A comparison of Maori and commercial sweetpotato (Ipomoea batatas) crop establishment methods in New Zealand

Kūmara (sweetpotato, Ipomoea batatas (L.)), introduced by Māori to New Zealand as early as 600-700 ybp, is cultivated exclusively by vegetative means in all systems in the country’s temperate climate. Tipu (root sprouts) are raised from storage roots and planted directly into the ground for cultivation. Traditional Māori methods pull the tipu from the parent root while modern commercial methods rely on tipu cut from the parent kūmara and planted directly. An experiment using the cultivar Owairaka Red was undertaken to determine the differences between methods in plant establishment 30 days after transplanting. Tipu with pre-rooting were found to have a significantly higher leaf area, fresh and dry root and shoot weights, and lower shoot to root ratios (p < 0.001). Furthermore, it can be postulated that traditionally cultivated tipu produce plants with greater drought resistance as well as a competitive ability against weeds in the critical stages of early establishment. In consideration of climate change, plants adaptive to marginal regions and resilient to diverse conditions are likely to be an important long term benefit to traditional Māori agricultural systems.