The family Geminiviridae comprises 15 genera and over 500 species of diverse plant-infecting viruses. Previous studies on this virus’s diversity primarily focused on the members’ selection without considering the entire genomic divergence. This study presents comprehensive comparative genomic analyses and a global distribution map using 17,718 complete genomes and 28,185 geminivirus-associated metadata records. Intergeneric pairwise identity among monopartite and Begomovirus DNA-A is ≥ 40%, while interspecies identity among Begomovirus DNA-B is ≥ 41%, corresponding to genetic variations of ≤60% and ≤59%, respectively. Begomovirus and Mastrevirus are the only genera detected across all continents, with Asia exhibiting the highest genus diversity (11 genera). However, in Africa, geminiviruses from six genera are more broadly distributed across individual countries. To our knowledge, this is the first geographical map constructed using all genera from the Geminiviridae family. Phylogenetic reconstructions of complete genomes, coat proteins, and replication-associated proteins (Rep) underscored distinct clustering patterns consistent with genus-level classification but revealed exceptions, including misclassified viral species and potential new taxa. Notably, French bean severe leaf curl viru s with accession KC699544 was reclassified from Capulavirus to Begomovirus with the proposed name Corchorus yellow vein mosaic virus. Additionally, two unclassified begomovirus-like viruses, named “begomovirus spathoglottis 1” and “2,” are proposed for reclassification within Maldovirus under the tentative names “maldovirus spathoglottis 1” and “2.” The Begomovirus Rep showed phylogenetic affinity with Rep from Maldovirus, Curtovirus, Turncurtovirus, and Topocuvirus, supporting potential evolutionary relationships among these genera. Recombination analyses confirmed high-frequency interspecies and intergeneric recombination events, predominantly involving Begomovirus , underscoring its pivotal role in geminivirus evolution. Furthermore, we hypothesized specific vector transmission: Opunvirus , Welwivirus , and Topilevirus are transmitted via treehopper species, whereas Citlodavirus and Eragrovirus are transmitted via leafhopper species. Accurate identification and classification of plant viruses and their transmission vectors are essential for developing effective surveillance and management strategies to safeguard global agriculture.

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.

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

Climate change is affecting the dynamics of crop production globally. Water is the most critical climatic factor influencing crop productivity, and water scarcity is projected to rise within the next decade due to climate change. The need arises to develop climate-resilient cultivars that can tolerate intermittent water shortages to ensure food security. The objective of this study was to assess the response of mungbean accessions to intermittent water shortages in a tropical environment. Ten mungbean accessions were evaluated for agronomic and physiological responses under no water stress (WS) (I1), 3-day intermittent WS (I3), and 7-day intermittent water-stress (I7) conditions in a split-plot design replicated thrice. Data on agronomic and physiological traits were analyzed. Accessions, WS, and interaction of accession and WS significantly affected the phenology, growth, and yield of mungbean (P < 0.05). The accessions generally responded better to I1 and I3 conditions in contrast to the I7 condition. The dendrogram report suggested that the ten accessions evolved from two parental lines. Growth and yield traits were significantly decreased by I7, but I3 was comparable to I1 in all yield-contributing traits measured (P > 0.05). Therefore, irrigating once in 3-days is sufficient for mungbean during dry spells. The accessions Tvr28, Tvr32, and Tvr83 were the best in grain yield and recorded the least reduction in relative water content and stress tolerance index under I7 and were, therefore, recommended for use in drought-prone areas. Tvr83 was distant from the others making it an excellent prospect for a mungbean improvement program, especially if traits such as a high leaf, pod, and seed number are desired. The findings of this study are indispensable in the struggle to mitigate the unfavourable effects of climate change on food security. It is particularly more relevant to the over 163 million people across the globe who currently experience unprecedented dry spells compared to 50 years ago. It provides a renewed hope that some accessions of mungbean can tolerate intermittent WS to a reasonable degree and still produce appreciable yields.

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.