Killer fungus threatens Asian breadbasket

A killer fungus commonly known as Ug99 (Uganda-99) destroyed Iranian wheat fields in the 2008 wheat season. Wheat crop suffers from three types of rust diseases: Brown, yellow and black or stem. Of the three rusts, black rust was under genetic control globally since the last five decades. However, it remained as an endemic problem in east Africa (Uganda and adjoining countries). It was in 1999, a mutated form of black rust pathogen suddenly evolved in Uganda, scientifically designated as TTKS and commonly known as Ug99, which destroyed all Ugandan wheat fields the following season. Stem rust is a catastrophic disease because of its ability to cause complete annihilation of wheat crops over wide areas. The rust fungus produces numerous tiny spores and migrates from one country to another with the help of winds.

The deadly pathogen followed the Puccinia path (a well-defined route through which rust pathogens moved from Africa to Asia in the past) and spread in Ethiopia and Kenya in 2002. It destroyed all wheat fields in Yemen in 2006 and strong winds during February, 2008, blew the pathogen into the Arabian Peninsula invading wheat crops in Iran. From Iran, it can enter into Afghanistan, Pakistan, India and ultimately into Nepal any time and disrupt the Asian breadbasket.

Ug99 can enter Afghanistan, Pakistan, India and ultimately into Nepal any time.

The UN Food and Agriculture Organization (FAO) warned in a statement on March 5, 2008 that entire wheat-growing fields in western Iran were threatened by Ug99. It also sounded alerts to six countries, including India, about the dangerous fungus.

“Global wheat yields could be at risk if the stem rust spreads to major wheat-producing countries,” Dr Jacques Diouf, FAO director-general, said in a recent statement.

Noble Peace laureate and father of green revolution, Dr N E Borlaug, said that “stem rust is a catastrophic disease because of its ability to cause complete annihilation of wheat crops over wide areas and if we fail to contain Ug99 it could bring calamity to tens of millions of farmers and hundreds of millions of consumers.” He further reiterated that “we know what to do and how to do it. All we need are the financial resources, scientific cooperation and political will to contain this threat to world food security.”

The yield loss due to Ug99 may reach as high as 100 percent if we cannot replace currently grown wheat varieties from farmers’ fields. To combat Ug99 problem, countries such as India, Pakistan and China started an emergency crash program to breed resistant wheat varieties and replacement of susceptible ones from the wheat growers.

The problem is that crop breeding is slow. It usually takes at least five years to cross disease-resistant lines with wheat varieties adapted to local conditions in the world’s wheat-growing countries and then grow enough seeds to plant fields threatened by Ug99.

National Wheat Research Program (NWRP), Bhairahawa, has also initiated a breeding program to develop and identify Ug99 resistant seeds but the progress is rather slow due to the lack of sufficient resources. We have resumed off season shuttling of segregating populations to speed up breeding cycle and seed production of identified resistant seeds in a high altitude site named as Marpha horticulture farm, Mustang, from 2009 summer season so that enough seeds can be produced twice in a year and distributed before the killer fungus enters into the Indian sub-continent. NWRP is likely to release a resistant strain of wheat before the end of 2009. However, it will take at least three to four years to take this resistant variety of seeds to a large number of farmers.

(Writer is national wheat coordinator of National Wheat Research Program, Bhairahawa.)