by Larry Powell A vegetable garden in Manitoba. A PinP photo. American researchers believe they've found a way to genetically-engineer a dramatic increase in crop production. They've conducted field experiments with tobacco, using a new method which makes the critical process of photosynthesis much more efficient. (Tobacco was chosen because it's easy to modify and test. The same methods are now being tested on other crops including soybean, potato and tomato.) Photosynthesis allows plants to convert sunlight into energy and help them grow, increasing crop yield. To do this, most plants use the world's most plentiful enzyme, Rubisco, to capture carbon dioxide from the air and expel oxygen. But in a strange twist of nature, Rubisco captures more oxygen than it should. This produces a toxic compound in the plant which requires a lot of energy to get rid of. It could take more than a decade before this new technology can be put into widespread use