African Journal of Agriculture

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 202–206

DOI: 10.46882/2026/AJA/000759

Article Type: Full Length Research Paper

Title: An Optimized Protocol for High-Yield Total RNA Extraction from Soursop (Annona muricata L.) Fruit Tissues

Names of Authors: Isabella Montenegro Brasil¹*, Maria de Lourdes Oliveira Otoch², José Hélio Costa³, Geraldo Arraes Maia¹, Maria da Guia Silva Lima⁴, Birgit Arnholdt-Schmitt⁵, Dirce Fernandes de Melo⁴

Authors’ Affiliations: ¹Fruit and Vegetable Laboratory/Food Technology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil; ²Biology Department/University of Ceará State, Fortaleza, Ceará, Brazil; ³Biochemistry and Molecular Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil; ⁴Bioenergetics Laboratory/Biochemistry and Molecular Biology Department, Federal University of Ceará, Fortaleza, Ceará, Brazil; ⁵Biocenter Klein Flottbek, Institute of Botany (AMP II), University of Hamburg, Germany

Abstract: Soursop fruit tissue is known by its acidic pH and high levels of polysaccharides, polyphenolics and secondary metabolites. These conditions are recognized to interfere unfavorably with conventional methodologies for RNA isolation. We describe here a rapid and simple method for the isolation of total RNA from soursop fruit. RNA was extracted in less than 4 h through a combination of SDS/potassium acetate precipitation and selective binding on a silica-gel-based membrane (Qiagen) through microspin speed technology. In comparison to other methods applied for RNA extraction from soursop fruit, our protocol improved substantially RNA quality as well as RNA yield. The isolated RNA served as a robust template for RT-PCR analysis. Comparable RNA quality and yield per dry weight were obtained from unripe and ripe fruits. This makes the method appropriate to being used in studies on differential gene expression in post-harvest behavior.

Key words: Annona muricata L., RNA isolation, tropical fruit.

Manuscript Timeline: Received: July 05, 2026; Revised: August 10, 2026; Accepted: August 22, 2026; Published: August 31, 2026

Citation: Brasil, I. M., Otoch, M. L. O., Costa, J. H., Maia, G. A., Lima, M. G. S., Arnholdt-Schmitt, B., & de Melo, D. F. (2026). An Optimized Protocol for High-Yield Total RNA Extraction from Soursop (Annona muricata L.) Fruit Tissues. African Journal of Agriculture, 13(8), 202–206. DOI: 10.46882/2026/AJA/000759

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 194–201

DOI: 10.46882/2026/AJA/000758

Article Type: Original Research Article

Title: Genotype-by-Environment Interaction and Yield Stability of Orange-Fleshed Sweet Potato (Ipomoea batatas L.) in Different Agro-Ecologies of Mozambique

Names of Authors: Mateus A. Macamo¹, Elena S. Mondlane¹, Joao B. Nhantumbo²

Authors’ Affiliations: ¹Instituto de Investigação Agrária de Moçambique (IIAM), Maputo, Mozambique; ²Faculdade de Agronomia, Universidade Eduardo Mondlane, Maputo, Mozambique

Abstract: Orange-fleshed sweet potato (OFSP) genotypes are widely disseminated in Mozambique to alleviate widespread vitamin A deficiency and combat rural child malnutrition. However, significant genotype-by-environment interactions (GEI) can complicate breeding selections and destabilize root yields across diverse agro-ecological zones. This study evaluated the yield stability and environmental adaptability of ten advanced OFSP genotypes across four distinct agro-ecological test stations (Gaza, Inhambane, Manica, and Zambézia) over two consecutive growing seasons. The field experiments were conducted using a randomized complete block design with three replications per site. Main root yield data were subjected to additive main effects and multiplicative interaction (AMEMI) analysis and genotype main effect plus genotype-by-environment interaction (GGE) biplot analysis. The AMEMI analysis revealed that environment, genotype, and GEI explained 58.4%, 18.2%, and 23.4% of the total storage root yield variation respectively (p < 0.01). The GGE biplot identified the genotype 'Delvia' as the most stable and high-yielding line, achieving a grand mean storage root yield of 18.62 ± 1.15 t/ha across all four locations. Conversely, genotype 'Irene' was highly adapted to the high-rainfall zone of Zambézia but performed poorly in the drought-prone sands of Gaza. 'Delvia' also maintained an acceptable total carotenoid level (74.2 μg/g fresh weight basis), making it the premier choice for nationwide food security scaling.

Keywords: GGE biplot, Additive main effects, Root stability, Ipomoea batatas, Beta-carotene, Multi-locational trials

Manuscript Timeline: Received: July 02, 2026; Revised: August 05, 2026; Accepted: August 20, 2026; Published: August 31, 2026

Citation: Macamo, M. A., Mondlane, E. S., & Nhantumbo, J. B. (2026). Genotype-by-Environment Interaction and Yield Stability of Orange-Fleshed Sweet Potato (Ipomoea batatas L.) in Different Agro-Ecologies of Mozambique. African Journal of Agriculture, 13(8), 194–201. DOI: 10.46882/2026/AJA/000758

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 186–193

DOI: 10.46882/2026/AJA/000757

Article Type: Original Research Article

Title: Socio-Economic Evaluation of Youth Participation in High-Value Horticultural Value Chains in Southern Rwanda

Names of Authors: Jean de Dieu Niyomugabo¹, Marie Claire Uwiringiyimana¹

Authors’ Affiliations: ¹Department of Agricultural Economics and Rural Development, University of Rwanda, Nyagatare, Rwanda

Abstract: Rural youth unemployment remains a major structural challenge across East Africa, yet high-value vegetable and fruit value chains offer lucrative pathways for rural employment and wealth creation. This study investigated the socio-economic determinants and financial outcomes of rural youth participation in commercial tomato and sweet pepper value chains in southern Rwanda. A multi-stage random sampling approach was used to interview 320 youth farmers (aged 18–35 years) across four administrative districts. Double-hurdle econometric modeling was deployed to isolate the factors driving the choice to enter horticulture from the factors dictating the scale of commercial market participation. The empirical findings showed that 38.4% of the sampled youth were actively engaged in commercial horticulture. The first-stage probit results indicated that access to specialized vocational training, ownership of land, proximity to paved transit corridors, and participation in youth savings groups significantly increased the probability of entering high-value markets (p < 0.01). The second-stage regression revealed that the volume of produce sold was heavily constrained by lack of access to cold-storage facilities and formal contract agreements. Financial margin analysis revealed that youth growers engaged in micro-irrigation earned a mean net income of US$ 1,450 per season, which was 64.0% higher than the local average wage. The study concludes that rural youth development programs should prioritize investments in localized irrigation assets and market connection contracts.

Keywords: Double-hurdle model, Youth employment, Horticulture value chains, Market participation, Vegetable farming, Income transformation

Manuscript Timeline: Received: June 28, 2026; Revised: August 02, 2026; Accepted: August 18, 2026; Published: August 31, 2026

Citation: Niyomugabo, J. D., & Uwiringiyimana, M. C. (2026). Socio-Economic Evaluation of Youth Participation in High-Value Horticultural Value Chains in Southern Rwanda. African Journal of Agriculture, 13(8), 186–193. DOI: 10.46882/2026/AJA/000757

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 178–185

DOI: 10.46882/2026/AJA/000756

Article Type: Original Research Article

Title: Impact of Silicon Soil Amendments on Resistance to African Rice Gall Midge (Orseolia oryzivora) in Lowland Rice Varieties

Names of Authors: Chukwudi N. Eze¹, Blessing I. Udoh¹, Amara C. Nwosu²

Authors’ Affiliations: ¹National Cereals Research Institute (NCRI), Badeggi, Nigeria; ²Department of Crop Science, University of Nigeria, Nsukka, Nigeria

Abstract: The African rice gall midge (Orseolia oryzivora Harris) is a destructive insect pest that induces severe vegetative distortion and sterile galls ("onion shoots") in lowland rice ecosystems across West Africa. Silicon (Si) accumulation in grass tissues is known to enhance mechanical defense against chewing and sucking pests, but its efficacy under heavy gall midge pressure requires field verification. This 2-year field study evaluated the effect of four calcium silicate soil amendment rates (0, 50, 100, and 150 kg Si/ha) on the resistance and yield of three lowland rice varieties (FARO 44, FARO 52, and a susceptible local check). The field design utilized a split-plot layout with four replications. The results demonstrated that applying 150 kg Si/ha significantly reduced the percentage of onion shoots from 24.6% to 6.2% across all varieties (p < 0.01). Scanning electron microscopy confirmed a dense deposition of silica bodies in the epidermal cells of leaf sheaths, which mechanically disrupted larval boring activity. The silicon-amended plots maintained significantly higher productive tiller counts and leaf area indices. Variety FARO 52 treated with 100 kg Si/ha produced the highest grain yield (5.24 ± 0.28 t/ha), representing a 38.5% yield increase over the unamended control. This research highlights silicon application as a highly viable, eco-friendly component of integrated pest management for sustainable rice production.

Keywords: Orseolia oryzivora, Calcium silicate, Mechanical defense, Lowland rice, Onion shoots, Grain yield

Manuscript Timeline: Received: June 25, 2026; Revised: July 28, 2026; Accepted: August 16, 2026; Published: August 31, 2026

Citation: Eze, C. N., Udoh, I. I., & Nwosu, A. C. (2026). Impact of Silicon Soil Amendments on Resistance to African Rice Gall Midge (Orseolia oryzivora) in Lowland Rice Varieties. African Journal of Agriculture, 13(8), 178–185. DOI: 10.46882/2026/AJA/000756

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 170–177

DOI: 10.46882/2026/AJA/000755

Article Type: Original Research Article

Title: Socio-Economic Impacts of Micro-Credit Access on Agro-Input Adoption among Female Wetland Rice Farmers in Southern Sierra Leone

Names of Authors: Sahr M. Fofanah¹, Fatmata B. Kamara¹, Zainab H. Kanu²

Authors’ Affiliations: ¹Sierra Leone Agricultural Research Institute (SLARI), Freetown, Sierra Leone; ²Department of Agricultural Economics and Extension, Njala University, Njala, Sierra Leone

Abstract: Women provide a large share of the labor for wetland rice (Oryza sativa L.) farming in southern Sierra Leone, yet structural gender gaps in credit access limit their ability to purchase certified seeds and mineral fertilizers. This study evaluated the socio-economic impacts of formal micro-credit access on agro-input spending and net farm returns among 360 female wetland rice growers. Data were gathered through a structured rural survey across three districts. Propensity Score Matching (PSM) was used to control for self-selection bias and compare credit recipients with non-recipients. The empirical models revealed that cooperative membership, land holding size, and distance to the nearest financial hub significantly influenced micro-credit access (p < 0.05). PSM estimates showed that women with access to micro-credit spent an average of 42.5% more on certified, high-yielding rice seeds (such as ROK 5) and applied 35.0 kg/ha more urea fertilizer than non-recipients. This input expansion translated into a significant average yield gain of 1.15 t/ha, lifting net household seasonal crop income by US$ 324. The study concludes that expanding tailored micro-finance options for women agricultural cooperatives is a highly effective way to increase input adoption and secure rural food security.

Keywords: Propensity score matching, Micro-credit, Gender dynamics, Wetland rice, Input adoption, Economic empowerment

Manuscript Timeline: Received: June 22, 2026; Revised: July 24, 2026; Accepted: August 14, 2026; Published: August 31, 2026

Citation: Fofanah, S. M., Kamara, F. B., & Kanu, Z. H. (2026). Socio-Economic Impacts of Micro-Credit Access on Agro-Input Adoption among Female Wetland Rice Farmers in Southern Sierra Leone. African Journal of Agriculture, 13(8), 170–177. DOI: 10.46882/2026/AJA/000755

African Journal of Agriculture | Vol. 13, No. 8, August 2026 | pp. 162–169

DOI: 10.46882/2026/AJA/000754

Article Type: Original Research Article

Title: Nutritional Profile and In Sacco Dry Matter Degradability of Spineless Cactus Pear (Opuntia ficus-indica) Varieties in Arid Karoo, South Africa

Names of Authors: Willem J. Viljoen¹, Hendrik P. Pretorius¹

Authors’ Affiliations: ¹Department of Animal, Wildlife and Grassland Sciences, University of the Free State, Bloemfontein, South Africa

Abstract: Severe recurrent droughts in South Africa’s arid Karoo region routinely lead to rangeland depletion and livestock starvation. Spineless cactus pear (Opuntia ficus-indica) varieties offer an emergency forage and water source for ruminants during dry seasons, but their precise nutritional profiles require systematic characterization. This study evaluated the proximate chemical composition, mineral profile, and in sacco dry matter degradability (DMD) of four spineless cactus pear cultivars (Morado, Fresno, Skinner, and Algerian). Rumen-cannulated Merino wethers (n = 4; body weight 46.5 ± 1.2 kg) were utilized to determine in sacco degradability kinetics at 6, 12, 24, 48, and 72 hours. Proximate analysis revealed high moisture (88.4% to 91.2%) and ash (16.2% to 18.5% DM base) contents across all cultivars. Crude protein content was low, ranging from 4.82% in Skinner to 6.24% in Algerian. Cultivar Algerian recorded the highest soluble carbohydrate fraction and the lowest neutral detergent fiber (NDF) value (32.4%). In sacco DMD analysis demonstrated that Algerian achieved the highest effective degradability (78.4% at a passage rate of 0.05/hour). The potential degradable fraction correlated negatively with NDF accumulation. This study establishes that while Opuntia ficus-indica is a valuable energy and water supplement, it must be paired with a protein concentrate to balance ruminant maintenance diets.

Keywords: Opuntia ficus-indica, In sacco degradability, Arid zones, Ruminant nutrition, Chemical composition, Forage security

Manuscript Timeline: Received: June 18, 2026; Revised: July 20, 2026; Accepted: August 11, 2026; Published: August 31, 2026

Citation: Viljoen, W. J., & Pretorius, H. P. (2026). Nutritional Profile and In Sacco Dry Matter Degradability of Spineless Cactus Pear (Opuntia ficus-indica) Varieties in Arid Karoo, South Africa. African Journal of Agriculture, 13(8), 162–169. DOI: 10.46882/2026/AJA/000754