Numerical Analysis of Variation Among Nigerian Accessions of 'Egusi' Melon (Citrullus lanatus (Thunb.) Matsum & Nakai)

Abstract: Fourteen quantitative characters were measured in 20 accessions of 'egusi' melon. Principal Component Analysis (PCA) and Single Linkage Cluster Analysis (SLCA) were employed to analyse the variation pattern in these accessions. The first three principal components accounted for 76.33% and 78.70% of the total variation in the early and late seasons respectively. SLCA summarized the relationship among the accessions at various levels of similarity into a dendogram while the accessions were sorted into six distinct groups. The implication of these results for 'egusi' melon breeding is discussed. INTRODUCTION In cross pollinated crops such as 'egusi' melon, germplasm often exist in the form of heterozygous genotypes which could be improved through intraspecific hybridization and selection. Development of improved varieties of crop plant necessarily involves the incorporation of specific gene complexes governing desired traits. Plant breeders firstly identify traits in plant species that makes them suitable for utilization by man, then search out new genes for the desired traits in new cultivars (or strains) using traditional techniques or biotechnology. They then finally access the performance of the new cultivars before releasing them as registered cultivars to be grown widely by farmers and enjoyed by consumers. It is important to classify the range of variability among accessions to facilitate the maintenance and further acquisition of germplasm resources. Thus, the wealth of any germplasm collection is measured in terms of the genetic variability of the crop species it contains. Many techniques have been employed by researchers to determine the extent of variability in a germplasm collection. The Principal component analysis (PCA) has been used to measure genetic divergence among genotypes. This method which is a common ordination technique reduces the dimension of multivariate data by removing inter-correlations among attribute-variables (characters on which units are to be compared), and enables multidimensional relationships to be plotted on two or three principal axe

Discriminating Nigerian ‘Egusi’ melon accessions using agro-morphological and molecular techniques

‘Egusi’ melon is an important vegetable crop in the tropics and subtropics that is rich in protein, oils and vitamins. Agro-morphological traits, sequence related amplified polymorphism (SRAP) and simple sequence repeats (SSRs) were used to evaluate 50 accessions of ‘egusi’ melon collected from various parts of the country. The FASTCLUS procedure grouped the accessions into ten distinct groups based on agro-morphological data, with accessions NG/TO/APR/09/029 and A23 characterized by long vines and high seed weight per fruit. A total of 197 bands were scored from 26 SRAP primers, while 49 bands were scored for 25 SSR primers. UPGMA cluster analysis based on dice genetic similarity revealed five and six distinct groups for the SRAP and SSR primers, respectively. A higher level of polymorphism was observed for the SSR primers (93.60%) as compared with the SRAP primers (64.65%), though the discriminating power of the SSR primer (2.28) was lower than that of the SRAP primer (3.71). The relatively higher frequency of SSR polymorphism should be helpful in phylogenetic analysis to better understand these relationships in the melon accessions.Key words: ‘Egusi’ melon, Agro-morphological traits, SRAP, SSR, Discriminatio

Posttraumatic Stress Syndromes among Victims of the Ife/Modakeke Crisis

The main purpose of this study was to estimate the incidence of posttraumatic stress disorder (PTSD) among the victims of the March 2000 Ile-Ife/Modakeke crisis. It also examines most of the risk factors (such as degree of exposure, age and gender) that predispose the victims to PTSD.  An initial sample of 456 male and female respondents from both communities field in a simple questionnaire that assessed the degree of exposure to trauma and self-reported PTSD symptoms.  The results indicate that a substantial proportion (19%) of the initial sample reported symptoms of such magnitude as could be diagnosed as PTSD.  Age and the degree of exposure to trauma were fund to be risks factors for PSTD in the population. The implications of these results for therapy, the provision of relief to traumatized populations and future research are highlighted and discussed. Keywords: Posttraumatic stress syndromes, victims, Ife/Modakeke crisi

Germination and In Vitro regeneration response of local Nigerian tomato cultivar using different explant sources

In vitro regeneration of plants is an important tool in both basic and applied studies as well as commercial applications. It can be of use in overcoming the constraints of tomato production. Assessment of seed sterilization procedures and in vitro regeneration of tomato cultivar was attempted using different explant sources. Seed sterilization procedures with and without ethanol treatment and varying duration of application were used while explants were cultured on Murashige and Skoog (MS) medium only and MS media with varying concentrations of cytokinins and fixed concentration of auxin as Regeneration media (RM). Seeds sterilized with 10% (v/v) solution of sodium hypochlorite for 10 min with two to three drops of non-ionic surfactant (Tween 20) added without ethanol treatment and repeated for 5 min gave the highest germination percentage of 57.33% and percentage contamination of 11.11% compared to seeds sterilized with other disinfection procedures. MS media supplemented with 2 mg/l Kinetin and 0.1 mg/l NAA produced average shoot initiation values of 1.71, 1.57 and 1.57 and average root initiation values of 0.57, 0.00 and 2.85 for cotyledon, hypocotyl and leaf explants respectively. The study showed that the tomato cultivar could be amenable for crop improvement and micro propagation purposes.Key words: Seed sterilization, In vitro regeneration, explant, cultivar, organogenesis