International Journal of Horticulture, 2025, Vol.15, No.1, 41-50 http://hortherbpublisher.com/index.php/ijh 45 infections are increasingly adopted (Low et al., 2020). These varieties reduce the need for chemical pesticides, making cultivation more sustainable and cost-effective (Teshome et al., 2020). Breeding programs focus on improving resistance to fungal pathogens and optimizing post-harvest qualities, ensuring higher marketability and lower storage losses (Laurie et al., 2017). The introduction of pest-resistant cultivars not only enhances productivity but also promotes food security by minimizing losses from biotic stressors (Gibson and Aritua, 2022). 6 Case Study: High-Yield Fresh-Eating Sweet Potato Cultivation in Subtropical Regions 6.1 Overview of the selected study region’s climate and environmental conditions The selected study region for this case is a subtropical agricultural zone in East Africa, characterized by moderate rainfall, warm temperatures, and relatively high humidity during the growing season (Stathers et al., 2018). The annual rainfall in this region averages between 500 and 800 mm, which provides adequate moisture for sweet potato cultivation (Ndungu et al., 2016). However, the rainfall pattern is bimodal, with distinct dry and wet seasons, which creates challenges in water management (Cheboi et al., 2024). The average temperature ranges from 18 °C to 30 °C, with optimal growing conditions occurring during cooler months. Soils in this region are sandy loams with good drainage, essential for preventing root rot and promoting tuber formation (Motsa et al., 2015; Low et al., 2020; Wikifarmer, 2023). 6.2 Analysis of performance of the studied fresh-eating sweet potato varieties The study analyzed the performance of six high-yield fresh-eating sweet potato varieties. The field trial results showed that the trial locations were divided into two different climatic regions: warm temperate and cool subtropical. The Mvuvhelo variety performed particularly well at Ulundi 1 (47.4 t/ha) and Ekangala 2 (44.0 t/ha), while its total yield was very low at Ladysmith (8.1 t/ha), Nongoma 1 (10.5 t/ha), and Vryheid 1 (11.0 t/ha) (Figure 3). Ekangala 2 (37.9 t/ha), Ulundi 1 (36.5 t/ha), and Soshanguve (36.1 t/ha) showed the highest total yield, whereas Nongoma 2 (10.1 t/ha), Vryheid 1 (14.1 t/ha), and Winterveldt (17 t/ha) had lower average total yields (Figure 3). Among all varieties, timely sowing and regular irrigation in the early growth stage significantly increased yield and improved storage root quality. Additionally, crop performance was closely related to soil fertility management and pest control measures (Laurie et al., 2017; Zhapar et al., 2023). Figure 3 Locality by cultivar interaction means for total yield for six cultivars by 15 on-farm trials (localities) (Adopted from Laurie et al., 2017) 6.3 Insights from local farmers and their cultivation practices Interviews with local farmers revealed that successful cultivation depends heavily on the timing of planting to align with the rainy season and ensure sufficient soil moisture for vine establishment (Eitzinger et al., 2019). Farmers emphasized the importance of organic fertilizers and compost in maintaining soil health, especially given
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