There are over 400,000 species of plant on earth, they’re on every continent including Antarctica. But humans only regularly eat about 200 species globally, with the vast majority of our nutrition coming from just three species. Many of the fruits, leaves and tubers that other plants grow are packed full of toxins that are poisonous to us, and would make us very ill if we ate them. But could we take out the poisons and create new, edible crops? That’s what CrowdScience listener Marija wants to know.

Crowdscience dives into this topic, and uncovers the that many crops are poisonous, and why so few plants are eaten globally. Host Anand Jagatia finds that even the modern scientific processes of crop breeding are very slow. But science can now engineer plants at the genetic level by adding, silencing or removing specific genes. This ‘genetic modification’ is hugely controversial but can be highly effective.

Anand finds a man who has spent decades making cotton seeds edible by removing the poisons they naturally produce in their seeds. This GM crop could help fend-off starvation. But sometimes introducing poisons can be as important as removing them, as we find in the genetically modified ‘BT eggplants’ in Bangladesh. The new gene makes the vegetable toxic to a major insect pest, so they are much easier to grow.

But GM crops are not the perfect solution. They have problems of gene escape, can increase the use of environmentally damaging herbicide, and can be open to monopolisation. In some countries, particularly in Europe, GM crops are hugely controversial. Anand finds out whether these concerns stand up to science and looks at the counterpoint in developing countries in Africa, South Asia and elsewhere, where local farmers like Patience Koku in Nigeria have little time for some of the concerns around GM, particularly as they see poor harvests, poverty and starvation as the more pressing problems.

Contributors: Professor Sandra Knapp, The Natural History Museum in London Professor Julie King, Nottingham University Professor Keerti Rathore, Texas A&M University Dr Yousuf Akhond, Bangladesh Agricultural Research Institute Professor Matthew Cobb, University of Manchester Patience Koku, Nigerian Farmer and member of the Global Farmer’s Network Alliance for Science

Produced by Rory Galloway and presented by Anand Jagatia for the BBC World Service.

Image: Farmer with Fruits. Credit: Arif Hossain, Farming Future Bangladesh.

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