Sweet potato in Papua New Guinea: how farmers' perceptions of quality meet with open market demand in Port Moresby

This research is part of an Australian Centre for International Agricultural Research-funded project in Papua New Guinea to improve the supply chain for Ipomoea batatus (sweet potato, known locally as kaukau). Determining quality standards is considered essential for smallholder farmers to contemplate developing new high-quality markets for their produce. Following postharvest training, farmers could discriminate between different qualities of kaukau. Gradings were based largely on root size, but also on appearance. In Port Moresby open markets, kaukau were sold in heaps that were based mainly on size. But we discovered the kaukau in larger heaps were also sold at a higher price per kg despite the absence of weighing scales. More uniform-sized kaukau heaps are now increasingly being seen in the Port Moresby open markets. From this research, two grades are proposed: one of a higher quality based on size (length 15-25 cm and largest width or diameter >4 cm) and appearance (no harvest cuts and no rodent or insect damage), and the second grade being any other kaukau. This is a first attempt to help farmers focus attention on a quality standard and seek out markets for that quality of produce.