However, the wheat scientists have not given up. They have conceived another route to achieve a similar - or even more spectacular - leap in productivity. It involves elevating the photosynthetic capacity of the wheat plant to enable it to utilise solar energy more efficiently to bear larger number of relatively bulkier grains. The Mexico-based International Maize and Wheat Research Institute (abbreviated to CIMMYT in local language), where Borlaug bred his miracle wheat strains over half a century ago, is now endeavouring to pierce the productivity barrier through this approach. CIMMYT Director-General Thomas A Lumpkin seems confident that this strategy can lift the wheat yield ceiling by 50 per cent. "But the task is huge because wheat plant needs to be reworked and modified to enable it cope with higher photosynthetic capacity that requires accommodating more energy for higher grain production," he cautions. It is like remodelling a car to make it compatible with a higher horsepower engine.
The Mexican institute intends to move some of the work on this project to this part of the world by roping in the Borlaug Global Rust Initiative (BGRI) which has a close collaboration with the Indian Council of Agricultural Research (ICAR). The BGRI is working primarily on trimming the world's vulnerability to rust that has for long been the nemesis of wheat, taking a heavy toll on crop output across the world. It is funded largely by the Bill & Melinda Gates Foundation and the UK's Department of International Development.
Newer forms of rust infection keep surfacing, exacerbating this menace. The latest and the most perilous among the relatively newer forms of rust is the stem rust Ug99 - called so because it was first noticed in Uganda in 1999. It has spread rapidly to several countries and is now playing havoc in wheat farms in east Africa, Yemen, Iraq and, to some extent, Iran. Incidence of rust have also been observed recently in India's neighbourhood, notably Pakistan and Afghanistan, which hopefully would be contained there. Globally, nearly 85 per cent of wheat grown in the Americas, Asia and Africa is susceptible to the Ug99 stem rust.
Though India has successfully kept rust under control for the past few decades by evolving and putting into cultivation rust-immune wheat varieties, the danger of rust invasion cannot be ruled out. Indian wheat scientists, therefore, intend to saturate the wheat area with Ug99-protected varieties. Going by ICAR Director-General S Ayyappan's statement, the area planted with highly Ug99-susceptible wheat variety PBW-343 has been reduced in the past five years from over half of the country's total wheat acreage to just a quarter now. All new wheat varieties are now screened and tested for immunity against Ug99 in rust endemic countries such as Kenya and Ethiopia with the help of the BGRI.
Thus, enhancing the innate yield potential of wheat by improving its photosynthetic efficiency may be of little consequence unless the scientists also simultaneously address scourges such as rust and other stress caused by climate change and receding water table, especially in South Asia's sprawling wheat granary spanning India, Pakistan and Nepal. The global combat against enemies of wheat requires unflinching scientific cooperation among all wheat growing countries which, unfortunately, is not forthcoming in full measure. Farm scientists from across the world gathered recently in New Delhi to attend a technical workshop on wheat, organised by the BGRI in collaboration with the ICAR, expressed disquiet over the hurdles being put up by some countries in free flow of biological research material. India favours free sharing of such material with other countries. Unless the others do the same, scientists may remain handicapped in their war against wheat stress.
surinder.sud@gmail.com