Geographical patterns of phenotypic diversity in <Emphasis Type="Italic">Oryza sativa</Emphasis> landraces of Côte d’Ivoire

The knowledge of agro-morphological diversity and the distribution pattern of variation among conserved accessions could be an invaluable aid in germplasm management and crop improvement strategies. In this study, the geographical pattern of morphological variation of 880 landrace rice (Oryza sativa (L.)) accessions in Côte d’Ivoire was evaluated for 13 agro-morphological characters. Shannon –weaver diversity index indicated an overall mean of 0.47 ± 0.07 in the collection, with the greatest diversity from derived Savanna and north-west (H′ = 0.52 and 0.50) while the west-central had the lowest diversity (H′ = 0.41). Canonical discriminant analysis showed that traits such as panicle length, grain size (weight and length), tillering ability, number of days to heading and maturity were the main discriminatory characteristics. Result of the phenotypic frequency shows that, the landraces from the north and north-western zones were mostly tall, early heading and maturity, compared to those from the west and west-central which were mainly dwarf to medium height, late heading and maturing. This differential distribution of landraces with height, heading and maturity period reflected the distribution pattern of different Oryza sativa landraces in Côte d’Ivoire, which could be useful in germplasm management and breeding programs.     

Factors affecting egg production and layer bird mortality in private poultry farms in the subhumid zone of Nigeria

Egg production and layer bird mortality data obtained from five different private farms in Zaria within the subhumid zone of Nigeria, over a 6‐year period (1994–1999) were subjected to least squares analysis to determine the effects of age, season and year. It was demonstrated that age had a highly significant influence (P < 0.01) on egg production in that birds falling within the age group 30–39 weeks produced the highest number of eggs (3255 ± 109), while birds over 100 weeks of age produced the lowest number of eggs (1206 ± 412). Similarly, seasonal variation in egg production was also significant (P < 0.05); the highest egg production (2926 ± 90) was obtained during the early dry season, and the lowest (2423 ± 95) during the late wet season. Mortality was generally low (0.0–0.9%) and not significantly different from 20 to 49 weeks of age (P > 0.05). However, from 50 to 100 weeks of age, highly significant differences (P < 0.01) in mortality were observed, with the 90–100 weeks age group recording the highest mortality of 15.7 ± 1.3%. Furthermore, yearly variations in egg production and mortality were highly significant (P < 0.01) with 1999 producing the most eggs (4410 ± 102) and recording the lowest mortality (1.4%). It was concluded that due to the significant seasonal, age and yearly variations, data on egg production and mortality need to be adjusted for these effects to enable unbiased comparison between and within farms. Furthermore, farmers can make adequate feeding preparations commensurate with each season for optimal egg production.     

水稻萌发耐淹性种质资源筛选及QTL定位

作者用水培的方法研究水稻不同生育期缺磷的影响,结果证明：幼苗期缺磷的影响最显著,表现出生长缓慢,分蘖减少。因此,栽培水稻在幼苗期及分蘖期充分供应磷肥有特别重要意义。     

Effects of pyrethroid insecticide exposure on haematological and haemostatic profiles in rats

High malaria burden has led to the increase use of insecticides in the tropics and subtropics. This study thus aimed at assessing the haematological effects and associated haemostatic alteration of pyrethroid insecticide exposure using experimental animal model. Rats of comparable ages and weights were randomized into four groups (A-D). Rats in groups B, C and D were exposed to pyrethroid insecticide by inhalation for 1, 2 and 3 min daily respectively for three weeks. Rats in group A (control) were not exposed. Haematological and haemostatic variables were comparable in all groups (< 0.05). Results from the study show that minimal exposure to pyrethroids is safe.     

Transmission and storage properties of a tropical loamy sand soil as influenced by organic-based and inorganic fertilizers

Short-term effect of organic and inorganic amendments on soil physical quality (SPQ) is marked when dealing with tropical soils which are naturally exposed to a high risk of water erosion. This study assessed the suitability of Tithonia diversifolia (Mexican Sunflower) when incorporated as green manure (GM) and also composted with poultry manure (PM) and other organic-based and inorganic fertilizers to improve some hydraulic properties of an Alfisol subject to excessive drainage. Treatments applied include fresh T. diversifolia (GM), PM, T. diversifolia composted with PM, organo-mineral fertilizers (OMF), neem fertilizer (NF), inorganic fertilizer (20-10-10 NPK), and control in a randomized complete block design and replicated four times. Soil samples were collected at 0–20 cm depth to determine near steady-state infiltration rates (I_s), sorptivity, transmissivity, saturated hydraulic conductivity (K_s), macroporosity (MacP), microporosity (MicP), air capacity (AC), and relative water capacity (RWC). The I_s rates were significantly (P ≤ 0.05) reduced to optimum range with the addition of the organic fertilizers over very high value (128.7 cm hr^?1) observed for control. Whereas, K_s was enhanced in the order: GM > compost (CP) > NF > inorganic fertilizer > control > organo-mineral fertilizer > PM. Sorptivity and transmissivity were highest in control and inorganic fertilizer plots, indicating that the addition of organic fertilizers lowered these parameters while MacP, MicP, AC, and RWC were generally increased with the addition of organic-based and inorganic fertilizers. Specifically, NF increased MicP by 34% over control. Values for RWC which were within the optimum range (0.60–0.70) were only obtained with NF (0.74), OMF (0.72), NPK (0.70), and GM (0.60). The SPQ parameters assessed in this study were enhanced by the addition of fresh T. diversifolia applied as GM and CP compared to other treatments. Therefore, T. diversifolia usually burned by farmers should instead be incorporated into the soil as manure.     

Demographic Survey of Tree Species in Urban Centers of Ekiti State,Nigeria

A combination of social surveys and direct field observations was used to identify and enumerate the tree species that are presently planted in and around the urban centers in the three zones of Ekiti State, Nigeria. A total of 62 tree species belonging to 27 families were sampled as urban tree species in the study area. Products derived from these trees ranged from edible fruits, cash income, medicine, fuel, shade, and wind control. The various similarity measures revealed that similar species of trees occurred as urban tree species in the three zones of the study area. Interviews with the various respondents revealed that all of them were tree minded irrespective of their sex, age, educational, economic, and religious status. Thus, these features were not regarded as prerequisites to tree mindedness in the study area. Field observation revealed that urban forestry is still poor in the state and at present the products derivable from the trees influenced the choice of species planted by the respondents. Thus, the various advantages derivable from the urban tree species, coupled with the tree mindedness of the respondents, could be utilized to serve as viable incentives to tree cultivation—especially in Nigeria where previous efforts had concentrated on farm and industrial forestry.     

Influence of processing cassava peels on the hydrogen cyanide concentration, nutritive value and performance of growing rabbits

Forty-eight rabbits used to investigate the response of growing rabbits to diets containing differently processed cassava peel meals were divided into four groups balanced for sex and weight. These groups were then assigned at random to the experimental treatments. Four diets were formulated such that the diets contained 200 g/kg of the experimental feedstuffs, sun-dried cassava peel meal (S), ensiled cassava peel meal (E) and retted cassava peel meal (R), and the control did not contain any cassava peels. Hydrogen cyanide (HCN) concentration in the processed cassava peel meal was lower relative to the unprocessed meal. It was, however, lowest in R and highest in E. With the exception of S, fibre fractions were lower in the processed meal compared to the unprocessed meal. The E depressed (p < 0.05) feed and digestible nutrient intakes, weight gain, nutrient digestibility, digestible protein (DP), digestible energy (DE) and DP/DE ratio but increased protein intake to gain and feed to gain ratios compared to other diets. Intake of HCN decreased (p < 0.05) successively in this order: R, S and E. The results indicate that retting and sun-drying are more effective in cassava peel detoxification than ensiling, and dietary HCN concentration and intake of 56 and 4 mg/kg BW, respectively, were not toxic under the conditions of the experiment.