Effect of cultivar and cutting orientation at planting on sweet potato growth and yield in the Verulam area, South Africa

Abstract

Sweet potato production is affected by agronomical practices such as orientation of cuttings at planting and cultivar selection. Thus a study was conducted to test the effect of two cutting orientations at planting (horizontal and vertical) for four sweet potato cultivars (‘Ndou’, ‘Blesbok’, ‘Monate’ and ‘199062.1’) on vine length and yield in the Verulam area of northern KwaZulu-Natal, South Africa. The experiment was laid out in a randomised complete block design with four replications per treatment. Vine length was measured for five randomly selected plants per plot at 3, 6, 9 and 12 weeks after planting. At 5 months after planting, aboveground fresh biomass (ABM), marketable yield (MY) (101–1 200 g), non-marketable yield (<100 g), total storage root yield (TSRY) and harvest index (HI) were determined. Vine length was not significantly affected by cultivar or cutting orientation, but was shortest for cultivars ‘199062.1’ and ‘Blesbok’. Cultivars ‘199062.1’ and ‘Blesbok’ had the highest ABM, MY and TSRY. Horizontal planting of cuttings showed consistently higher values than vertical planting for most yield parameters measured with significant (p < 0.05) differences in TSRY and HI observed.