No abstract

Farmers have long considered urban agriculture as a panacea to urban food insecurity. However, growing food in cities is faced with many challenges like food contamination. Past studies on leafy vegetables focused on vegetables cultivated in urban centres. However, this paper aimed to determine and compare the level of heavy metals concentrations in soil and leafy vegetables in Urban Expressway Farms (UEF) and Peri-urban Road Farms (PRF) in Lagos, Nigeria. These two locations were purposefully selected. Soil Auger was used to drill holes to the required soil depth to collect soil samples. Sample of Amaranthus hybridus, Celosia argentea and Corchorus olitorius were collected using “envelope” principle. Pb, Cd and Mn residues in the samples were digested and determined using Atomic Absorption Spectrophotometer. The collected data were analysed using mean, standard deviation and Analysis of Variance. The mean pH value for UEF soil is 6.5 while PRF soil is 6.6. The highest Pb (0.93±0.06) was recorded in Celosia argentea at UEF. The highest mean concentration of Cd (0.51±0.11) was recorded in Amaranthus hybridus at UEF. The highest concentration for Mn was recorded in Amaranthus hybridus (0.98±0.02) at UEF. The concentrations of Pb in Celosia argentea at UEF 5 m from the expressway and Cd concentration in Amaranthus hybridus at 10 m from expressway were above the WHO/FAO permissible levels in vegetables. Level of heavy metal residue observed in soil and vegetables under this study were mostly influenced by the location of the farm-environment and not mainly the vegetable type.  The relative concentrations of Pb and Cd in all the three leafy vegetables raise some serious environmental concerns and need to be monitored regularly to prevent consumption of contaminated leafy vegetables. Farmers are encouraged to cultivate in fields far away from expressway.

Twenty two groundnut genotypes collected from International Crops Research Institute for Semi Arid Tropics (ICRISAT) and local sources (Samaru, UNILORIN and UNAAB) were cultivated in Lagos (60º 36'N, 30º 34'E) and Abeokuta (70º 10'N, 30º 20'E) during 2010 planting seasons, to determine the genetic variability and performance of the genotypes. Data collected on ten (10) characters and yield was subjected to multivariate analysis to determine genetic divergence among the genotypes. Number of pods per plant showed significant positive correlation with yield per plant in both environments also had the largest direct positive effect on yield per plant (0.66, 0.70). Days to maturity showed the largest direct negative effect of-0.33 and-0.36 in Lagos 2003 and Abeokuta 2004 respectively. Heritability estimates ranged from 62.34% to 90.67 and 24.75 to 89.46 for number of branches per plant at flowering and days to maturity in (E1) Lagos and (E2) Abeokuta, respectively. The mean squares of the combined analysis of variance revealed significant genotypes and Genotype x Environment interactions on yield per plant.

No abstract

This study aimed at investigating genetic divergence in twenty genotypes of fluted pumpkin (Telfairia occidentalis) and determines the characters responsible for the variation. The twenty genotypes were collected from different locations within southern Nigeria (Anambra, Enugu, Lagos, Ondo and Ogun). The experiment was carried out at the Lagos State University Botanical Garden using a Randomized Block Design (RBD) with three replications. The collected data were subjected to Principal Component Analysis (PCA) and Factor Analysis to evaluate the patterns of variation in these genotypes. Two out of the twenty four principal components had eigen values greater than 2.0. The first five principal component jointly accounted for 88.61% of the total variation among the genotypes. Twenty factors were identified. The first two factors had eigen value of 5.28 and 2.05 respectively while only four factors accounted for 81.47% of the total variance. The two analysis methods indicated vine length, leaf size, number of branches, vine diameter, number of leaves, petiole length as traits that contributed more to the total variation observed and as such can be used in discriminating among the genotypes. Configurations of the 20 genotypes along the first three principal component axes shows that L4, N4, N3, O1, E1, A1, N1 and A3 were most distant from all other genotypes and are high yielding in terms of vine length, number of branches and leaf size therefore can be selected directly. The complementarity effect of the principal component analysis and factor analysis, suggest the existence of genetic variability among the genotypes.