Tracing the Journey of Kaukau

In Papua New Guinea (PNG), sweet potato, locally known as kaukau, is one of the most important root crops in the country. It contributes around 60% of the total food energy derived from staple food crops, making it central to food security and daily life for millions of Papua New Guineans. According to a value chain analysis of sweet potato in PNG by Hui-Shung Christie Chang and John Kewa, the crop is grown throughout the country, with approximately 75% of production concentrated in the Highlands region.

But where did sweet potato originally come from, and how did it find its way to Papua New Guinea?

Research shows that the sweet potato originated in north-western South America, where it was domesticated around 2500 BC, alongside the development of early tropical forest agricultural societies. From there, its journey across the world began. The Spanish introduced sweet potato to Europe, after which it spread to regions including China, Japan, Malaysia, and the Moluccas in eastern Indonesia. The Portuguese later carried it to India and Africa.

Long before European contact in the Pacific, the sweet potato had already reached Polynesia, particularly Samoa. From there, it is believed to have spread across the Pacific through early Polynesian voyaging and trade networks, eventually reaching Papua New Guinea. The local name kaukau reflects this shared Pacific history, closely resembling the names used in other Pacific cultures, such as kumala, kumara, and kālua.

Today, sweet potato remains a cornerstone of PNG’s food system. Beyond being a staple crop, it has become an important cash crop for smallholder farmers, providing income that helps sustain families and rural livelihoods.

The story of the sweet potato is one that stretches across oceans, continents, and centuries, from its origins in South America to its deep cultural and economic roots in Papua New Guinea.

Before learning these facts, where did you think the sweet potato originally came from?