In our second and final episode on the humble spud, we meet the people who see the global economic future as being potato powered. The potato is the world's most produced staple food after rice, wheat and corn - yet historically, it was seen as the root of filth, misery and obesity. In our previous episode we heard how over time it came to be used as a tool of power by the state, to create a healthy and robust workforce. This week, food historian Rebecca Earle, tells us that history is repeating itself in China, which is now the world's biggest producer of potatoes. China's central government sees the potato as key to food security, but it's got some work to do to produce a cultural shift away from rice. We'll be serenaded by one of the country's potato champions, the operatic 'new farmer' Sister Potato, who says she is changing hearts, minds and cuisine with her songs. Then we'll head to the streets of Beijing to gauge enthusiasm and ask can the spud shake off its lowly reputation? Africa and developing countries have the biggest predicted growth in potato production in the coming decades. But is the world in danger of putting all its spuds in one basket? We’re asking whether the potato is the answer to food security or if the vegetable’s patchy history doomed to repeat itself. Plus we head to Peru to visit the scientists protecting thousands of varieties of potato, and meet the man who ate nothing but potatoes - for a year. (Image: A farmer eats a potato in China . Credit: Spencer Platt/ Getty Images)