TUMBY BAY - According to the UN’s Food and Agriculture Organisation, the sweet potato is the world’s seventh most important crop in terms of the weight of food produced.
Sweet potato was first domesticated in the Americas more than 5,000 years ago but didn’t reach Papua New Guinea until about 500 years ago.
When it did it created major shifts in settlement patterns and accelerated population growth.
Sweet potatoes aren't tubers, like potatoes. They are swollen and puffed-up parts of a plant’s root. As of 2013, there were approximately 7,000 sweet potato cultivars.
People grow sweet potato in many parts of the world, including New Zealand, Australia, the Philippines, Japan, Hawaii, China, North America and, of course, in Papua New Guinea and the Pacific Islands.
In PNG, more than 1,000 varieties are grown by small-scale farmers and gardeners, who propagate the plant using cuttings rather than seeds which are used for commercial crops.
The reason for the many varieties is that each was developed through selection and breeding by different gardeners in relative isolation. Just as one group may have spoken a different language to the people in the next valley, it is likely they also grew a different variety of kaukau.
Americans especially, but other people too, like their sweet potatoes orange, mushy and packed with sugar. Of all the different sweet potatoes in the world this is the one that is most extensively grown as a commercial crop.
Two sweet potato varieties recently developed in the USA have been patented – the first patents given to sweet potatoes.
One of the varieties is resistant to parasitic nematodes and the other is good for processing and makes good baby food puree. It’s also attractive not only as a crop product but for canning.
This variety is called ‘Covington’ and was developed and patented in 2008. It is now grown extensively as a newer variety of sweet potato for commercial food production.
What tends to happen with patented crop varieties is that they eventually push out traditional varieties and become the dominant crop grown. Those traditional varieties then die out through lack of cultivation and usage.
In the USA hybrid crops like corn are dominated by patented varieties sold by big agricultural companies. The companies require buyers to sign agreements that create strict limits on how the seeds can be used.
Farmers are generally prohibited from saving seed from their crops to plant the following year. New seeds must be purchased for each planting.
The same thing is beginning to happen with the sweet potato.
So what does this mean for Papua New Guinea?
Well, it might surprise you to learn that the original 1,000 odd varieties of kaukau are rapidly diminishing in number. Many growers now seems to be cultivating the same few varieties.
It might also surprise you to know that hybrid varieties of kaukau have already been introduced into PNG and are being promoted by the government.
This is not to suggest there is any intention at restricting what sort of kaukau is grown. At present the intention is to produce varieties that are resistant to disease and particularly resistant to frost, such as that which occurred in the recent drought in the highlands.
The developments do suggest, however, that this trend could lead to hardy monoculture varieties replacing many of the current traditional varieties.
The inherent danger in this is that the development of a hardier variety may attract the attention of one or more of the big multinational agricultural companies.
If you add to that a couple of opportunistic politicians who can see kickbacks on the horizon, a real possibility of losing traditional varieties exists.
Nothing is sacred in the world of business and a simple thing like destroying a subsistence agricultural tradition hundreds of years old would be of little consequence as long as it realised a profit.
It is hard to imagine Papua New Guineans being stuck with horrible mushy orange kaukau but, then again, who would have predicted many people’s current reliance on rice.