Luis Herrera-Estrelia, a botanist at the Centre for Research and Advanced Studies in lrapuato, Mexico, has inserted a gene for citric acid production into tobacco plants and studied how they grow in alkaline soils. When lightly fertilised, the plants grew 20 per cent more than tobacco plants without the new gene. The plants also achieved maximum growth using half the fertiliser required by normal plants. Herrera-Estrelia and his team have also inserted the gene into rice and maize. Preliminary tests suggest that it is even more effective in these crops, he says, though he will not have complete results of large-scale greenhouse experiments for another 18 months.
Commercial development is likely to take three more years after that.
If trials are successful, cash-strapped farmers in developing countries could reap the benefits of fertillser for a fraction of the cost. Insoluble phosphates would also be less likely to contaminate the water table. Herrera-Estrelia's team has filed for patents on the genetically modified plants but say they will only enforce them against people who can easily afford to pay. Nigerian traditional' healers use seeds of the Garcinia kola tree, known as bitter kola, as a remedy for many ailments. Unlike most other candidates, it doesn't appear to be toxic.