Sunday, May 11, 2014

On the promise of genetic engineering to improve rice varieties.

Five years after the first field trials, 5m farmers across the world are planting more than a dozen varieties of rice with flood-resistant genes, collectively called “Sub 1”. They are proliferating even faster than new rice varieties during the heady early days of the first green revolution in the 1960s.
The Economist

The current issue of The Economist has a very good article on the use of genetic engineering in the effort to meet the growing demand for food. Here are some quotes from the article:

  1. As a rule of thumb, if the world’s population grows by 1 billion, an extra 100m tonnes of rice is required to feed them. Given current world-population forecasts, total rice consumption, now under 450m tonnes, is likely to grow to 500m tonnes a year by 2020 and to 555m by 2035—an increase of 1.2-1.5% a year. That would be manageable if rice yields were also growing at that rate. But they are not. They are rising at barely half that pace.
  2. Now the gains seem to have levelled off. Plant breeders fear that, with current technology, ten tonnes a hectare for rice in intensive-farming systems may be the limit, though it is not clear why. What is clear is that, out in the fields, output per hectare is stalling, and in some places falling.
  3. Without new seeds, yields will decline further. Global warming will tend to push harvests down: higher night-time temperatures are associated with lower yields. The richest rice-growing areas in the world are the deltas of Asia’s great rivers, such as the Mekong, Brahmaputra and Irawaddy; they are vulnerable to rising sea levels and increased salinity, which kills rice. The plant uses two to three times as much water as other cereals ........but water is scarce everywhere. 
  4. (To meet the demand for more rice) researchers will tailor seeds (utilizing genetic engineering) for particular environments (dry, flooded, salty and so on). And they are also trying to boost the nutritional quality of rice, not just the number of calories.
  5. Drought- and flood-tolerant seeds could double yields from these areas (where rain fed rice is grown). That would boost harvests from 110m tonnes to 220m, and push global output to 550m tonnes—enough to meet expected demand in 2035. In short, all the extra rice could come from rain-fed areas alone.
  6. The original green revolution transformed Asia from a continent stalked by hunger into one that could think and plan beyond the next harvest. It helped lay the foundation for the continent’s economic miracle and made possible Asia’s demographic transition from high fertility and high mortality to smaller, richer families. The second green revolution will not do that. But it should complete the first one, mainly by bringing benefits to the poorest, who missed out first time round. It will help mechanise and move more people off farms and into more productive labour. And it should prevent Asia slipping back under the shadow of hunger and all the political and social disruptions that such misery causes. Few other things can promise as much.

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