Agro-ecological Zone Of Nigeria Research Articles

Incidence and health risk assessment of hydrogen cyanide and multi-mycotoxins in Nigerian garri

Garri is a granular, starchy food prepared by the fermentation of mashed cassava. Hydrogen cyanide (HCN) and mycotoxins are contaminants in certain foods at different points along the food value chain. The incidence and contamination levels of HCN and multi-mycotoxins in garri from five agroecological zones of Nigeria were determined using a spectrophotometric method and ultra-high-performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS), respectively. The health risk associated with the consumption of contaminated garri was assessed. The health risk assessment model was used to calculate the dietary exposure of humans to the mycotoxins in garri. This was done by estimating the daily intake (EDI), the percentage tolerable daily intake (%TDI), the annual hepatocellular carcinoma (HCC) cases attributable to exposure to aflatoxins (AFs) in garri, as well as the HCC risk. The average intake of garri was estimated at 0.303 kg/day for a Nigerian adult. The incidence of HCN was 98.3% (0.056–2.463 mg/kg), and fermentation reduced the HCN level in garri more than other processing steps. The twenty-one mycotoxins identified and quantified were all within maximum levels, as applicable to those that are regulated by the EU. The %TDI for the other mycotoxins, with the exception of AFs, showed no alarming health risk with garri consumption. Annual HCC cases resulting from AF in garri were estimated at 10–60 cases for HBsAg + ve individuals and 4–23 cases for HBsAg − ve individuals based on 8.1% hepatitis B virus (HBV) incidence. Results further revealed no interdependence between HCN levels and mycotoxin content. This work suggests an unlikely chance of acute toxicity from HCN and major mycotoxins from a garri-based diet in Nigeria. Hence, it is recommended that concerned regulatory bodies maintain the existing permissible limits for HCN in Garri.

Evaluation of Sweet Potato (Ipomoea batatas) for Early Blast Disease (Alternaria solani)

Aims: Early blight disease (Alternaria solani) is one of the main biotic factors limiting sweet potato production in the tropics. A multi-locational research was carried out to screen and identified sweet potato accessions that are resistant to the disease.
 Methodology: 21 sweet potato accessions were collected from different agro-ecological zones of Nigeria and screen against Alternaria solani by artificial inoculation of the pathogen in three diverse agro-ecological conditions. The accessions were named against their place of condition. The research were laid out in a Randomized Complete Block Design (RCBD) with three replications. Data were collected on days to 50% flowering, fresh root weight per plant, number of root per plant, number of main branches per plant, and above ground fresh biomass yield per plant at 15 weeks after planting (WAP). Disease scoring was done using rating scale 0f 0-9 and analyzed with IRRI STAR software.
 Results: The result revealed that there are variations in the 21 accessions studied. Offa performed best across the three environments followed by Umudike while Ado-Ekiti had the least performance in term of root yield. The screening shows that none of the 21 accessions is highly resistant. Four of the accessions were resistant, six accessions were moderately resistant, four accessions were susceptible, and three accessions were moderately susceptible while 4 accessions were highly susceptible to the pathogen.
 Conclusion: The findings concluded that the resistant accessions that gave high number roots could be used as a gene pool for Alternaria solani resistance breeding for cultivar improvement. The use of the identified resistant accessions with high root yield by farmers is encouraged pending the time commercial Alternaria solani resistant cultivars will be readily available and accessible.

Molecular Characterization of Fungal Isolates of Locally Processed Rice from Five Agro-Ecological Zones of Nigeria

The purpose of this study was to characterize fungal isolates contaminating locally processed rice in Nigeria and to assess the genetic similarity in the fungi isolates. Fungal species were characterized by amplification of a segment of the β-tubulin gene using Bt2aF (5’-GGTAACCAAATCGGTGCTGCTTTC-3’) and Bt2bR (5’ACCCTCAGTGT GT GACCCTTGGC-3’) primers and phylogenetic relationship established using the Maximum Likelihood method. Amplification of between 450 and 550bp of the β-tubulin region of the genomic DNA of the fungal isolates was obtained from thirty-eight samples (89%). Members of Aspergillus section flavi and section nigri groups were differentiated as A. flavus, A. parasiticus, A. tubigensis, A. sydowii and A. niger respectively. Molecular method identified Paecilomycesformosus with 99% similarity index while all the morphologically identified Penicillium species were identified to genus level as P. formosus, P. steckii and P. citrinum with a percentage similarity ranging from 95%-100%. Collectotrichum fruticola and Talaromyces flavus from SGS and NGS zone respectively were documented for the first time in the locally processed rice with 100% and 89% similarity index respectively. All the Aspergillus species were closely related to one another and narrowly diverged from the Penicillium species. Aspergilla and Penicillia were the predominant genera identified and the isolates were genetically similar irrespective of their agroecological zones.

Assessment of Weathering Intensity and Pedogenesis of Lithosequence Located in Two Agroecological Zones of Nigeria

Elemental oxides can help to identify processes of soil formation and the degree of soil development. This study assessed soil development and weathering intensity in soils developed on schist and older granite in upland tropical rain forest and southern guinea savanna agro ecological zones of Nigeria. Soil profile samples were collected in each of the study locations. In the laboratory, total elemental oxides was determined using the energy dispersing X-ray Fluorescence (EDXRF) XRF SPEC (Minipal 4). The relative intensity of weathering of total elemental oxides was determined by choosing titanium as the suitable indexing element and the relative gain or loss of element was estimated using relative retained element (Ro) equation. Result obtained, revealed that SiO2 was the most abundant in the soils. Distribution of Al2O3 and CaO showed the direction of the pedogenic age. Older granite soil had higher values of Al2O3 and lower values of CaO. There was negative relationship of SiO2 with Al2O3 and Fe2O3. The trace elemental oxides were less than 1% and zirconium oxide was the most retained oxide in the soils. Soil which developed on schist retained more of the trace elements than soil on older granite. There was evidence of alitization, ferritization and desillication in the soils. Parent materials contributed to loss and gain of trace elemental oxides. Older granite soil was more weathered and pedologically older than schist derived soils.

Agricultural insurance as a climate risk adaptation strategy in developing countries: a case of Nigeria

ABSTRACT Despite the potential benefits of agricultural insurance in helping farmers adapt to climate risks, its uptake among smallholder farmers remains limited. This study analyses the drivers of awareness and adoption of agricultural insurance in Nigeria to better understand the adoption process. 1,080 farming households were surveyed across six agro-ecological zones in Nigeria, covering areas with different socio-economic characteristics of farmers and levels of climate risk. Data were collected through face-to-face interviews between October 2020 and February 2021. The results show that more than half of the farmers were unaware of agricultural insurance. Logit regression results show that education, herd size, access to a bank, weather information, and flood experience positively influence awareness and adoption of agricultural insurance. In addition to low awareness, the main barriers to adoption are lack of knowledge about the effectiveness of insurance, difficulty in affording insurance, and farmers’ low level of trust in insurance providers. Late payment of claims and inadequate compensation were the main challenges faced by adopters of agricultural insurance. Raising awareness and helping farmers to assess the effectiveness of agricultural insurance, as well as developing a supportive institutional environment, would help to build a well-functioning insurance market. Key policy insights To increase the uptake of agricultural insurance, it is first necessary to raise awareness among farmers. Government agencies should consider monitoring and sanctioning insurance agencies and companies that fail to comply with contractual agreements to promote and ensure prompt payment of due compensation; to increase transparency of insurance providers’ performance; and to increase confidence in insurance providers. We recommend using different premium payment methods, adjusting land policies, improving access to weather information, and increasing access to bank credit for smallholder farmers to increase farmers’ motivation to use insurance.

Genetic Diversity Assessment of Winged Bean [Psophocarpus tetragonolobus (L.) DC.] Accessions Using Agronomic and Seed Morphometric Traits

Winged bean [Psophocarpus tetragonolobus (L.) DC.] is an underutilized legume with the potential to contribute to nutrition and food security globally, particularly in sub-Saharan Africa (SSA). However, more attention needs to be paid to exploiting its full potential due to a lack of adequate knowledge of the existing genetic diversity in the available winged bean germplasm. To bridge this gap, thirty accessions of winged beans sourced from the Gene Bank of the International Institute of Tropical Agriculture (IITA), Ibadan, were evaluated for seed morphometric and selected agro-morphological traits at three agro-ecological zones in Nigeria. The data obtained were subjected to analysis of variance (ANOVA), principal component (PC) analysis, cluster analysis, and correlation analysis. Significant differences (p < 0.05) were observed among the accessions for all measured traits. The first two PCs accounted for 88.2% of the variation observed among the accessions for all measured traits. Accessions were grouped into three clusters based on the agro-morphological traits and three clusters under the multi-spectral imaging (MSI) system. TPt-31 had the highest seed yield per plant, pod weight per plant, and early maturity, while TPt-7 had an extended flowering and maturity period, the highest number of pods per peduncle and pods per plant, as well as the lowest seed yield. These accessions could be a good resource for future winged bean improvement programs. The result also confirmed that the MSI system is an invaluable tool for discriminating among accessions of the same crop species. The findings of this study provide insight into the genetic diversity of winged bean germplasm, which could contribute to improving its yield and quality in SSA and globally.

Soil properties affecting soil organic carbon stock of different land use types in two agro-ecological zones of Nigeria

Soil organic carbon (SOC) stock is the carbon proportion that is of biological origin stored with respect to soil depth. It is more prone to loss than soil inorganic carbon. High sequestration of SOC in soil is germane to the improvement of soil quality and mitigating impact of climate change. Thus, this study was carried out to evaluate soil properties affecting SOC stock in the two agro-ecological zones, namely Upland Rainforest (Ado-Ekiti) and southern Guinea Savanna (Kabba) agro-ecological zones of Nigeria, with respect to three selected land use types; arable, oil palm and wetland. Random collection of soil samples was carried out at four varying depths (0-15, 15-30, 30-45, and 45-60 cm) for evaluation of soil properties. The SOC stock regression models for the two agro-ecological zones showed that land use, SOC, pH, SOM (soil organic matter), Ex-K, Ex-Ca, Ex-Mg (exchangeable potassium, calcium, magnesium, respectively), BD (bulk density), and gravel content would predict variation in SOC stock in the two agro-ecological zones with coefficient of determination (R2) values of 0.952 and 0.996 for Kabba and Ado-Ekiti respectively. Principal component analysis identified that in the soil of the southern Guinea Savanna agro-ecological zone, SOC, CEC, EA, Ex-Na, land use, clay content, and soil depth with Eigenvalues > 1 explained 80.58% of sample variance while in the soil of the Upland Rainforest agro-ecological zone, Ex-Ca, SOC, Ex-Na, EA, sand and silt contents with Eigenvalues > 1 explained 78.81% of sample variance as potential determinants of SOC stock.

Effects of climate change and drought attributes in Nigeria based on RCP 8.5 climate scenario

Historical observatory and future simulated datasets based on representative concentration pathway (RCP) 8.5 scenario covering from 1951 to 2100 were analysed. Four well accepted drought indices: the standardized precipitation index (SPI), standardized runoff index (SRI), reconnaissance drought index (RDI) and standardized precipitation and evapotranspiration index (SPEI) were used in drought characterization. The ensemble of the seven GCMs using RCA-4 captured some pragmatic features of the climatology of Nigeria in the historical period. The correlations between SRI and SPEI/SPI are significant. The major peaks can be divided into three drought cycles with 1–2, 2–4 and 8–16 periods (years). On a general note, there is a projection of an increase in both the frequency and intensity of drought in the five classified agroecological zones in Nigeria. Considering the output of drought characteristics as measured by SPI, future climates were predicted to be more wet when compared to the historical period as indicated in the study. In contrast, SPEI and RDI forecasted dryer climates. The prediction of SPEI and RDI must have been predicated on the influence of increasing temperature due to global warming as captured by RCP 8.5, which would in turn affect the rate of evapotranspiration. In view of drought analysis using the RCP 8.5 scenario, the frequency of severe/extreme drought will likely become more intense especially towards the end of the 21st century.

A Review of Sustainable Agroforestry Practices as Climate Change Adaption and Mitigation Strategy in Nigeria

Agroforestry is one of the most conspicuous land use systems across landscapes and agroecological zones in Nigeria. With food shortages and increased threats of climate change, interest in agroforestry is gathering for its potential to address various on-farm adaptation needs, and fulfill many roles in mitigation pathways. Agroforestry provides assets and income from carbon, wood energy, improved soil fertility and enhancement of local climate conditions; it provides ecosystem services and reduces human impacts on natural forests. Most of these benefits have direct benefits for local adaptation while contributing to global efforts to control atmospheric greenhouse gas concentrations. This paper presents recent findings on how agroforestry as a sustainable practice helps to achieve both mitigation and adaptation objectives while remaining relevant to the livelihoods of the poor smallholder farmers in Nigeria. Keywords: Review, sustainable, Mitigation, adaptation, climate change, strategy, Nigeria DOI: 10.7176/JEES/12-12-01 Publication date: December 31 st 2022

Neuroecotoxicology: Effects of environmental heavy metal exposure on the brain of African giant rats and the contribution of vanadium to the neuropathology.

Increased exploitation of minerals has led to pollution of confined environments as documented in Nigeria Niger Delta. Information on the effects on brain of such exposure is limited. Due to its exploratory activities, the African giant rat (Cricetomys gambianus) (AGR) provides a unique model for neuroecotoxicological research to determine levels of animal and human exposure to different pollutants. This study aims to unravel neuropathological features of AGR sampled from three agro-ecological zones of Nigeria. Fifteen AGR were sampled according to previously determined data on heavy metal exposure: high vanadium, high lead, and low metals. Eighteen AGR were collected from low metal zone and divided into two groups. Control group received vehicle while SMV exposed group received 3mg/kg sodium metavanadate (SMV) intraperitoneally for 14days. Brain immunohistochemical analyses were conducted, and ultrastructural changes were studied in experimentally exposed group. Results showed significant loss of tyrosin hydroxylase, parvalbumin, orexin-A and melanin concentration hormone containing neuronal populations in brains obtained from high vanadium and high lead zones and in experimentally intoxicated SMV groups. Similarly, significant decrease numbers of dendritic arborations; extracellular matrix density, perineuronal nets; astrocytes and microglia activations are documented in same groups. Ultrastructural studies revealed mass denudation, cilia loss, disintegration of ependymal layer and intense destructions of myelin sheaths in SMV exposed group. These are the first "neuroecotoxicological" findings in distinct neuronal cells. The implications of these findings are highly relevant for human population living in these areas, not only in Nigeria but also in similarly polluted areas elsewhere in the world.

Parsimonious genotype by environment interaction covariance models for cassava (Manihot esculenta).

The assessment of cassava clones across multiple environments is often carried out at the uniform yield trial, a late evaluation stage, before variety release. This is to assess the differential response of the varieties across the testing environments, a phenomenon referred to as genotype-by-environment interaction (GEI). This phenomenon is considered a critical challenge confronted by plant breeders in developing crop varieties. This study used the data from variety trials established as randomized complete block design (RCBD) in three replicates across 11 locations in different agro-ecological zones in Nigeria over four cropping seasons (2016–2017, 2017–2018, 2018–2019, and 2019–2020). We evaluated a total of 96 varieties, including five checks, across 48 trials. We exploited the intricate pattern of GEI by fitting variance–covariance structure models on fresh root yield. The goodness-of-fit statistics revealed that the factor analytic model of order 3 (FA3) is the most parsimonious model based on Akaike Information Criterion (AIC). The three-factor loadings from the FA3 model explained, on average across the 27 environments, 53.5% [FA (1)], 14.0% [FA (2)], and 11.5% [FA (3)] of the genetic effect, and altogether accounted for 79.0% of total genetic variability. The association of factor loadings with weather covariates using partial least squares regression (PLSR) revealed that minimum temperature, precipitation and relative humidity are weather conditions influencing the genotypic response across the testing environments in the southern region and maximum temperature, wind speed, and temperature range for those in the northern region of Nigeria. We conclude that the FA3 model identified the common latent factors to dissect and account for complex interaction in multi-environment field trials, and the PLSR is an effective approach for describing GEI variability in the context of multi-environment trials where external environmental covariables are included in modeling.

EFFECT OF TRANSPLANTING DATES ON GROWTH AND YIELD COMPONENTS OF PEPPER (Capsicum Spp) IN BADEGGI, NIGERIA

Field experiment were conducted to determine the effects of transplanting date on growth and yield of pepper (Capsicum Spp) varieties at the irrigated Research farm of the National Cereal Research InstituteBadeggi, Niger State, Nigeria in 2018 and 2019 rainy seasons were assessed. The experiment was a 5 x 4 factorial laid out in a randomized complete block design with three replication and consisted of five pepper varieties (Tabasco, Bell pepper, Rocoto, Hottest pepper and South Africa pepper) and four transplanting dates (3rd June, 3rd July, 3rd August, and 3rd September). Result indicated significant differences (P<0.05) among the pepper varieties and transplanting dates. Rocoto variety was the tallest variety in both years while Bell pepper was the shortest. Bell pepper had the largest leaf area (49.88, 41.90 and 41.19cm2 in 2018 and 46.78, 46.34 and 40.99cm2 in 2019 at 6, 9, 12 weeks after transplanting WAT respectively). Fresh and dry fruit yields from Rocoto variety superseded other variety by 21-82% and 22-85% in 2018 and 27-83% and 35-87% in 2019. Pepper transplanted in July and significantly (P<0.05) higher number of leaves per plant, larger leaf area, number of branches per plant and taller plants than other transplanting dates. Also, transplanting dates had significant effects (P<0.05) on pepper phonological and yield components. 3rd September transplanting attained 50% of flowering, fruiting and ripening earlier than other dates in both years. July transplanting date had the highest fresh (13.40 and 13.87t/ha-1) and dry (9.88 and 9.15 tha-1) fruit yields in both years. Fresh and dry fruit yields from plants transplanted in 3rd July susperseded other dates in both years. Findings from this experiment show that transplanting Rocoto variety in July would guarantee high productivity of pepper in Badeggi, Southern Guinea Savanna agro-ecological zone of Nigeria.

Assessment of vegetation cover dynamics in the agro-ecological Zones of Nigeria

The drastic vegetation loss of about 22% in 12 years across agro-ecological zones (AEZs) in Nigeria, which can be attributed to the impact of climate and anthropogenic activities on vegetation dynamics within the context of socio-economics, calls for concern. In this study, remotely sensed data from the European Space Agency Land Use/Land Cover dataset, TAMSAT rainfall data, and MODIS NDVI dataset were used to examine changes in vegetation dynamics and monitor vegetation health in the AEZs based on the Normalised Difference Vegetation Index (NDVI). The study showed that vegetation cover has been decreasing tremendously at an alarming rate in most of the zones, while different drivers (change agents) have been responsible for the losses. The analysis shows that, between 2003 and 2018, the forestland cover gained 9,768.88 km2 and lost 40,891.6 km2, with a total net decrease of 31,122.73 km2. Contribution to the net change in forestland is usually converted to wetland, urban, cropland and grassland, across the varied ecosystem. The need for up to-date and accurate land-cover information is key to developing an appropriate mitigation strategy within the context of socio-economic sustainability across AEZs in Nigeria.

Assessing the Spatial Variability of Soil Properties to Delineate Nutrient Management Zones in Smallholder Maize-Based System of Nigeria

Spatially explicit information on soil variability is relevant for agronomic decisions; however, such information is limited in the northern Guinea savanna (NGS) agroecological zone of Nigeria. This study was conducted to delineate soil nutrient management zones (MZs), based on spatial variability of soils in the smallholder maize-based farming system within the NGS. Two hundred and eighty-nine soil samples were analyzed for some physical and chemical properties. Principal component analysis (PCA) was used to aggregate the soil properties into four principal components, which accounted for about 60% of the variation in the data, and spatial variability was assessed with a semivariogram. The ordinary kriging technique was used to predict soil properties at unsampled locations, while weighted overlay analysis was conducted to delineate nutrient management zones. Results showed that total nitrogen (0.06%), available phosphorus (5.6 mg kg−1), organic carbon (0.66%), and effective cation exchange capacity (5.6 cmol(+) kg−1) are below optimal requirement for maize production. Four MZs were identifiable in the region with the highest fertility (MZ3 and MZ4) associated with the northern area but covering a relatively small part (9.1%). The differences observed in soil properties among the MZs suggest that each zone requires different agronomic management, especially in relation to fertilizer application.

Effect of nitrogen and weeding regimes on yield and yield components of maize (Zea mays L.) in the derived guinea savanna Agro-ecological zone of Nigeria

In the 2017 and 2018 wet seasons, field trials were conducted at the Teaching and Research Farm of the Faculty of Agriculture, Kogi State University, Anyigba to determine the effect of nitrogen and weeding regime (period of weed interference) on the yield and yield components of maize. The experimental design used was a split-plot in a randomized complete block design replicated three times. The main plot was assigned to four different levels of nitrogen 0, 40, 80 and 120 kg N/ha while the sub-plot was assigned to different frequencies or regimes of weed control. The results obtained from the study revealed that the application of 120 kg N/ha produced the highest cob weight, 100-seed weight and grain yield per hectare in both years. The study also showed that all the rates of nitrogen application resulted into increased grain yield in comparison to where there was no nitrogen application. Maize plant kept weed-free for 9 and 12 weeks after planting (WAP) and those weed infested for 3 WAP produced cob dry weight, 100-seed weight and grain yield (kg/ha) comparable to those kept weed-free throughout. From the two-year study conducted, it was found out that keeping the field weed-free for only 3WAP did not provide a satisfactory weed control situation for optimum crop performance owing to imminent re-infestation. Conversely, plants weed infested for 3WAP could ward off whatever damage that might have been inflicted initially through subsequent re-growth which could translate into impressive yield as observed in this study.

Contamination of Locally Compounded Poultry Feeds and Ingredients by Fungi of the Genus Penicillium and Aspergillus within Three Agro-Ecological Zones of Nigeria

Introduction: Fungi generally are field and storage contaminants of poultry feeds and feed ingredients, the fungal contamination of poultry feeds affects the quality negatively by causing caking, reducing quality and quantity of nutrients, and eventually producing secondary metabolites known as mycotoxins in these products when the environment is conducive. This study was carried out to isolate Aspergillus and Penicillium species from locally compounded poultry feed and feed ingredients that arrived at poultry farms within 30 days.
 Method: A total of 52 samples of feed (n=13) and feed ingredients (n=39) were collected across 3 agroecological zones (involving 6 states) of Nigeria. Different mycological media was used for isolation, by deploying the pour plate method. The identity of Aspergilli and Penicilli isolates was characterized using macroscopic and microscopic observed features.
 Results: Hundred per cent of the feed samples were contaminated with Aspergillus species while 63% were contaminated with Penicillium species. Nine species of Aspergillus and five species of Penicillium were detected in the feed and feed ingredients. The highest occurring fungal genus was Aspergillus, specifically, Aspergillus niger and Aspergillus flavus species were the highest occurring species. Penicillium glabrum was the most predominant Penicillium species isolated from the compounded poultry feed and feed ingredient samples.
 Conclusion: All the feed samples (100%) were contaminated with several species of Aspergillus and Penicillium. The feed ingredients had 100% contamination except for the bone meal samples 78% contamination.

Morphological and biochemical characterization of strains of Xanthomonas axonopodis pv. vignicola isolated from cowpea grown in three agroecological zones in Nigeria

Cowpea bacterial blight (Xanthomonas axonopodis pv vignicola) is a devastating disease of cowpea in Nigeria. Accurate identification is the first step for an effective management option. Thus, X. axonopodis pv. vignicola isolated from cowpea (Vigna unguinculata (L.) Walp) grown in different Agro-ecological zones in Nigeria were characterized using morphological characteristics, biochemical and antibiotic sensitivity tests. Pot experiments were conducted on two susceptible lines of cowpea (IT90k – 76) and (IT84s – 2246 – 4) in the screen house. In vivo infectivity studies were carried out to determine the effect of each of theX. axonopodis pv. vignicola isolate groups on the cowpea. All isolates from each of the agroecological zones were classified into Group 1 (light yellow) and Group 2 (brownish yellow) based on their morphological presentation on nutrient agar medium. Results from four of the biochemical test showed differences between the two morphologically different groups. Group 2 isolates showed a large zone of inhibition to a Lincomycin hydrochloride while isolates from Group 1 were not affected by the action of the same antibiotic. Blight symptom was only observed when the two types of isolates were combined and inoculated simultaneously. This study showed that there are two morpho-types of X. axonopodis pv. vignicola and their synergetic infectivity results in blight symptoms expression in cowpea.

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.