Performance of informal market sweet potato cultivars in on-farm trials in South Africa

Abstract

Several new sweet potato cultivars have been released in South Africa from 2004 until 2011 with varietal traits suitable for the informal market. This paper reports on results of on-farm trials conducted to evaluate the cultivars in broader agro-ecologies in the country. The trials were conducted at 15 localities across the 2011/12 to 2014/15 planting seasons including six cultivars with varying flesh colours. Data collection included marketable and unmarketable storage root yield classes, dry mass, and taste acceptability. The sites were representative of cool subtropical and warm temperate regions. Statistical analysis included ANOVA, AMMI, Discriminant analysis (DA) and Principal component analysis (PCA). Significant effects were detected for locality*cultivar and region*cultivar interactions for total and marketable yield, and for cultivar only for marketable yield. The factor region was not significant. The mean marketable yield ranged from 13.1 to 19.0 t/ha, being highest for 199062.1 and Ndou, while Bophelo had average stable yield over a broad range of environments. The most prevalent unmarketable class was weevil damage (15.1%). The study demonstrated PCA and DA as quick analytical tools to associate quality traits with cultivars to facilitate cultivar recommendations. Bophelo and Ndou had been sold with success on local informal markets and have large potential to be promoted wider.

Improving the Dietary Vitamin A Content of Rural Communities in South Africa by Replacing Non-Biofortified White Maize and Sweet Potato with Biofortified Maize and Sweet Potato in Traditional Dishes

“…They were among the progeny of the first set of crosses conducted among elite parental lines imported from CIP, Peru. This first series of crosses were referred to as the “A” series, and proved the most successful with seven crosses being released and grown by small and large-scale farmers [25,26].…”

Orange-Fleshed Sweet Potato

“…22,41 Multiple studies have shown that African consumers typically prefer sweet potatoes with high dry matter and low water content. 42 –44 A choice experiment conducted in 2008 in 2 provinces of Mozambique revealed that willingness to pay for high dry matter content (associated with a firm, starchy potato) was almost twice that of willingness to pay for the color of pulp, even when consumers received information about the health benefits of consuming OFSP. 22,41 The Resisto variety has been shown to be popular in Mozambique due to its taste, dark-orange color, growth structure, and high yields but was found to be less drought-tolerant than the light-orange Jonathan variety.…”

Nutrient-Dense Orange-Fleshed Sweetpotato: Advances in Drought-Tolerance Breeding and Understanding of Management Practices for Sustainable Next-Generation Cropping Systems in Sub-Saharan Africa

“…van Vugt and Franke (2018) defined attainable yield as the mean onfarm yield plus three times the standard deviation and found that attainable root yields varied from 18 to 32 t ha −1 among districts in Malawi. Attainable root yields in experimental farms under rainfed conditions were 25 t ha −1 in Cameroon (Yengoh and Ardo, 2014), 25-29 t ha −1 in South Africa (Laurie et al, 2017), 27 t ha −1 in Mozambique (Andrade et al, 2017b), 27-32 t ha −1 in Rwanda (Rukundo, 2015) and 39 t ha −1 in Nigeria (Uwah et al, 2013). Despite the reputation of sweetpotato as a robust crop tolerant to low inputs and minimal crop management, based on these numbers it appears that a 100-200% yield increase can realistically be obtained with improved crop management (Oswald et al, 2009).…”

“…There has been meager research regarding the critical understanding of the water requirement and use efficiency of sweetpotato (Gomes and Carr, 2003;Gomes et al, 2005;Laurie et al, 2017). An important proxy for the water requirements of a crop is the crop coefficient (Kc), which relates crop water requirement to the reference evapotranspiration figure of a given area 7 .…”

“…Ntsieni (2017) quantified ETc dynamics under a range of growing conditions and determined average crop coefficient (K c ) values to be 0.46, 0.92, and 0.57 during initial, middle, and late growing stages. Growing OFSP using an infield water harvesting system showed significantly higher yields than that with conventional tillage; thus enabling farmers in semi-arid areas to grow small plots of OFSP and add vitamin A to their diets (Laurie et al, 2017). Yooyongwech et al (2016) reported that inoculation of arbuscular mycorrhizal fungi 8 in sweetpotato plants improves plant growth characteristics and enhances tolerance to water deficit via soluble sugars and free proline accumulation.…”