Rivers State University of Science and Technology

About: Rivers State University of Science and Technology is a education organization based out in Port Harcourt, Rivers, Nigeria. It is known for research contribution in the topics: Population & Threatened species. The organization has 1826 authors who have published 1833 publications receiving 15183 citations.

Preliminary studies of in vitro stimulation of sexual mating among isolates of Mycosphaerella fijiensis , causal agent of black sigatoka disease in bananas and plantains

Abstract: Single-ascospore-derived isolates ofMycosphaerella fijiensis Morelet from false horn ‘Agbagba’ plantain leaves obtained from five different villages in southern Nigeria were stimulated to mate under artificial conditions. Pairs of isolates were incubated under blacklight on potato dextrose agar (PDA) with surface-sterilized plantain leaves or on PDA with autoclaved plantain leaves. Some isolates were observed to be sexually compatible by their ability to produce spherical to bulb-shaped fruiting body structures (FBS) and ascospores on pairing. FBS were observed to measure between 39–65 µm (smallest diameter) and 39–104 µm (largest diameter; mean 55.3×71.1 µm) in diameter, whereas ascospore lengths measured between 13.0 and 14.9 µm. Length of incubation time required for FBS production was dependent on the pair of isolates involved, the average being 40.1 days. With some pairs, ascospores were observed after 35 days of incubation.

Nutrient recycling potential of Tephrosia candida in cropping systems of southeastern Nigeria

Abstract: Improving fallow quality in cassava–fallow rotations in southeastern Nigeria through the use of leguminous cover crops has been shown to sustain the productivity of such systems. We studied the effects of age (1 or 2 years) of Tephrosia candida fallow on biomass and nutrient accumulation, on weed biomass and yield response of cassava/maize intercrop and on changes in soil chemical properties in a 3 yr field trial. Results were compared with those obtained in natural fallow. Total biomass and litter were three times higher in plots fallowed for 2 yr with Tephrosia candida than in those under natural fallow for the same period. Weed biomass was 205% lower in T. candida plots fallowed for 2 yr than in the natural fallow and was 174% smaller in T. candida plots fallow for 1 yr than in the natural fallow. Nutrient (nitrogen, phosphorus, calcium, magnesium and potassium) yields in leaves of T. candida fallow for 2 yr were on average 200–300% higher than in leaves of other fallows. The same trend was observed for cassava and maize yields. Soil chemical changes at soil depth 0 to 5 cm showed significant increases in N and C concentrations after 2 yr fallowing and a year of cropping, particularly in the planted fallow plots. Conversely, soil pH, available P and the exchangeable cations, especially Ca were lower, while Al was higher than the initial values, mainly in plots fallowed under T. candida, indicating a tendency of this fallow species to further exacerbate the soil acidification problem of the acid Ultisol at the study site in southeastern Nigeria.

Known from a handful of specimens: analyzing the worldwide patterns of occurrence and conservation of rodents and shrews recorded only from the type locality

Abstract: Traditionally, conservation research has not focused on Rodentia and Soricomorpha, and many species are known from a handful of specimens and the type locality only (few and type locality species (FETP)). Here we studied the patterns of occurrence of FETP rodents and soricomorphs in relation to geographical area and vegetation zones and report some conservation considerations. Overall, 91 species of Rodentia and 19 species of Soricomorpha were selected. There was a positive correlation between number of species per genus and number of FETP species in each genus. The majority of FETP rodents occur in the Neotropical, Afrotropical and Oriental regions, and soricomorphs in the Afrotropical and Oriental regions. Higher numbers of FETP rodent species occurred in Argentina and Indonesia. There was a positive relationship between species richness of rodents per country and number of FETP species. In terms of habitat type, FETP species of rodents and soricomorphs showed similar patterns, with most species being found in rainforest. The great majority of selected species of both groups were Data Deficient (DD), with Critically Endangered (CR) accounting for 16.5% of Rodentia and 5.3% of Soricomorpha. Overall, IUCN threatened species mostly occur in the Neotropical region, followed by the Afrotropical region. It is urged that IUCN authorities should promptly revise all FETP species and their precautionary CR status, at least when a reasonable timespan (i.e., >25 years) has passed since the last records.