At least 30,000 of the 350,000 known plant species on our planet are edible, according to the United Nations' Food and Agriculture Organization, but only 170 species of plant are cultivated for food on a large scale. As climate change affects plant yields and disease threatens some of our most popular crops (bananas, we’re looking at you), scientists say we need to explore so-called “forgotten foods” to diversify the crops we grow. But what are they — and what are some of the opportunities and challenges of growing them at scale?

BBC Climate and Science correspondent Georgina Rannard explains why food security is such an important issue - and the solutions scientists are finding to tackle this. Kew Gardens ethnobotanist Philippa Ryan, from the UK, tells us about some examples of forgotten foods. And BBC Africa business correspondent Jewel Kiriungi explains why seed sharing - a practice to help preserve crop diversity - is banned in Kenya.

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