Agro-ecological Zone Of Nigeria Research Articles

Farmers Utilization of Climate Change Adaptation Strategies Across Selected Agro-Ecological Zones in Nigeria

This study examined farmers’ level of use of climate change adaptation strategies across selected agro-ecological zones in Nigeria. Edo and Ondo States were selected for the study with three major agro-ecological zones. A multi-stage sampling procedure was used. The correlation analysis revealed a significant relationship between year of education and level of use of adaptation strategies (r = 0.15, P = 0.02). The result of Analysis of Variance (ANOVA) revealed that significant differences existed in most of the adaptation strategies employed except planting different varieties (F = 1.672, P = 0.190), intercropping (F = 0.646, P = 0.525), crop rotation (F = 2.436, P = 0.090) and migration to different sites (F = 0.661, P = 0.517). The study recommended that the issue of climate change should not be taken lightly by all stakeholders as its effect differs among various agro-ecological zones.

Abundance and diversity of insects associated with stored grains and tamarind in Nigeria

Detailed information on insect pests of stored grains in Nigeria is lacking. A two-year survey was conducted to determine the species composition and abundance of insects associated with maize, millet, rice, sorghum and tamarind in eighteen locations across five agro-ecological zones in Nigeria. Sixteen coleopteran, lepidopteran and hymenopteran species were associated with stored products, with high species richness on cereal grains but low species richness on tamarind. Most of these insects are polyphagous on cereal grains, whereas the tamarind weevil Sitophilus linearis (Herbst, 1797) (Curculionidae), and Caryedon serratus (Oliver, 1790) (Chrysomelidae) were found only on tamarind in this study. The maize weevil Sitophilus zeamais (Motschulsky, 1758), rice weevil Sitophilus oryzae (Linneaus, 1763), lesser grain borer Rhyzopertha dominica (Fabricius, 1792) (Bostrichidae), rusty grain beetle Cryptolestes ferrugineus (Stephens, 1831) (Laemophloeidae) and red flour beetle Tribolium castaneum (Herbst, 1797) (Tenebrionidae) were most abundant on stored grains. The tamarind weevil, C. serratus and the sawtoothed grain beetle Oryzaephilus surinamensis (Linneaus, 1758) (Silvanidae) were most abundant on tamarind. The hymenopterans Theocolax elegans (Westwood, 1874) (Pteromalidae), Anisopteromalus calandrae (Howard, 1881) (Pteromalidae) and Cephalonomia waterstoni (Gahan, 1931) (Bethylidae) were the dominant parasitoids of larvae and pupae of the storage pests. Simpson index of diversity of insect species across locations ranged from low (0.63) to high (0.89).

Combining Ability and Heterosis for Endosperm Carotenoids and Agronomic Traits in Tropical Maize Lines.

Provitamin A enrichment of staple crops through biofortification breeding is a powerful approach to mitigate the public health problem of vitamin A deficiency in developing countries. Twenty-four genetically diverse yellow and orange endosperm maize inbred lines with differing levels of provitamin A content were used for the analysis of their combining ability. Each inbred line was developed from crosses and backcrosses between temperate and tropical germplasm. The inbred lines were grouped into different sets according to their provitamin A levels and were then intercrossed in a factorial mating scheme to generate 80 different single-cross hybrids. The hybrids were evaluated in field trials across a range of agroecological zones in Nigeria. The effect of hybrids was significant on all the measured provitamin A and non-provitamin A carotenoids and agronomic traits. While the effect of genotype-by-environment (GxE) interaction was significant for almost all traits, it was a non-crossover-type interaction for carotenoid content. Partitioning of the variances associated with the carotenoid and agronomic traits into their respective components revealed the presence of significant positive and negative estimates of general combining ability (GCA) and specific combining ability (SCA) effects for both carotenoid content and agronomic traits. The preponderance of GCA effects indicates the importance of additive gene effects in the inheritance of carotenoid content. We found F1 hybrids displaying high parent heterosis for both provitamin A content and agronomic performance. Our study demonstrates that provitamin A biofortification can be effectively implemented in maize breeding programs without adverse effects on important agronomic traits, including grain yield.

Wide circulation of peste des petits ruminants virus in sheep and goats across Nigeria.

Peste des petits ruminants (PPR) is a highly contagious viral disease that mainly affects goats and sheep in Asia, Africa and the Middle East, and threatens Europe [R.E.1]. The disease is endemic on the African continent, particularly in West Africa, and is a major factor driving food insecurity in low-income populations. The aim of this research study was to carry out surveillance, genetic characterisation and isolation of recently circulating PPR viruses (PPRV) in sheep and goats from the six agro-ecological zones of Nigeria. A total of 268 post-mortem tissue samples of lung and mesenteric ganglia were collected from clinically suspected sheep and goats in 18 different states, of which five never previously sampled. The presence of PPRV was confirmed using a reverse-transcription coupled with a polymerase chain reaction (RT-PCR) assay. A total of 72 samples, 17 sheep (6%) and 55 goats (21%), were found to be PPR positive. Positive samples were distributed in almost all states, except Kano, where PPR was detected in previous studies. The PPRV-positive samples were further confirmed by sequencing or virus isolation in areas where the infection had never previously been detected. These results confirm the active circulation of PPRV across all six agro-ecological zones of Nigeria, and consequently, the need for introducing strict measures for the control and prevention of the disease in the country.

Morphometric and Genomic Characterization of Toxigenic Aspergillus Isolates Associated with Poultry Feeds and Feed Ingredients from Five Agro-Ecological Zones of Nigeria

Introduction: Toxigenic aspergilli are storage contaminants of poultry feeds and feed ingredients which produce secondary metabolites known as mycotoxins in these products. This research is aimed at detecting and characterizing mycotoxin producing aspergillus species present in feeds given to poultry birds and in the ingredients used in the production of these feeds.
 Method: A total of 102 samples of feed (n=30) and feed ingredients (n=72) were collected across 5 agro-ecological zones of Nigeria and analyzed for toxigenic Aspergilli using morphometric and molecular genomic characterization techniques. Different mycological media was used for isolation, by deploying pour plate method. The Aspergilli isolates morphometric identity were characterized using macroscopic and microscopic observed features. The isolated Aspergillus species were further characterized molecularly using genomic characterization protocols.
 Results: The results of the morphometric characterization indicated that nine (9) Aspergillus species were detected in the feed and feed ingredients, with Aspergillus flavus having the highest rate of occurrence among the isolates. Furthermore, the genomic typing using internal transcribe spacer (ITS) as a barcode, as well as comparison of the fungal isolates with other Aspergillus species in the genebank showed 99-100% similarity. Also, toxigenic gene typing indicated that some of the A. flavus were toxigenic with the detection of the following genes Nor-1, ver-1, OmtB and AflR.
 Conclusion: The findings of this study showed that toxigenic Aspergilli isolates are present in both poultry feed and feed ingredients from 5 agro-ecological zones in Nigeria and poses great public health issues.

Influence of land-use and soil depth on the soil organic carbon in two agro-ecological zones of Nigeria

Influence of land-use and soil depth on the soil organic carbon in two agro-ecological zones of Nigeria

Body weight and Morphometric traits characterization of Some Nigeria Homing Pigeons (Columbia livia).

Growth traits characterization of Nigeria homing pigeons was done using one hundred and thirty eight (138) birds from three locations (LCT) of different agro-ecological zones in Nigeria [Kebbi (KEB):North West; Ilorin (ILR): North Central and Osogbo (OSG): South West]. Parameters measured were body weight (BW) in gram and morphometric body parameters in cm viz. Head length (HL), beak length (BL), neck length (NL), body length (BL), body girth (BG), wing length (WL), body height (BH), thigh length (TL), drumstick length (DL) and keel length (KL). The results showed that, significant (p<0.05) differences existed between body weight and body parameters measured except BL. ILR pigeons had significantly (p<0.05) higher BW (263.51g) compared to OSG (204.15), but similar (p>0.05) to KEB (249.76g); the morphometric body parameters measured showed that HL, BG and WL values were significantly (p<0.05) higher in ILR; OSG had significantly (p<0.05) higher values for KL, while KEB pigeons had significantly (p<0.05) higher values for BL, NL, BH, TL, DL, and SL. Positive and significant correlations (p<0.01, 0.05) exists between locations, NL, SL and BH; BW was negatively correlated with locations with a significant (0.01) value of -0.58. PCA shows the clustering of growth traits from 18.94 to 25.14% under PC1 and 2, canonical discriminant functions gouped KEB and OSG with 56.60%; ILR and KEB with 43.60% while hierarchical clustering shows that KEB homing piegons are distinct from those of ILR and OSG. This results shows that locations have significant effects on growth traits in Nigeria homing pigeons.

Defoliation Effects on Growth, Development and Yield of Okra (Abelmoschus esculentus) Under an Irrigation Regime

An experiment was conducted at Research and Demonstration Farm of Agricultural Science Department, Federal College of Education, Pankshin located in the Northern Guinea Savanna Agro-ecological Zone of Nigeria to investigate defoliation effects on morphological characters and yield attributes of okra (Abelmoschus esculentus) carried out during 2015 and 2016 dry season. The experiment comprised five levels of defoliation viz: 0% (control), 30%, 60%, 90%, and 100%. The experiment was laid out in identical Randomized Complete Block Design (RCBD) with six replications. Results revealed that defoliation had significant effect on the studied crop characters and yield. Most of the parameters like plant height, stem girth; number of leaves, leaf area, and yield parameters decreases which are a function of increasing defoliation levels intensity. Defoliation at 0% and 30% were tolerable for okra plant growth and development, while at 90% and 100% was detrimental to plant growth and yield. Hence, defoliation at 30% is recommended to meet farmers’ pod and leaf requirement.

Evaluation of seed of white yam (Dioscorea rotundata Poir) cultivars as influenced by minisett sizes in the Southern Guinea Savannah agro-ecological zone of Nigeria

Evaluation of seed of white yam (Dioscorea rotundata Poir) cultivars as influenced by minisett sizes in the Southern Guinea Savannah agro-ecological zone of Nigeria

A recalibrated and tested LINTUL-Cassava simulation model provides insight into the high yield potential of cassava under rainfed conditions

Accurate assessments of the yield potential of cassava are needed to analyse yield gaps, define yield targets and set benchmarks for actual yields in Nigeria. This study evaluated the crop model LINTUL-Cassava under assumed potential growth and water-limited conditions in Nigeria. On-farm experiments were conducted at six locations across the three major cassava growing agro-ecologies of Western Africa (Tropical Rainforest – Ogoja and Ikom in Cross River state, Rainforest Transition Savanna – Ekpoma in Edo state and Guinea Savanna – Otukpo in Benue state) during two subsequent seasons (2016 – 2018). Treatments included fertilizer rates calculated to support the assumed potential yields of 90 t fresh storage root yield ha−1 y−1 (equivalent to 32 t DM ha−1, produced in a growing season of 12 months). Light interception (LI) and leaf area index (LAI) were measured each month. The weights of leaves, stems and storage roots were measured at 4 and 8 months after planting and at harvest, and radiation use efficiency (RUE) calculated. The Edo experiment from 2016 was without drought stress and was used to parameterise LINTUL-Cassava and calibrate assimilate partitioning as function of temperature sums. The average fraction of light intercepted during the season was 80 %, with a light extinction coefficient of 0.67 and a RUE of 2.8 g DM MJ−1 intercepted photosynthetically active radiation (IPAR). After calibration, the LINTUL-Cassava model described the crop growth and observed patterns of LAI well in the experiments in Cross River and Edo (2017). Simulated and observed storage root yield at 4 MAP (vegetative period), 8 MAP (mid-season) and at harvest were strongly correlated (R2 of 0.92), with a RMSE of 4.93 t DM ha−1. We ascertained that RUE of cassava was much higher than previously observed in Africa, with an average storage root yield of 39 ± 7 t DM ha−1. Consequently, potential yields are greater and yield gaps larger than expected or previously reported. We conclude that the LINTUL-Cassava model can provide an adequate estimate of storage root yield across major cassava growing agroecological zones in Nigeria under rainfed conditions.

Soil organic carbon concentration and stock of arable land use of two agro-ecological zones of Nigeria

Soil Organic Carbon (SOC) dynamics study in arable land use at different agro-ecological zones is important for recommendation of sustainable land use management practices against detrimental practices. This will provide insight on how to enhance SOC sequestration, improve soil quality and mitigate impact of climate change in different agro-ecological zones. This study was conducted at two agro-ecological zones of Nigeria; upland rainforest (Ado-Ekiti) and southern guinea savanna (Kabba) to evaluate SOC sequestration under arable land use. From the two agro-ecological zones, 1 ha (ha) of land was marked out, five soil samples were randomly collected at four different depths (0–15, 15–30, 30–45, and 45–60 cm) for SOC sequestration study. Higher SOC concentration and stock were observed at Ado-Ekiti site over Kabba site was due to best soil management practices like soil organic and inorganic fertilizers application and incorporation of crop residues. SOC concentration distribution varied greatly (%CV > 35%) and decreased with depth at the two agro-ecological zones. SOC stocks ranged from 6.59 t ha −1 to 24.97 t ha −1 and decreased with depth in similar trend with SOC concentration. Generally, at both sites, soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP) decrease with increasing depth especially to 45 cm depth while soil pH increase with increasing depth. Both SOC concentration and stock were observed to have significant positive correlation ( P < 0.01; P < 0.05) with SOM ( r = 1.000** and 0.996**; and r = 0.991** and 0.707**) and TN ( r = 0.936** and 0.934**; and r = 0.992** and 0.691**) at Ado-Ekiti and Kabba sites respectively. This indicated that increase in SOM and TN were associated with increase in SOC stock and concentration. Maximum value (20.33%) of exchangeable sodium percentage (ESP) of above critical value of 15% was recorded at Ado-Ekiti site which requires that soil be managed against sodicity. There was significant difference ( t = 2.975**) between the overall mean SOC stocks (14.83 and 9.15 t ha −1 at Ado-Ekiti and Kabba sites respectively) at two agro-ecological zones. Thus, adoption of better soil management practices will enhance SOC sequestration and soil quality at the two agro-ecological zones.

Growth assessment of juvenile oil palm (Elaeis guineensis Jacq.) intercropped with fruit vegetables in a rainforest zone of Nigeria

Improper intercropping of Elaeis guineensis with other crops has impaired the growth and development of the oil palm due to competition for environmental resources. The study was conducted to investigate the impact of intercropping on the growth of juvenile oil palm for 2 years. The research commenced during the rainy season of 2016 at an established juvenile oil palm plantation in Ala, Akure-North Local Government of Ondo State. Four fruit vegetables were intercropped separately within the alley of the plantation at 1, 2 or 3 m away from the oil palms in a randomized complete block design. Growth parameters of the juvenile oils were assessed. Results revealed that at 16 weeks after intercropping (WAI), the intercropped oil palm recorded better growth performance with higher canopy spread, number of frond, number of leaflets and trunk height (218.20, 37.00, 87.48 and 38.17 cm) respectively, than the sole oil palms (214.67, 32.83, 72.89 and 31.67 cm) respectively. There were no significant difference in all the growth parameters examined except canopy height (p &lt; 0.05). Juvenile oil palm cultivated in rainforest agroecological zone of Nigeria can be intercropped with fruit vegetables without any deleterious effect when intercropped at minimum of 1 m away from the oil palms.

Quantitative Assessment of Trace and Macro Element Compositions of Cassava (Manihot esculenta) Storage Roots Enriched with Β-Carotene as Influenced by Genotypes and Growing Locations

Cassava’s important mineral contents depends on some factors, including genetic and growing locational factors. The study aimed to evaluate the influence of genotype and growing locations on the mineral concentrations in yellow-fleshed cassava root genotypes. Twenty-five pipeline yellow-fleshed cassava genotypes and three white-fleshed varieties (check samples) were planted at five different experimental fields for two seasons, each representing the major agroecological zones in Nigeria. Standard laboratory protocols were employed in the sampling to ensure zero contamination, and the trace and macro elements were determined using the inductively coupled plasma optical emission spectroscopic method (ICPOES). The trace and macro elements identified in all the genotypes and varieties investigated were Fe, Mn, B, Cu, Mo, Co, Ni, Zn, and Al; Ca, Mg, Na, K. P, and S respectively. Genotype and growing location had a highly significant (p &lt; 0.05) effect on all the trace elements except Ti and Cr. However, there was no interactive effect between genotype and growing location on all the trace elements except for Pb and Zn. Among the explanatory variables, the variable growing location was the most influential on macro and trace elements. Conclusively, genotypes 01/1442 and 01/1273 have outstanding trace and macro element concentrations.

Establishment and Early Regeneration of Stem Cuttings from Chicken Weed (&lt;I&gt;Portulaca quadrifida&lt;/I&gt; L.) as Influenced by Soil Types

Differences in the ability of soil are a requirement for early regeneration of a plant. It was a pot experiment carried out at Sokoto in the Sudano Sahelian agro-ecological Zone of Nigeria. The objective was to investigate the regenerative ability of stem cuttings of Chicken weed on different soil type as a strategy for the weed control. The experimental set up was 3 × 7 factorial arrangement in a Completely Randomized Design. The treatments consisted of seven stem cuttings types namely (NLA-D - node leaf attached at distal stem location, NLR-D - node leaf removed from distal stem location, NLA-P- node leaf attached at proximal stem location, NLR-P- node leaf removed from proximal stem location, IN-D - internodes at distal stem location, IN-P- internodes from proximal stem location and SRA- stem roots attached) and three soil textural class (Sandy, Silty clay and Loamy sand). Result revealed that Silty clay recorded highest number of survived plants. Plant height, number of leaves, nodes, internodes and internodes length were greatly favoured by sandy soil. Loamy sand supported the earliness to leaf emergence and flowering. NLA-D supported the early regeneration of the plant in all stem cuttings tested, but earliness to leaf emergence and flowering was better with NLAP. This finding gave information that Chicken weed regenerate profusely and control measures should be administers to save target crop from yield losses.&#x0D; Keywords: distal, proximal, stem cuttings, soil textural class, regeneration

Morphometric studies on Nigerian honeybee Apis mellifera adansonni L. workers of rainforest and Sudan agro-ecological zones of Nigeria

The threat to honeybees, Apis mellifera occasioned by anthropogenic activities often reduced variations and loss of diversity globally, hence the need to conserve the existing honeybee populations. Fifteen morphological characters were measured for variation on four hundred (400) worker honeybee samples purposively collected from two agro-ecological zones of Nigeria. Inferential statistics Analysis of Variance, SNK and t- test (α = 0.05) and dendrogram of morphological proximity based on wings and proboscis length was also constructed using PAST 2.14 version analysis as appropriate for data collected. Results showed that significant morphological variation (p < 0.05) existed within honeybees in locations studied in each agro-ecological zones and among Apis mellifera populations in both Sudan and rainforest ecological zones in Nigeria. A. mellifera L. collected from areas of Sudan vegetation (mountainous zone) showed significant higher value of several morphological characters as compared to those found in rainforest zone (sub-mountainous zone). Whereas high morphological similarities were observed in Sudan honeybee populations, distant relatedness of Emure (rainforest) honeybees however were recorded (CV = 0.34). The study concluded that ecotypes exist in Nigerian honeybees as a result of significant morphometric variations which could have significant impact in future bee breeding programmes with respect to A. mellifera L. in Sudan and rainforest agroecological zones of Nigeria. It is recommended that activities that will enhance honeybee conservation should therefore be encouraged.

Investigation of Trends in Agricultural and Meteorological Drought in Nigeria

Investigating the trend in meteorological and agricultural drought is important in water resources management. Drought affects agriculture, water resources and the ecosystems of Nigeria. This study investigated the trend in meteorological and agricultural drought in the guinea savannah, sudan savannah and sahel savannah agro ecological zones in Nigeria by using SPI (standardized precipitation index), SPEI (standardized precipitation and evapotranspiration index) and SSI (standardized soil moisture index) indices. SPI considers only precipitation, SPEI considers both precipitation and potential evapotranspiration to determine drought and SSI considers soil moisture to evaluate soil moisture deficit for both short and long period. Precipitation data (1981-2015) was obtained from Nigerian Meteorogical Agency (NIMET) and soil moisture data (1981-2015) for 3 weather stations (1 from each zones) was obtained from the Climate Prediction Center (CPC). The result showed that; (1) Trend analysis revealed that the hypothesis of no trend was rejected in the three agro-ecological zones studied; (2) There was an observed significant drying trend at 95% significant level; (3) Over the three zones, the drought indicators showed significant trend; and (4) Comparison analysis of the 3 drought indices used in this study shows that SPI and SPEI are more consistent in the three zones showing relative correlation compared to SSI.

Baseline fertility status of a gravelly Alfisol in a derived savannah agro-ecological zone of Nigeria

Abstract Farmers have not tested their soils for nutrient status and therefore are unaware of the fertility status of their soils. Therefore, a baseline fertility survey of 50 hectares of land of a gravelly Alfisol in the Teaching and Research Farm of Landmark University, Omu-Aran, Kwara State, Nigeria was carried out with a view to identifying soil health constraints and site-specific sustainable land management practices for optimizing crop production. Standard field protocols and laboratory analytical procedures were employed for all sample parameters measured. Results show that the soil textural classes vary from sand to loamy sand, exchangeable acidity, Ca, Mg, K, and Na and the effective cation exchange capacity has the surface and subsurface soil values of 0.0–0.92 and 0.00–0.89 cmol kg−1, 1.6–7.7 and 2.0–5.8 cmol kg−1, 1.2–11.5 and 0.7–8.0 cmol kg−1, 0.09–0.33 and 0.09–0.43 cmol kg−1, 0.0–0.16 and 0.04–0.16 cmol kg−1, 7.2–12.10 and 0.9–12.5 cmol kg−1, respectively. P values lie in the ranges of 2.5–68.9 mg kg−1 and 2.0–37.7 mg kg−1 in the surface and subsurface soils, respectively, organic C values were 0.86–2.81% and 0.68–3.49%, respectively, in the surface and subsurface soils while the values of N were 0.12–0.61% in the surface and 0.11–0.56% subsurface soils. Land evaluation shows that the soils of the project site are very fragile and poor in native fertility. Compound fertilizers low in nitrogen contents but high in phosphorus and potassium are recommended for gravelly Alfisol in a derived savannah ecological zone of the Kwara State, Nigeria to avoid a nutrient imbalance that may create artificial deficiencies of otherwise adequate nutrient elements.

Assessing the sensitivity of standardized precipitation evapotranspiration index to three potential evapotranspiration models in Nigeria

Drought indices are very essential in monitoring and planning for drought occurrences. Though many indices have been established over the years, it is expected that proper investigation should be done using these indices to know the ones that can better characterize the drought condition of a region or country. The current study evaluated the performance of three potential evapotranspiration models (Hargreaves, Penman-Monteith and Thornthwaite) as inputs into Standardized Precipitation Evapotranspiration Index (SPEI) in regards to identified historic drought events for five agroecological zones in Nigeria. The computation of the indices was done using either one or more of the monthly time series of rainfall, minimum, maximum and mean temperature, sunshine hours and wind speed from 1981 – 2015 at five timescales (1, 3, 6, 12 and 24 months). Although all the models correlated significantly with one another, SPEI-H (Standardized Precipitation Evapotranspiration Hargreaves) vs SPEI-P (Standardized Precipitation Evapotranspiration Penman-Monteith) show higher correlation for all timesteps than SPEI-H vs SPEI-T (Standardized Precipitation Evapotranspiration Thornthwaite) and SPEI-P vs SPEI-T. The efficiency of the indices in identifying historic drought episodes: 1983 – 1985, 2007 and 2011 was examined using information obtained from Emergency Events Database (EM-DAT) and previous literature on drought studies in Nigeria. Drought onsets, severity and duration determined by the indices were compared with that of the EM-DAT. All the three indices show earlier onset for both 3- and 12- month timesteps than that of EM-DAT, but indicated a significant difference in severity and duration during the 1983 – 1985 drought episode for 12-month timestep. Though SPEI-P has a higher comparative predictive ability as indicated by EM-DAT, it was discovered that SPEI-H is a good alternative for regions where there is a paucity of data.

Growth and Yield of Two Maize Varieties under the Influence of Plant Density and NPK fertilization

This study assessed growth and yield performances of maize under the influence of inorganic fertilizer, population density and variety using the following treatments: maize varieties DMR-ESR-Y and Suwan- 1-SR; 70 × 30cm and 100 × 40cm plant spacing; 0, 60 and 120 kg NPK/ha . Data were collected on number of leaves per plant, plant height, ear height, leaf area, leaf area index, days to 50% flowering, days to tassel and silk appearances, stem dry mass, root dry mass, cob mass, number of kernel rows, number of kernels per cob, harvest index, treatment yield per hectare. The result showed that combination of 120kgN/ha, DMR-ESR-Y and 47, 619 plants/ha improved root, shoot, leaf sheath and plant dry masses, cob length, cob diameter, shelling percentage, moisture content at harvest, harvest index, number of cobs per plant as well as number of kernels per row. It is, therefore, recommended that combination of 120kgNPK/ha, DMR-ESR-Y and 47,619 plants/ha should be used for better maize production to cater for the ever increasing population of consumers in Southern Guinea savannah agroecological zone of Nigeria and other area with the same climatic and edaphic conditions. &#x0D; Keywords: NPK fertilizer, population density, maize variety, yield improvement

Assessment of genetic diversity of selected cowpea landraces from Nigeria based on simple sequence repeat markers

Understanding the genetic diversity of cowpea (Vigna unguiculata L. Walp.) landraces is useful for effective characterization and ex-situ conservation of germplasm. The analysis of genetic diversity of eighteen cowpea landraces collected from five agro-ecological zones in Nigeria was reported in this study. Five individuals per landrace were genotyped with six polymorphic microsatellite markers. Three to 5 alleles with a mean of 3.833 were detected. Mean Polymorphic information content (PIC) and observed heterozygosity of the markers were 0.5721 and 0.2433, respectively. Analysis of Molecular Variance (AMOVA) showed that variation due to agroecological zone constituted 24%, while variations among and within landraces as well as within individuals constituted 25%, 17% and 33%, respectively. Landraces collected from the humid rainforest zone showed high within landrace diversity and were not significantly different (P ≥ 0.001) from other landraces collected from the same zone. Landraces from the savannah zones showed low within landrace diversity and homozygous across all loci. Consequently, among landrace diversity was higher in the savannah zone with landraces collected from guinea savannah been the most diverse, followed by landraces from the derived savannah and Sudan savannah. Mantel test showed positive and significant correlation (r= 0.377, p= 0.01) between genetic and geographical distance of landrace collections. The findings are important for up-to-date characterizations of cowpea germplasm in Nigeria for improved breeding programs.&#x0D; Keywords: Genetic diversity, cowpea, Alleles, Polymorphic information content, AMOVA,