India - Nipping the rust in the bud

The wheat crop the world over is under threat from a new scourge that is spreading fast across continents. It is essentially a new strain of wheat stem rust that is the most virulent and destructive of all forms of rusts that have plagued this key food crop in past 50 years. Called Ug99 because it was first observed in Uganda in 1999, this dreaded disease has covered considerable distance eastwards of Africa to reach as far as Iran.
India is not wholly insusceptible to it but we have, fortunately, already taken protective steps. For this, several well-conceived precautionary measures have been taken by the Indian Council of Agricultural Research (ICAR).
“This infection has not been noticed anywhere in the country till now and we are fully prepared to prevent its entry. Even if it manages to sneak in, it will be contained there and then”, asserts P L Gautam, ICAR deputy director-general (crop sciences).
In fact, work on locating the sources of Ug99-resistant genes and breeding disease-immune varieties had begun way back in 2004. India, among the world leaders in wheat research, had been instrumental in roping in the global wheat research community, including Nobel laureate Normal Borlaug, hailed as the father of the wheat revolution, to forge an international collaboration to arrest the spread of this deadly rust.
Besides being one of the core members of the Global Rust Initiative, India is also among those who are funding it. The combat against Ug99 stem rust got a big shot in the arm when the Bill and Melinda Gates Foundation announced in last April a donation of $26.8 million to breed new rust-tolerant wheat strains over the next three years.
The global strategy to contain this peril involves development as well as introduction of disease-resistant wheat varieties throughout the migration path of this rust. This will help reduce the build-up of the pathogen and, consequently, curtail the chances of its spreading to newer areas.
The Indian strategy to deal with this menace is even more elaborate and has already made good progress. The 43rd annual wheat researchers’ workshop held in August 2004 had decided to start identifying sources of resistance against this disease and exploring the fastest means of incorporating those genes into the Indian wheat varieties. Since this rust thrives well in Kenya — and also to rule out any chances of this infection being carried to the Indian wheat fields — India started a programme to test wheat material at Njoro in Kenya.
The tests conducted at Njoro have begun delivering results. These have confirmed that many Indian wheat varieties are already immune to Ug99 stem rust and its variants. What is particularly reassuring is the presence of diverse resistance in some of these varieties that will help fight not only the Ug99 but other future threats of this magnitude as well.
Going a step further, India has begun multiplying Ug99-resistant wheat germplasm and providing it to wheat breeders for further research and incorporation into various wheat varieties. Significantly, in 2007-08 itself, more than 4,000 quintals of breeder seeds of 11 such wheat varieties were produced. Besides, another Ug99-resistant variety, Raj 4120, was identified by the national wheat workshop, held last month in Hissar, for commercial cultivation.
In addition to these measures, arrangements have been made for regular surveys of wheat fields in the potentially-threatened areas to detect the infection without any delay in the rare event of its appearance in the country. This will enable resorting to the use of chemicals to kill the infection there and then and also to promote the use of rust-protected varieties in and around those places.
A special team of experts has been constituted to survey and monitor the wheat fields in the upper reaches of Himachal Pradesh, Jammu and Kashmir and the Nilgiri and Paliny hills in the south where wheat is cultivated in summer, which otherwise is the off-season for wheat in its main growing areas of the northern plains. This will help break the cycle of multiplication of spores of the rust that carry the infection to distant places through air and clouds. A similar strategy was deployed successfully to contain wheat rusts in the late 1970s.
Such a multi-pronged approach to keep the country free of this menace is a clear indication that Indian farm scientists are unlikely to lose the battle against this disease.