Reproductive mechanisms and pollen characterization in some accessions of an underutilized legume: (Sphenostylis stenocarpa Hochst Ex. A. Rich) harms

Studies on flowering, pollen, pod and seed characters, germination rate and seed set percentage were carried out on twenty five accessions of African Yam Bean (AYB). Self compatibility tests confirmed all the accessions as obligate selfers, while the reciprocal crosses were not successful. Germination rate, percentage seed set and pollen fertility were observed to be high in the accessions. Correlation analysis among the reproductive traits revealed that pod length, pod width, number of locules per pod and number of seeds per pod contributed significantly to the percentage seed set in all the accessions. Pollen fertility and seed viability were also observed to be high in all the accessions except in TSs23 where low pollen fertility, low seed viability and low percentage seed set were recorded. All the accessions produced tricolporate pollen grains. Pollen size ranged from 66.15 μm in TSs40 to 82.75 μm in TSs119, pollen fertility ranged from 53.39% in TSs23 to 95.30% in TSs119, seed set ranged from 83.32% in TSs90, 89.21% in TSs23 and 95.72% in TSs3. The germination rate ranged from 59.68% in TSs23 to 99.03% in TSs22. The percentage moisture content ranged between 4.38% in TSs22 and 11.43% in TSs119. Key words: Pollen characters, seed set, germination rate, self compatibility

Seasonal variations of physicochemical characteristics of brewery industry effluent and receiving water of Ikpoba-Oha Rivers, Benin City, Nigeria

The impact of the effluents from a Brewery industry on the water quality of Ikpoba-Oha River was carried out during wet and dry seasons, 2016. Water samples from three selected points in the river were analyzed for pH, temperature, total solids, total dissolved solids, Hardness, BOD, COD, DO, Chlorides, phosphates, sulphates. Samples were collected at three points designated as: point 1 (effluent), point 2 (upstream), and point 3 (downstream). The results of the analysis of the effluent obtained on both seasons were: pH (5.90-8.38), temperature (25.20oC-33.15oC), chlorides (12.0-129.2mg/l), phosphates (0.9-20.48mg/l), sulphates (3.30-53.0mg/l), nitrates (3.8-17.20mg/l), DO (2.3- 4.15mg/l), Total Hardness (12.10-425.6mg/l), Ca hardness (6.0-296.4mg/l), Total Solids (44.0-513mg/l), TSS (20- 159mg/l) and TDS (24-354mg/l).The levels of most of the parameters monitored are generally higher at the point of effluent discharged into water bodies and dispersed to less malign conditions downstream due to water dilution effect.Keywords: Physicochemical properties, Ikpoba River, Effluent, pH, Hardnes

Comparative Study on the Epidermal Features of Twelve Under-Utilized Legume Accessions

Seeds of six species of twelve accessions of miscellaneous legumes were obtained from the germplasm unit of the International Institute of Tropical Agriculture (IITA), Ibadan, Oyo State, Nigeria. The seeds were planted into plots of 5m long, spaced 1 meter apart at the botanical garden of the University of Agriculture, Abeokuta (UNAAB), Ogun State, Nigeria. Leaves of the plants were assessed for their genetic and phylogenetic relatedness through diagnostic epidermal studying of the cell shapes, anticlinal wall types and stomatal characteristics at the abaxial and adaxial surfaces. The cell shapes, anticlinal wall types and the stomatal characteristics revealed some correlations among the studied taxa. All the species were amphiostomatic possessing stomata on both the abaxial and adaxial surfaces. Proportions of the stomata distributions among the taxa were 75% (paracytic), 16.67% (anomocytic) and 8.3% (anisocytic) at both surfaces. There was no accession with diacytic stoma. Cell shapes were 75% polygonal, 25% irregular at the abaxial surfaces and 66.67%, 33.33% irregular and polygonal respectively at the adaxial surface. The prevalent anticlinal wall type was curved (41.67%) followed by curved/slightly straight (33.3%) and slightly straight (25%) at both surfaces. Result of the epidermal features of the studied taxa revealed some diagnostic characteristics that could be used for taxonomic decisio

Morphometric Analysis of some Species in the Genus Vigna (L.) Walp: Implication for Utilization for Genetic Improvement

The genus Vigna (L.) Walp is a large cosmopolitan leguminous genus comprising both cultivated and wild species. Vigna unguiculata (L.) Walp. (Cowpea) is an important food legume that is widely cultivated in the tropics, but its production and storage are hampered by insect pests. The present study evaluated the intra-and inter-specific morphological variabilities among 20 accessions of six Vigna species, comprising wild and cultivated species. The species are Vigna unguiculata (L.) Walp, V. vexillata (A. Richard), V. oblongifolia (A. Richard), V. ambacensis (Baker), V. luteola (Jacq.) (Bentham) and V. racemosa (G. Don) (Hutch and Dalziel). Thirty-one morphological characters involving qualitative and quantitative vegetative and reproductive traits were used for the evaluation. Multivariate analysis such as Pearson Correlation Coefficient (PCC), Principal Component Analysis (PCA) and Cluster Analysis (CA) were employed to evaluate the intra and inter specific variabilities. The paired-sample T test indicated significant differences among the 20 accessions (p#0.000, df = 19) in their morphometric traits. The relative significant correlation observed among some traits such as pod length, number of locules per pod and number of seeds per pod indicated their closeness and potential for genetic improvement of cowpea. The PCA showed that reproductive traits such as days to 50% flowering (0.984), days to 50% ripe pod (0.993), number of pods per peduncle (0.340) and 100-seed weight (0.132) are the major traits that accounted for the variations among the species. The UPGMA using the average (between groups) segregated the 20 accessions into two main clusters, cluster I (comprising mainly wild Vigna species) and cluster II (comprising both wild and cultivated species). The taxonomic affinities and genetic diversity among the species are of great importance in the utilization of the species for food and nutrition, fodder for ruminant animals, cover crop for rotational farming and more importantly genetic improvement of cowpea

Fruit Morphometric and RAPD Evaluation of Intraspecific Variability in Some Accessions of African Yam Bean (Sphenostylis stenocarpa Hochst. ex. A. Rich. Harms)

African Yam Bean (AYB) (Sphenostylis stenocarpa, Hochst. ex A. Rich, Harms) is an indigenous underutilized legume mainly grown in Sub-saharan African as a source of protein. Intraspecific variability studies were carried out on 10 accessions of AYB obtained from the International Institute of Tropical Agriculture (IITA) Ibadan, Nigeria. Fourteen (14) fruit morphometric characters and nine (9) arbitrary RAPD primers were employed for evaluation of genetic intra-specific variability among the accessions. A total of 410 bands were generated with 261 (63.66%) polymorphic bands. There is significant correlation among some reproductive characters; days to 50% flowering, pods per peduncle, number of locules per pod, number of seeds per pod, pod length and seed set percentage. These characters represent good markers of the taxon suitable for breeding and genetic improvement purposes. Morphometric and RAPD cluster analysis using UPGMA resulted in a dendrogram each; with membership similarity ranging from 72% to 93%. Two accessions (TSs56 and TSs94) recorded higher level of similarity index of 93% based on RAPD profiling. The morphometric evidences shows inherent stability of AYB across varied eco-geographical settings, which demands further investigation and exploitation. However, the RAPD evidences show that the species have evolved and adapted to distinct geographical setting with a clear Nigeria and Ghana demarcation. This fact can be engaged to guide future studies, germplasm collection, characterization, documentation, utilization and conservation of AYB to boost knowledge and awareness on the genetic diversity and utility of the species

Morphological Diversity and Cytological Studies in Some Accessions of Vigna vexillata (L.) A. Richard

Aim: The objectives of this study were to characterize and evaluate intraspecific relationship among twenty-six accessions of Vigna vexillata (L.) and work out interrelationship among the morphological traits which could be used for genetic improvement of cowpea, V. unguiculata (L.) Walp. Study Design: Field experiment was laid out in blocks of five buckets per accession in a row giving a total of 260 plants. Place and Duration of Study: At the experimental field of the Department of Biological Sciences, Covenant University, Ota, Ogun state, Nigeria, during the dry planting season (September – December, 2012). Methodology: A total of 26 traits comprising 18 quantitative and 8 qualitative traits of the vegetative, floral, pod and seed were evaluated using descriptive statistics, Pearson Correlation Coefficient (PCC), Principal Component Analysis (PCA) and Cluster Analysis (CA). Mitotic chromosome counts and meiotic behaviour were studied using root tip cells and pollen mother cells from young flower buds. Results: The analysis of variance showed that all quantitative morphological characters were significantly different among the accessions (P = 0.01) except stipule length and width. There were significant correlations among characters such as calyx lobe length, standard petal length and width, peduncle length, days to 50% flowering, days to 50% pod maturity, pod length and width, number of locules per pod, number of seeds per pod, and 100-seed weight which could be used for breeding and conservation purposes. The first six principal components accounted for 89.84% of the total variance. The cluster analysis segregated the 26 accessions into three main clusters; cluster I (15 accessions), cluster II (10 accessions) and cluster III (1 accession). Mitotic chromosome counts of 2n = 22 were recorded for all the accessions and meiosis was observed to be normal with the formation of eleven bivalents (n = 11). Conclusion: The intraspecific variabilities indicates plasticity in the genomes of the studied accessions, with high correlations among the morphological characters which are common to all accessions, thus justifying their grouping as a species. The morphological and reproductive attributes displayed by accessions TVnu93 and TVnu97 in terms of plant vigour, early flowering and pod maturity, longer pods and relatively high 100-seed weight made them good potential candidates in breeding for host plant resistance in cowpea

Characterization of Vigna vexillata (L.) Richard from Six African Countries

Vigna vexillata (L.) Richard is a wild relative of cowpea characterized by heavy pubescence of the leaves, stems and pods which could be utilized for genetic improvement of cowpea V unguiculata (L.) Walp. Twenty-six (26) accessions collected from six African countries; Cameroun, Zaire, Ghana, Swaziland, Congo and Nigeria were obtained from International Institute of Tropical Agriculture (liT A), Ibadan, Nigeria for morphological and cytological characterizations. Twenty-four morphological characters involving eighteen quantitative and six qualitative characters were used for intra-specific variabilities among the accessions. Young bud flowers were collected at the flowering stage for meiotic and mitotic chromosome behaviour of the accessions. The results showed significant differences among vegetative and floral characters (p::::: 0.000) while pod and seed characters do not show much variability. The high significant correlation among characters such as calyx lobe length, standard petal length and width, peduncle length, days to 50% flowering, days to pod maturity, pod length and width, number of locules per pod, number of seeds per pod, and 1 00-seed weight indicates their suitability for breeding and genetic improvement purposes. The cluster analysis using the UPGMA method segregated the 26 accessions into three main clusters; cluster I (super group of 16 accessions), cluster II (9 accessions) and cluster III (1 isolated accession). All the accessions analysed for cytological relationship presented 2n = 22 chromosomes as previously reported for the genus Vigna. Chromosomes paired as bivalents and regula

Evaluation of tropical maize hybrids under drought stress

The performances of plants and seedlings of 14 tropical-adapted, registered maize hybrids were evaluated under drought stress to assess genotype suitability for off-season planting and to identify parental materials for developing drought tolerant hybrids from locally adapted germplasm. Field evaluation was done at a rain forest location (Ikenne, Ogun State, Nigeria) on irrigated plots under well-watered and water-deficit conditions during the dry period of 2002/2003 cropping season. Data was collected on total biomass and grain yield. Drought stress tolerance index (DSTI) and harvest index (HI) were estimated from total biomass and grain yield data. Hybrids 2016-1 and 2016-6 had highest total biomass and grain yield under water deficit conditions as well as DSTI values above 0.9. Other hybrids with satisfactory performance in terms of biomass and grain yields under drought stress had DSTI values approximating 0.6 and above. From the seedling evaluation, correlation analysis of number of rolled seedling leaves with field stress tolerance indices was significant. Based on number of rolled leaves, hybrid 2016-6 had the least value, ranking it the most tolerant, but based on multiple seedling traits including seedling height, total seedling biomass, leaf chlorophyll content and leaf stay green ability (SGA), hybrids 9033- 26, 0103-11 and 9022-13 were high performers. All hybrids with satisfactory seedling performance also had DSTI values from the field evaluation that were approximately or above 0.6. The results emphasized the usefulness of DSTI as a useful index for determining drought stress and suggest that maize hybrids with DSTI values around 0.6 from field trials have potentials for satisfactory productivity under drought stres