Esmeraldo Maligsa, a farmer and president of the Bohol Ube Growers Association, harvests 2,000kg (4,400lbs) of ube, the purple tuber native to the Philippines, every seven months. He and the other farmers in his group manage a collective yield of between 5 tonnes and 8 tonnes, fetching prices of 90 to 100 pesos (US$1.50 to US$1.70) per kg. Such is the price the ubi kinampay, dubbed the “Queen of Philippine yams”, fetches. It is grown in Bohol province and nearby areas in central Philippines, and...