Spatial and temporal drought analysis in the north central region of Nigeria

This study examined the occurrence of drought in north central Nigeria. Problems related to drought includes: unpredictable commencement and end time of rainfall season, seasonal rainfall fluctuations, long period of no rainfall. Monthly rainfall data was obtained from the Nigeria Metrological Agency (NIMET) Lagos. This covers up to 51 years for seven different metrological stations namely: Lafia, Ilorin, Markurdi, Jos, Lokoja, and Minna and Abuja. Standardized Precipitation Index (SPI) was adopted for this study. SPI approach requires a transformation to the initial distribution of rainfall to achieve a normalized distribution. Drought analysis indicates 1980s as the decade with worst drought effect as drought incidences were observed in Jos, Minna, Ilorin and Markurdi stations and 1983 as the only year in which drought occurred simultaneously across four different stations.Keywords: Drought Risk, Standardized Precipitation Index (SPI), Metrological Drought, Time Scal

Estimating a municipal water supply reliability

The availability and adequacy of water in a river basin determine the design of water resources projects such as water supply. There is a further need to regularly appraise availability of such resource for municipality at a distant future to help in articulating contingent plan to handle its vulnerability. This paper attempts to empirically determine the reliability of water resource for a municipal water supply. An approach was first developed to estimate municipality water demand that lack socioeconometric data using a purpose-specific model. Hydrological assessment of river Oyun basin was carried out using Markov model and sequent peak analysis to determine the reliability extent for the future demand need. The two models were then applied to Offa municipality in Kwara state, Nigeria. The finding revealed the reliability and adequacy of the resource up till year 2020. The need to start exploring a well-coordinated conjunctive use of resources is recommended. The study can serve as an organized baseline for future work that will consider physiographic characteristics of the basin and climatic dynamics. The findings can be a vital input into the demand management process for long-term sustainable water supply of the town and by extension to urban township with similar characteristic

Biological effects of African yam bean lectins on the cowpea coreid bug, Clavigralla tomentosicollis (Stal)

The biological effects of affinity purified seed lectin from African yam bean, Sphenostylis stenocarpa (Harms), were tested on Clavigralla tomentosicollis (Stål) in an artificial seed system. S. stenocarpa was extracted from two African yam bean accessions: Enugu 95-3 and Enugu 98-2. Lectins from both accessions were highly toxic to the insect at 1.0% dry weight. For nymphs feeding on Enugu 95-3 and Enugu 98-2, survival ranged from 16.0 to 24.0% and 4.0 to 16.0% at 1.0 and 2.0% dry weight dietary lectin levels, respectively. From 4.0 to 8.0% dry weight of both lectins, no nymph survived up to 6 d after infestation. At 1.0% dry weights of Enugu 95-3 and Enugu 98-2 lectins, there was a significant delay in total developmental time (5.35 and 5.18 d), reduced survival (24.0% and 16.0%), and reduced growth (0.15 ± 0.02 and 0.14 ± 0.01) and resistance (61.85 ± 9.78 and 57.79 ± 3.80) indices, respectively. S. stenocarpa from Enugu 98-2 was the most toxic, with an LD50 of 0.43%, compared with an LD50 of 0.65% for S. stenocarpa from Enugu 95-3. The results of this investigation indicate that there exists in C. tomentosicollis physiological systems vulnerable to African yam bean lectins

Insecticidal activities of the African yam bean seed lectin on the development of the cowpea beetle and the pod sucking bug

The cowpea beetle, Callosobruchus maculatus, and pod-sucking bug, Clavigralla tomentosicollis, are two of the major insect pests of cowpea in Africa. A lectin was purified from the seeds of the African yam bean (AYB), Sphenostylis stenocarpa, by affinity chromatography on Galactosc-Sepharose 4B. The purified AYB lectin (AYBL) was tested on the two insect pests of cowpea. When C. maculatus larvae were fed on artificial cowpea seed containing 0.2, 2, and 5% (w/w) of dietary lectin, larval mortality ranged from 30 to 88% and delay in number of days to first emer gence from 4-13 days. When AYBL was tested on C. tomentosicollis, nymphal mortalities ranged from 76 to 81% at 1% and 87 to 94% at 2%. From 4 to 8%, no nymph survived up to six days after infestation. The results of these insect bioassays provided a scientific basis for isolating a lectin gene from AYB for the transformation of cowpea

Isolation and partial characterisation of galactosespecific lectins from African yam beans, Sphenostylis stenocarpa Harms

A new galactose-specific lectin was isolated from African yam bean (Sphenostyles stenocarpa Harms) by affinity chromatography on galactose-Sepharose 4B. SDS–PAGE analysis resulted in four polypeptide bands of approximately 27, 29, 32 and 34 kDa, respectively. Based on the analysis of carbohydrate content and native PAGE, it is likely that the Sphenostyles lectin is a tetrameric glycoprotein with Mr of approximately 122 kDa. N-terminal protein sequencing of purified lectins from four different Sphenostyles accessions shows that the four polypeptides have largely identical amino acid sequences. The sequences contain the conserved consensus sequence F-F–LILG characteristic of legume lectins, as well as Phaseolus vulgaris proteins in the arcelin-α-amylase inhibitor gene family. The lectin agglutinates both rabbit and human erythrocytes, but with a preference for blood types A and O. Using Western blotting, the lectin was shown to accumulate rapidly during seed development, but levels dropped slightly as seeds attained maturity. This is the first time a lectin has been purified from the genus Sphenostyles. The new lectin was assigned the abbreviation LECp.SphSte.se.Hga1