The rust resistant variety (right)

IITA

[LAGOS] A variety of soybean resistant to a devastating Asian rust will soon be widely available in West and Central Africa. The rust, a fungal disease that entered Africa in 1996, can wipe out 80 per cent of infected crops.

Scientists from the International Institute of Tropical Agriculture (IITA) in Nigeria and the country's National Cereals Research Institute (NCRI) developed the rust-resistant variety, named TGX 1835-10E.

They say it will drastically reduce the rust problem as it has resistance genes for all known types of rust in Nigeria.

"The [rust resistant] variety can be used for direct cultivation in tropical Africa or as a source of resistance genes in soybean breeding programmes," says IITA soybean breeder, Hailu Tefera. "It was previously released in Uganda by Makerere University and has also already shown excellent performance in trials carried out in southern Africa."

Nigeria, South Africa and Uganda are the largest producers of soybean in Africa, according to the UN Food and Agriculture Organization.

In 1999, farmers in southwest Nigeria found the leaves of their immature soybean crop rapidly turning brown and falling off, leaving only straggly stems. Tests confirmed the cause was the rust fungus, Phakopsora pachyrhizi.

The breakthrough is important because farmers can plant the new variety without applying expensive anti-rust chemicals. In 2003 — just two years after Asian rust arrived — Brazil lost US$2 billion in soybean harvests despite spending US$400 million on fungicides.

"The new cultivar does not solve the general problem of [all] fungal disease on plants but it does provide relief to farmers faced with the challenges of rust disease without any other solution," Olumide Shokalu, the NCRI pathologist who led trials, told SciDev.Net.

He says the seeds will be available to farmers by the start of the new cropping season in 2010. The National Agricultural Seed Council and NCRI are producing stocks for distribution, at a token price, through certified seeds outlets.

But Nasiru Ibrahim, of the department of agriculture at Nigeria's Usmanu Danfodiyo University, sounded a note of caution: "Methods of pest or disease control only work for some time and need periodic review. Pests or disease develop new strains to break whatever resistance is in place.