Improving rapid multiplication of sweetpotato (Ipomoea batatas L. (Lam) pre-basic seed using sandponics technology in East Africa

Abstract

Sweetpotato (Ipomoea batatas, Convolvulaceae) is an important food crop in Sub-Saharan Africa (SSA). Lack of access to quality sweetpotato planting material after sweetpotato limits utilization of market oriented improved clones and new varieties. Obtaining clean planting material in the right quantity and quality is a challenge in the SSA region. Farmers often obtain planting materials from their own sources with multiple rooting, drawn from a previous crop or neighbors and face the risk of it being infected with sweetpotato viruses. The objective of this study was to examine the economic and physical yield performance of sandponics multiplication method by comparing with conventional soil method using optimal N-nutrient inputs. The performance of five sweetpotato cultivars (Irene, Delvia, Tanzania, Gweri, and Kabode) in the modified prototype sweetpotato nutrient media was evaluated. Vine production utilizing modified sandponics nutrient media with trellised plants was compared to the conventionally used soil media. Analysis of variance indicated that the main effects of cultivar and substrate were highly significant (p < 0.0001) for nodes produced, vine multiplication rate (VMR), number of cuttings produced, and vine length. In addition, cultivar by substrate interaction was highly significant at 0.01 probability level for nodes produced, VMR, and vine length. Vine multiplication rate was 33% higher in the sandponics system compared to the conventional soil method of multiplying sweetpotato vines. Among the cultivars studied, Irene was the most favorable cultivar with a VMR of 65.2 in sand and 45.5 in soil. The cost-effectiveness analysis indicates that the cost per cutting (i.e., 3–4 nodes) produced from sandponics method was 4.6 KSH (US$ 0.046) as compared to 3.1 KSH (US$ 0.031) per cutting produced from conventional method. Sandponics system is competitive due to its capability of increased VMRs. However, the optimal number of ratooning needs to be investigated to understand the economies of scale in future research.

Loop‐mediated isothermal amplification assay: A novel disease diagnostics tool in sweetpotato seed quality assurance

“…The lack of obvious symptoms from sweetpotato viruses in single infections makes it difficult to select virus‐free planting materials (Gibson & Kreuze, 2015). Sweepoviruses and related viruses belonging to the family Geminiviridae , genus Begomovirus , are increasingly recognized as commonly infecting sweetpotato and can cause significant yield losses despite the lack of obvious foliar symptoms (Wanjala et al., 2020; Zhang & Ling, 2011). Begomoviruses are considered the most destructive viruses in tropical and subtropical agricultural areas.…”

Development of control strategies for bacteria and fungi associated with a micropropagated new cultivar of orange-fleshed sweet potato (Ipomoea batatas cv. Agrosavia–Aurora)

“…The plant material typically used for sweet potato propagation is represented by cuttings obtained from previous commercial crops, multiplied mainly by vegetative propagule propagation (Kim et al 2015;Qiao et al 2019;Ssamula et al 2020), exchanged from farmer to farmer and from one cycle to another, with multiple rooting and without renewal (Rajendran et al 2017). This vegetative propagation without proper management has resulted in the accumulation of diseases from generation to generation (Kim et al 2017;Wanjala et al 2020). This low phytosanitary quality is mainly due to bacteria, fungi, and viruses that affect both production and quality of tuberous roots (Mwanga et al 2017;Makokha et al 2020;Abrham et al 2021).…”

“…This low phytosanitary quality is mainly due to bacteria, fungi, and viruses that affect both production and quality of tuberous roots (Mwanga et al 2017;Makokha et al 2020;Abrham et al 2021). Thus, the use of high-quality planting material is one of the keys to increase sweet potato productivity (Wanjala et al 2020;Abrham et al 2021).…”

“…Phytopathogenic fungi, especially species of the genera Fusarium, Alternaria, Sphaceloma, and Sclerotium (Aguoru and Amuzie 2009;Ekman and Lovatt 2015;Paul et al 2017;Samiyarsih et al 2018), as well as bacteria of the genera Streptomyces, Pseudomonas and Ralstonia (Jena and Samal 2011;Ekman and Lovatt 2015;Mwanga et al 2017;Zhang et al 2018), are among the major constraints for sustainability of sweet potato production and tuber quality (Mwanga et al 2017;Makokha et al 2020). Virus diseases, spread through infected propagation material, also represent an important phytosanitary problem in sweet potato (Wanjala et al 2020;Jo et al 2020): Sweet potato chlorotic stunt virus (genus Crinivirus, family Closteroviridae), Sweet potato feathery mottle virus (genus Potyvirus, family Potyviridae) and Sweet potato leaf curl virus (genus Begomovirus, family Geminiviridae) are some major viral pathogens of sweet potato responsible for substantial damage to the world's sweet potato industry (Kim et al 2017;Mwanga et al 2017;Mulabisana et al 2018;Zhang et al 2020).…”

Response of Sweet Potato to Substrates and Acclimatization Conditions in the Greenhouse to Produce High-quality Planting Material

“…The main strategy to avoid water loss and maintain adequate relative humidity involves the use of substrates with good moisture retention and the incorporation of humid chambers, respectively (Chandra et al, 2010;Gonçalves et al, 2017). In sweet potato, acclimatization methods have been reported in a mesh house with sandponic substrates (Wanjala et al, 2020), and a mixture of soil, compost and sand (1:1:2) (Beyene et al, 2020) and good results were obtained for seedling development considering the particular conditions in each case. However, determining the best acclimatization conditions for in vitro sweet potato plants is essential to the successful high-quality planting material production process; therefore, the objective of this research was to improve the conventional production system for planting material of sweet potato (I. batatas L.) by recognizing its response to several substrates and acclimatization conditions under greenhouse conditions.…”