In recent years, more agricultural lands are been converted to photovoltaic (PV) power plants for better return on investment. However, prioritizing energy generation over food production poses a significant threat to the well-being of the rapidly growing global population. Agro-photovoltaics (APV) provide an opportunity to integrate crop production under PV panels. The objective of this study was to investigate the effect of APV system on microclimate, photosynthesis, and agronomic performance of mungbean in a tropical environment. Five mungbean genotypes, Tvr18, Tvr28, Tvr65, Tvr79 and Tvr83 were assessed under three APV micro environments, East-west facing PV (WPV), West-east facing PV (EPV), and no PV (NPV) in a split plot design with 5 replications. Results obtained showed significant reduction (p < 0.05) in photosynthetic active radiation (5–47%), leaf temperature (3–9%), and in the proportion of potentially harmful unregulated energy reaching the reaction centers (19–23%) under the PV (% reduction in WPV > EPV). Relative humidity, photochemical energy conversion, plant height, number of leaves, pods, and seeds were increased significantly (p < 0.05) underneath the EPV compared to NPV. Seed weight also increased non-significantly under EPV while flowering and podding behaviour, leaf area and stem diameter were comparable (p > 0.05) in NPV and EPV. We report for the first time that microclimate, growth, photochemistry and yield performances of mungbean were improved under APV system in a tropical environment. The improved performances of mungbean under EPV compared to WPV suggest that PV orientation is important and should not be overlooked in APV system designs.

The galloping rise in global population in recent years and the accompanying increase in food and energy demands has created land use crisis between food and energy production, and eventual loss of agricultural lands to the more lucrative photovoltaics (PV) energy production. This experiment was carried out to investigate the effect of organic photovoltaics (OPV) and red-foil (RF) transmittance on growth, yield, photosynthesis and SPAD value of spinach under greenhouse and field conditions. Three OPV levels (P0: control; P1: transmittance peak of 0.11 in blue light (BL) and 0.64 in red light (RL); P2: transmittance peak of 0.09 in BL and 0.11 in RL) and two spinach genotypes (bufflehead, eland) were combined in a 3 × 2 factorial arrangement in a completely randomized design with 4 replications in the greenhouse, while two RF levels (RF0: control; RF1: transmittance peak of 0.01 in BL and 0.89 in RL) and two spinach genotypes were combined in a 2 × 2 factorial in randomized complete block design with four replications in the field. Data were collected on growth, yield, photosynthesis and chlorophyll content. Analysis of variance (ANOVA) showed significant reduction in shoot weight and total biomass of spinach grown under very low light intensities as a function of the transmittance properties of the OPV cell used (P2). P1 competed comparably (p > 0.05) with control in most growth and yield traits measured. In addition, shoot to root distribution was higher in P1 than control. RF reduced shoot and total biomass production of spinach in the field due to its inability to transmit other spectra of light. OPV-RF transmittance did not affect plant height (PH), leaf number (LN), and SPAD value but leaf area (LA) was highest in P2. Photochemical energy conversion was higher in P1, P2 and RF1 in contrast to control due to lower levels of non-photochemical energy losses through the Y(NO) and Y(NPQ) pathways. Photo-irradiance curves showed that plants grown under reduced light (P2) did not efficiently manage excess light when exposed to high light intensities. Bufflehead genotype showed superior growth and yield traits than eland across OPV and RF levels. It is therefore recommended that OPV cells with transmittance properties greater than or equal to 11% in BL and 64% in RL be used in APV systems for improved photochemical and land use efficiency.

Population density is an important determinant of crop yield. For optimum crop production, the best spacing requirement must be adopted. Although the recommended spacing requirement of mungbean is abundant in literature globally, there is no such information on studies conducted within derived savannah agroecological zone of southeast Nigeria, despite the crop’s usefulness as food, green manure, and nitrogen fixer. We hypothesized that the spacing requirement of mungbean may vary with genotype. Hence, this study was conducted to evaluate the response of three mungbean genotypes to four spacing types in derived savannah agroecology. The experiment was a split-plot design with genotype (Tvr18, Tvr65, and Tvr83) as the main plot treatment and plant spacing (30x10, 40x10, 30x15, and 40x15 cm) as the sub-plot treatment. Data were collected on 19 agronomic traits. Analysis of variance (ANOVA) showed that plant spacing of 30x10 cm influenced significantly higher (p<0.05) values in most agronomic traits measured while Tvr18 was higher in pod and seed attributes with higher seed-yield (0.80 t/ha) compared to Tvr83 (0.52 t/ha) which was the least. The interaction effect of Tvr18 by 30x10 cm gave a higher seed yield of (1.37) t/ha compared to Tvr83 by 30x10 cm (0.62 t/ha) which was the least. GGE biplot analysis showed a higher seed yield of the genotype-Tvr83 with wider spacing 40x15 compared to 30x10 cm.

Genotype by environment (G × E) interaction is a magnitude change in the performance of a genotype when grown in contrasting environments. The sensitivity of a genotype to different environmental conditions is an important determinant of its suitability for cultivation in a specific environment or across multiple environments. In many nations of the world, where the drive to achieve a net-zero CO₂ emission by 2030 has spurred significant investments in clean energy sources such as photovoltaics with a resultant conversion of some agricultural lands to photovoltaic facilities, there is a need to find the right balance between addressing the food and energy crises. Agri-photovoltaics (APV) offer a sustainable solution by allowing crops to grow underneath photovoltaic panels. However, selection efficiency and repeatability of APV experimental results could be marred by the presence of G × E interaction. The study objective was to identify mungbean genotype(s) with a high yield potential and broad adaptability across APV environments. Five mungbean (Vigna radiata L.) genotypes, Tvr18, Tvr28, Tvr65, Tvr79, and Tvr 83, were assessed under six contrasting APV environments, EPV-R, EPV-D, NPV-R, NPV-D, WPV-R, and WPV-D, at the Agri-PV Food and Energy Training Center, University of Nigeria, Nsukka. The experiment was a split-plot design, with the environment as the whole-plot factor while genotype was the sub-plot factor with five replications. The additive main effects and multiplicative interaction (AMMI) and the Finlay and Wilkinson joint regression analysis confirmed significant genotype, environment, and G × E interaction effects for mungbean seed yield. Two genotypes, Tvr28 and Tvr83 expressed broad adaptability to the APV environments with higher yields (2.60 and 2.50 t ha⁻¹), ranking first and second, respectively. In contrast, the Tvr79 genotype displayed the highest sensitivity (2.95) to environmental variation and was unstable across the environments with higher IPCA1 and ASV scores of −1.17 and 1.39, respectively. The EPV-R recorded the highest yield (2.61) with low interaction effect (0.38), whereas the WPV-D environment had the least yield (1.71) and was the most unstable (−0.48). Conclusively, the Tvr28 and Tvr83 genotypes and the EPV-R environment were the ideal genotypes and environment, respectively, and are therefore recommended for use in APV facilities.

Background and Objective: Mungbean is relatively unknown and underutilized pulse in Southeast Nigeria with enormous potential to eliminate hunger and malnutrition in the region. This study was carried out to evaluate, characterize and select promising mungbean genotypes based on morphological and agronomic traits in an attempt to increase the legume base and secure alternative sources of plant-based proteins for Nigerians. Materials and Methods: Ten mungbean accessions were characterized and evaluated between April to October, 2020 at the Department of Crop Science, University of Nigeria, in a randomized complete block design (RCBD) with four replications. Data were collected on 23 morphological and 21 agronomic traits. Results: The clear-cut variation in 21 of 23 morphological traits and 16 of 21 agronomic traits. The number of pods (NOP) per plant, number of seeds (NOS) per pod and seed yield were the most discriminating yield indices. The Tvr18 and Tvr79 recorded higher NOP per plant, NOS per pod and seed yield and were therefore selected for advancement to the next generation. The ten accessions were clustered into two distinct groups, cluster I and II, with 8 and 2 accessions, respectively. The Tvr83 showed uniqueness for a higher number of leaves (NOL), number of branches (NOB), NOP per plant (although with shorter pods) and smaller leaves compared to the other nine accessions. Conclusion: The two high yielding accessions, Tvr18 and Tvr79 could provide flatulence free proteins to Nigerians while, Tvr83 is a valuable candidate for improvement of Tvr18 and Tvr79 in any of these traits for which it showed superiority. APA-7 Style Ukwu, U.N., Oburu, B.N., Muojiama, S.O., Osadebe, V.O., Dauda, N., Adewuyi, S.O. (2023). Morphology and Agronomic Evaluation of Ten Mungbean (Vigna radiata L.) Accessions in Derived Savanna Agroecology of Southeast Nigeria. Asian Journal of Biological Sciences, 16(2), 110-120. https://doi.org/10.3923/ajbs.2023.110.120 ACS Style Ukwu, U.N.; Oburu, B.N.; Muojiama, S.O.; Osadebe, V.O.; Dauda, N.; Adewuyi, S.O. Morphology and Agronomic Evaluation of Ten Mungbean (Vigna radiata L.) Accessions in Derived Savanna Agroecology of Southeast Nigeria. Asian J. Biol. Sci 2023, 16, 110-120. https://doi.org/10.3923/ajbs.2023.110.120 AMA Style Ukwu UN, Oburu BN, Muojiama SO, Osadebe VO, Dauda N, Adewuyi SO. Morphology and Agronomic Evaluation of Ten Mungbean (Vigna radiata L.) Accessions in Derived Savanna Agroecology of Southeast Nigeria. Asian Journal of Biological Sciences. 2023; 16(2): 110-120. https://doi.org/10.3923/ajbs.2023.110.120 Chicago/Turabian Style Ukwu, Uchenna, Noble, Blessing Ngozika Oburu, Stella Ogochukwu Muojiama, Vivian Ogechi Osadebe, Nathaniel Dauda, and Solomon Oluwaseyi Adewuyi. 2023. "Morphology and Agronomic Evaluation of Ten Mungbean (Vigna radiata L.) Accessions in Derived Savanna Agroecology of Southeast Nigeria" Asian Journal of Biological Sciences 16, no. 2: 110-120. https://doi.org/10.3923/ajbs.2023.110.120

Fusarium wilt disease is a major biotic factor limiting watermelon production in the derived savanna agroecology of southeast Nigeria. The study hypothesized that variety could interact with the fungicide spraying regime to improve the agronomic performance of watermelon (Citrulus lanatus (Thunb) Matsum and Nakai). The objectives of the study were: to assess the effect of fungicide spraying regimes on disease incidence, severity, and agronomic performance of three watermelon varieties; and to identify and characterize the fungal causal organism of Fusarium wilt of watermelon in the derived savanna agroecology of southeast Nigeria. Three varieties of watermelon (Jubaly, red diamond, and sweet sangaria) and four fungicide spraying regimes (No spray, weekly, bi-weekly, and tri-weekly spray) were evaluated for agronomic performance, and disease incidence and severity in a 3 × 4 factorial in a randomized complete block design replicated thrice. Data were collected on phenological, growth and yield indices, and disease incidence and severity. Analysis of variance was done using Genstat 16^th edition and GraphPad Prism 9 was used to construct the graphs. Variety significantly affected agronomic traits as well as disease incidence and severity. The Jubaly variety performed better than other varieties in most of the growth and yield parameters measured despite recording higher disease incidence and severity scores. Weekly application of fungiforce recorded the lowest disease incidence (16.67, 16.67, and 50%) and severity (6.7, 6.7, and 10%) at 9, 10, and 11 weeks after planting, respectively. The interaction effect of the Jubaly variety and weekly spray was consistently higher in vine length, node number, fruit number, and fruit yield. Morphological isolation and identification of the fungal causal organism showed the presence of Fusarium species. Further molecular characterization by DNA extraction from the Fusarium isolate and sequencing using the Sanger sequencing method confirmed the presence of Fusarium equiseti. The basic local alignment search tool result showed 94–100% similarity with F. equiseti strain WZ-98 from the NCBI Gene bank. The organism was identified as F. equiseti based on the Phylogeny.