Plant breeders urged to develop drought-tolerant GM crops

Plant breeders have been challenged to develop genetically modified (GM) crops that are relevant to the needs of developing countries, especially in light of the effects of climate change.

Agricultural experts are concerned that most of the GM crops so far developed are not best suited to address the serious challenges of climate change in developing countries.

Most genetically modified (GM) crops being cultivated today were developed to be herbicide tolerant and resistant to pests. Development of GM crops with traits valuable for poor farmers, especially within the context of climate change - such as resistance to drought, extreme temperatures, soil acidity and salinity - is not yet a reality, states Dr. Jacques Diouf, Director-General, Food and Agricultural Organisation of the United Nations (FAO).

"I cannot sufficiently underline the need to also address the needs of resource poor farmers in rain fed areas and on marginal lands," says Diouf. He states that science and technology must spearhead agricultural production in the next 30 years at a pace faster than the Green Revolution did during the past three decades. Exploiting the new biotechnologies, including in particular in vitro culture, embryo transfer and the use of DNA markers, can supplement conventional breeding approaches, thus enhancing yield levels, increasing input use efficiency, reducing risk, and enhancing nutritional quality, he said.

Diouf warns that climate change is likely to undermine food production in the developing world, while industrialised countries could gain in production potential.

Crop yield potential is likely to increase at higher latitudes for global average temperature increases of up to 1 to 3°C depending on the crop, and then decrease beyond that, he said. On the contrary, at lower latitudes, especially in the seasonally dry tropics, crop yield potential is likely to decline for even small global temperature rises, which would increase the risk of hunger. Greater frequency of droughts and floods would affect local production negatively, especially in subsistence sectors at low latitudes. Rain fed agriculture in marginal areas in semi-arid and sub-humid regions is mostly at risk, warns Diouf.

Ren Wang, the new director for the Consultative Group on International Agricultural Research (CGIAR), further warns that climate change and biofuels pose fresh challenges in the fight against poverty, which requires more than ever, cooperation among scientists. He said new crop varieties, such as drought-resistant rice, were crucial for securing food supply, especially as populations continue to grow.

Dr. Stephen Mugo, a maize breeder with the International Maize and Wheat Improvement Center (CIMMYT) agrees that there is need for more emphasis on drought tolerant crop varieties. Drought tolerance is a trait that will have the greatest impact in countries that have continued to experience higher and more severe incidences of droughts, he says.

While CIMMYT is currently conducting trials on GM maize resistant to maize stem borers in Kenya. However, despite the urgency for drought-tolerant crops to counter effects of climate change, CIMMYT is not intending to start developing a GM maize variety that is tolerant to drought.

But Professor Norah Olembo, executive director, African Biotechnology Stakeholders Forum believes that pest damage is a bigger problem than drought, and that scientists are justified to concentrate on developing crop varieties resistant to major crop pests in the region. She argues that pest infestation, now ravaging 50 per cent of crops both in field and storage, is a more current issue than climate change. "Climate change is a gradual phenomenon. Droughts have been there ever since. But pest issues are current. Scientists must address current constraints with current traits," argues Olembo.

Realizing that modern biotechnology may not provide maize varieties that are resistant to drought, Bill and Melinda Gates Foundation has initially given CIMMYT US$5 million towards the Drought Tolerant Maize for Africa project. The project is to develop drought-tolerant maize using conventional methods. Mugo explains that the funds are for the development of facilities.

While genetic engineering had potential for the future, conventional technology was likely to remain in the mainstream for the next 5-10 years.

The Standard-Kenya