 10: Coffee farmers and stakeholders have warned that Nepali coffee might be wiped out within a few years from now if no urgent steps were taken to protect it from the endemic coffee leaf rust.

The coffee leaf rust (CLR) is a disease caused by a fungus, Hemileia castatrix, and is SPREADING in many coffee producing districts and has destroyed several coffee orchards in Nepal.

Talking to The Rising Nepal, Prachanda Man Shrestha, chairperson of Beautiful Coffee Nepal, said that the rust had widely destroyed the coffee plants in many districts in Nepal and demanded urgent steps to control it.

“Though coffee rust was identified recently, it had already spread in many coffee orchards of Nepal,” he suspected.

“Nepali coffee farmers even do not have expertise what step to take next to protect our coffee from it,” Shrestha said and added that the concerned stakeholders should work to find immediate solution or it would be too late to protect Nepali coffee.

He asked the concerned stakeholder to take prompt action with expert’s advice to control the rust.

“There is an urgent need of bringing experts to help suggest what steps to take in such a situation,” he said.

Bal Bahadur KC, former chairman of District Coffee Cooperative Union, Lalitpur, said that the endemic rust has posed serious threat to the coffee in the district.

“The rust has destroyed more than 75 per cent coffee trees in Durlung Organic Coffee Cooperative and affected all the coffee producing areas of the district,” he said.

Thuladurlung, Gimdi, Chandanpur, Pyutar and Kamidanda are major coffee producing village development committees (VDCs) in Lalitpur district.

He said that coffee production has reduced by more than 50 per cent and warned that the plants would be totally eliminated within next five years if urgent steps were not taken to project Nepali coffee from this disease.

He said that the production of coffee had fallen sharply owing to the infection of White Stem Borer and suspected that the endemic coffee leaf rust might eradicate Nepali coffee.

Lalitpur district would produce more than 62 metric tonnes of dry parchment coffee. However, the production has fallen down to less then 20 metric tonnes dry parchment in 2015.

Coffee rust was officially identified in Nepal in April 2015. However, the disease had severely affected many coffee orchards in Lalitpur and other districts in the country.

Meanwhile, the National Tea and Coffee Development Board (NTCDB) has formed a team under its coordination to curb the transmission of the endemic rust and devise necessary measures for its control and management.

“We have formed a team including representatives from all stakeholders and institutions working with coffee to take immediate step for the control and management of the disease,” Raghupati Chaudhari, Deputy Executive Director at the NTCDB, said.

He informed that the team would request Nepal Agricultural Research Council, Ministry of Agriculture Development and other organisations for it.

He said that the disease was reported to have damaged coffee in Lalitpur, Kavre, Syanja and Kaski districts.

The chances of the transmission of the disease in other parts of the country is equally high as the disease transmits through air.

Coffee is one of the major emerging cash crops in Nepal. Nepal produces around 450 metric tonnes green beans coffee annually, almost 70 per cent of which is exported.

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12:00 AM, January 20, 2016 / LAST MODIFIED: 12:00 AM, January 20, 2016

Thakurgaon, Panchagarh

Potato growers of Thakurgaon and Panchagarh districts are worried due to attack of late blight disease at different villages of the two northern districts.

Leaf blight is a fungal disease, locally known as ‘patamora rog’. If immediate steps are not taken, leaves of the affected plants crumple, turn blackish, and die shortly, said Arshed Ali, deputy director of the Department of Agriculture Extension (DAE) in Thakurgaon.

“The disease appeared due to cold and foggy weather and fluctuation in temperature between day and night. To check the disease, we are suggesting farmers to spray on their potato fields two gram of Mencozeb or Metalexyl medicine mixed with one litre of water once a week,” he said.

He claimed that the situation is still under control.

During a recent visit to Yakubpur, Farabari, Chameshwari, Balia and Rahimanpur villages under Thakurgaon Sadar upazila and Moidandighi, Sipaipara and Sakoa villages in Boda upazila of Panchagarh district, this correspondent saw many late blight affected potato fields.

Frequent use of medicine adds to the production cost, said several farmers, who were seen spraying medicine to save the crop.

“I cultivated potato on two bighas (one bigha = .3306 acres) of land, spending about Tk 60 thousand, but a portion of the plants got damaged by the disease. As per suggestion of experts, I sprayed medicine on the field to save the remaining crop,” said Koileshwar Barman, 35, of Yakubpur village.

He had also incurred loss of Tk 45,000 by cultivating early variety of potato as the seeds rotted after 20/25 days of sowing seeds, he said, adding that many other early potato growers of the area faced the same this season.

This season 23,080 hectares of land has been brought under potato cultivation against the target of 21,800 hectares in Thakurgaon while in Panchagarh, the cultivation area is 8,680 hectares of land against the target of 9,505 hectares.

The DAE had set production targets of 4.38 lakh 370 tonnes and 1.86 lakh 773 tonnes of potato in Thakurgaon and Panchagarh districts.

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