To ease your site search, article categories are at bottom of page.

June 13, 2010

Genetic mutations increase global risk of deadly wheat stem rust

by Joe DeCapua

Scientists are warning of a new threat to the world’s wheat crops. They say there are four new genetic mutations of Ug99, a strain of a wheat pathogen known as stem rust.

The mutations of the reddish-brown fungus called races are overcoming existing genetic resistance that was developed to safeguard wheat crops. Stem rust can spread very quickly by the release of spores.

Wheat experts from around the world met recently in St. Petersburg, Russia. One of them is Dr. Hans-Joachim Braun, director of the Global Wheat Program at the Mexican-based International Maize and Wheat Improvement Center.

“The concern,” he says, “is that stem rust is historically the most important disease of wheat. And that’s why it got a lot of attention some 50 years ago when breeders successfully developed stem rust resistant varieties,” he says.

Then, in 1999, Ug99 was discovered in Uganda and later in Kenya, Ethiopia, Sudan, Yemen and Iran. It’s blamed for an 80 percent loss of Kenyan Farmers wheat during several seasons.

“We didn’t have a stem rust epidemic for nearly 50 years, from 1953 until the late 90s, when a new stem rust race was identified in Uganda. And it turned out that this new stem rust race was virulent on more than 90 percent of all currently commercially grown cultivars,” he says.

A cultivar is a plant deliberately selected for its characteristics, such as color, crop yield or disease resistance.

Scientists knew that if Ug99 spread, it could have devastating effects on grain baskets around the world.

Efforts to breed disease resistant wheat were very successful, but that success may have dulled awareness of the threat of stem rust. But Braun says scientists knew that mutations could happen.

“For 45 years we had very, very little problems. And so in most countries, breeding for stem rust resistance was de-emphasized. And when Ug99 occurred there were less than 10 stem rust specialists still working and active around the world,” he says. “It was basically complacency, but not so much on the scientists’ side. They were aware it could happen, but it was really an issue of funding.There are now very good monitoring systems in place to make sure that if there is an outbreak somewhere that we can react very fast,” Braun says.

Breeders are trying to stay a step ahead of stem rust mutations by growing more disease resistant varieties of wheat. Samples are sent to Kenya for evaluation.

“Annually, about…45,000 potentially new wheat varieties are sent to Kenya. And then the scientists go to Kenya and evaluate the material and identify the lines which are resistant,” he says.

Scientists are also looking for plant resistance genes that could be bread into varieties of wheat.

“At present, breeding for stem rust resistance is a top priority for many, many breeding programs around the world,” says Braun.

While stem rust is not harmful to humans, Braun says there could be “a major disaster” if a stem rust epidemic were to break out in a major wheat growing area of the world, such as in the Punjab region of Pakistan and India.

Scientists say the evolving pathogen may pose an even greater threat to global wheat production than the original Ug99.

VOA

Article Categories

AGRA agribusiness agrochemicals agroforestry aid Algeria aloe vera Angola aquaculture banana barley beans beef bees Benin biodiesel biodiversity biof biofuel biosafety biotechnology Botswana Brazil Burkina Faso Burundi CAADP Cameroon capacity building cashew cassava cattle Central African Republic cereals certification CGIAR Chad China CIMMYT climate change cocoa coffee COMESA commercial farming Congo Republic conservation agriculture cotton cow pea dairy desertification development disease diversification DRCongo drought ECOWAS Egypt Equatorial Guinea Ethiopia EU EUREPGAP events/meetings exports fa fair trade FAO fertilizer finance fisheries floods flowers food security fruit Gabon Gambia gender issues Ghana GM crops grain green revolution groundnuts Guinea Bissau Guinea Conakry HIV/AIDS honey hoodia horticulture ICIPE ICRAF ICRISAT IFAD IITA imports India infrastructure innovation inputs investment irrigation Ivory Coast jatropha kenaf keny Kenya khat land deals land management land reform Lesotho Liberia Libya livestock macadamia Madagascar maize Malawi Mali mango marijuana markets Mauritania Mauritius mechanization millet Morocco Mozambique mushroom Namibia NEPAD Niger Nigeria organic agriculture palm oil pastoralism pea pest control pesticides pineapple plantain policy issues potato poultry processing productivity Project pyrethrum rai rain reforestation research rice rivers rubber Rwanda SADC Sao Tome and Principe seed seeds Senegal sesame Seychelles shea butter Sierra Leone sisal soil erosion soil fertility Somalia sorghum South Africa South Sudan Southern Africa spices standards subsidies Sudan sugar sugar cane sustainable farming Swaziland sweet potato Tanzania tariffs tea tef tobacco Togo tomato trade training Tunisia Uganda UNCTAD urban farming value addition value-addition vanilla vegetables water management weeds West Africa wheat World Bank WTO yam Zambia Zanzibar zero tillage Zimbabwe

  © 2007 Africa News Network design by Ourblogtemplates.com

Back to TOP