627 research outputs found

    Character association and path analysis in grain sorghum

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    Association and path analysis between hill count, bloom, plant height, panicle length, panicle count, 1000 seed mass, head weight and grain yield of thirty sorghum varieties were studied over two locations and years. There is significant high positive correlation between grain yield and head weight (r=0.976), grain yield and 1000 grain mass (r=0.522) and 1000 grain mass and head weight (r=0.528). Similarly, significant but negative correlation exists between panicle count and panicle length. Partitioning of yield and yield components into direct and indirect effects revealed that head weight had the highest direct effect on grain yield (0.961) while 1000 grain mass contributed indirectly to grain yield via head weight (0.507). Panicle count also contributed to grain yield indirectly through head weight (0.420) indicating the importance of head weight as one of the most important yield components followed by 1000 grain mass and then panicle count. There is high positive phenotypic and genotypic correlation coefficient between hill and panicle count, panicle count and head weight, panicle count and grain yield and head weight and grain yield. Plant height has high positive phenotypic and genotypic correlation coefficients with head weight (rp= 0.550, rg=0.881) and grain yield (rp=0.555, rg=0.904)

    Yield stability analysis of pearl millet hybrids in Nigeria

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    Genotype x environment interaction in pearl millet [Pennisetum glaucum (L.) R.Br.] was studied for grain yield by growing 90 genotypes consisting of 81 hybrids and 9 inbred parents at 5 locations for 2 years. Genotype x environment interaction was observed, a large component of which was accounted for by non-linear regression on the environment means. Although the linear portion was significant, its magnitude was smaller than that of the non-linear component indicating the significance of environmental effects on the genotypes. Six hybrids were found to be stable across the environments. They yielded above the average mean yield of all the genotypes under test, with a slope of unity and the mean square due to deviation from regression equal to zero.Keywords: Genotype x environment interaction, yield, stability, pearl mille

    Preliminary Evaluation of Some Qualitative Traits of Sugarcane Germplasm of North-Western Nigeria

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    Thirty five local sugarcane (Saccharum spp.) accessions were collected in an expedition in North-Western Nigeria, covering Sokoto, Kebbi, Zamfara,  Katsina, Kaduna, Kano and Jigawa States in September 2011. The germplasm accessions were maintained at Usmanu Danfodiyo University Sokoto. Data on leaf colour, leaf sheath colour, thrashability, ligular process, spines  (pubescence), stem colour and bud groove were collected. The study indicate that shape of the accessions could be used either directly or indirectly as a selection tool for pest resistance and mechanical cultivation in sugarcane. Leaf sheath colour and number of green leaves per plant could form additional selection tools for high photosynthesis efficiency to the already existing ones.Key words: Evaluation, Sugarcane, Germplasm, Characters, Accession

    Genetic variability and heritability studies of some reproductive traits in cowpea (Vigna unguiculate (L.) Walp.)

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    The success of most crop improvement programs largely depends upon the genetic variability and the heritability of desirable traits. The magnitude and type of genetic variability help the breeder to determine the selection criteria and breeding schemes to be used for improvement purposes. A screen house experiment was carried out at Samaru, Nigeria in 1999 and 2000 dry seasons to estimate the genotypic variability of some reproductive traits and their heritability in some selected cowpea varieties. Results of the study showed that there was considerable variation among cultivars for duration of reproductive phase and rate of photosynthate partitioning. Genotypic coefficients of variation were also high for days to first flower, 100-seed weight, plant height, and harvest index. Broad-sense heritability estimate (h2) was 98.9% for 100-seed weight, 94% for duration of reproductive phase, 84.5% for days to first flower, 83.9% for days to maturity, and 77.3% for harvest index. This information showed that there is sufficient genetic variance to warrant selection for improvement in the cowpea genotypes studied. We concluded that considerable progress in cowpea breeding could be achieved by exploiting these traits

    Effect of imazapyr treated maize on Striga infestation and time of intercropping cowpea in Samaru, Nigeria

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    Two field experiments were conducted at the research farm of Institute for Agricultural Research (IAR) Samaru, Zaria during the 2011 cropping season, with the aim of determining the effect of imazapyr treated maize on Striga infestation and time of intercropping cowpea in Samaru, northern guinea savannah of Nigeria. There were two sets of experiments: the first experiment consisted of Six (6) hybrids (AS1128-1, AS1128-2, AS1128-3, AS1128-4, AS1128-6 and AS1128-8) of imazapyr resistant (IR) maize seeds treated with imazapyr chemical and intercropped with cowpea at 2, 4 and 6 weeks after sowing (WAS) of maize. The second experiment consisted of the same Six (6) hybrids of IR maize seeds but untreated and also intercropped with cowpea at 2, 4 and 6 WAS of maize. The experiments were laid out in a split plot design with time of intercropping cowpea as main plot and hybrid maize varieties as sub plot, and replicated three times. The cowpea variety used for the trial was IT97K-499-35. Among the treated IR-maize hybrids, only AS1128-1, AS1128-2, AS1128-3 and AS1128-4 germinated while for the untreated, all the six hybrids germinated. The grain yields per hectare of all the treated maize hybrids did not significantly differed whereas grain yields per hectare of the untreated maize hybrids AS1128-1, AS1128-2, AS1128-3 and AS1128-4 were significantly higher than the hybrid AS1128-8. The treated IR  maize hybrids exerted 100% control of Striga while the untreated supported Striga emergence. There was no visible damage symptoms observed on the cowpea intercropped with treated maize at all times of intercropping. It is therefore concluded that the IR-maize hybrids ASII28-1, ASII28-2, ASII28-3 and ASII28-4 should be used in the treated forms for the control of Striga. Moreover, the intercropping of cowpea with imazapyr treated maize can be carried out starting from 2 WAS of maize.Key words: Intercropping, imazapyr resistant maize (IR-maize), cowpea, Striga

    Importance of Ethnicity, CYP2B6 and ABCB1 Genotype for Efavirenz Pharmacokinetics and Treatment Outcomes: A Parallel-group Prospective Cohort Study in two sub-Saharan Africa Populations.

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    We evaluated the importance of ethnicity and pharmacogenetic variations in determining efavirenz pharmacokinetics, auto-induction and immunological outcomes in two African populations. ART naïve HIV patients from Ethiopia (n = 285) and Tanzania (n = 209) were prospectively enrolled in parallel to start efavirenz based HAART. CD4+ cell counts were determined at baseline, 12, 24 and 48 weeks. Plasma and intracellular efavirenz and 8-hydroxyefvairenz concentrations were determined at week 4 and 16. Genotyping for common functional CYP2B6, CYP3A5, ABCB1, UGT2B7 and SLCO1B1 variant alleles were done. Patient country, CYP2B6*6 and ABCB1 c.4036A>G (rs3842A>G) genotype were significant predictors of plasma and intracellular efavirenz concentration. CYP2B6*6 and ABCB1 c.4036A>G (rs3842) genotype were significantly associated with higher plasma efavirenz concentration and their allele frequencies were significantly higher in Tanzanians than Ethiopians. Tanzanians displayed significantly higher efavirenz plasma concentration at week 4 (p<0.0002) and week 16 (p = 0.006) compared to Ethiopians. Efavirenz plasma concentrations remained significantly higher in Tanzanians even after controlling for the effect of CYP2B6*6 and ABCB1 c.4036A>G genotype. Within country analyses indicated a significant decrease in the mean plasma efavirenz concentration by week 16 compared to week 4 in Tanzanians (p = 0.006), whereas no significant differences in plasma concentration over time was observed in Ethiopians (p = 0.84). Intracellular efavirenz concentration and patient country were significant predictors of CD4 gain during HAART. We report substantial differences in efavirenz pharmacokinetics, extent of auto-induction and immunologic recovery between Ethiopian and Tanzanian HIV patients, partly but not solely, due to pharmacogenetic variations. The observed inter-ethnic variations in efavirenz plasma exposure may possibly result in varying clinical treatment outcome or adverse event profiles between populations

    Wavelet Cycle Spinning Denoising of NDE Ultrasonic Signals Using a Random Selection of Shifts

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    Wavelets are a powerful tool for signal and image denoising. Most of the denoising applications in different fields were based on the thresholding of the discrete wavelet transform (DWT) coefficients. Nevertheless, DWT transform is not a time or shift invariant transform and results depend on the selected shift. Improvements on the denoising performance can be obtained using the stationary wavelet transform (SWT) (also called shift-invariant or undecimated wavelet transform). Denoising using SWT has previously shown a robust and usually better performance than denoising using DWT but with a higher computational cost. In this paper, wavelet shrinkage schemes are applied for reducing noise in synthetic and experimental non-destructive evaluation ultrasonic A-scans, using DWT and a cycle-spinning implementation of SWT. A new denoising procedure, which we call random partial cycle spinning (RPCS), is presented. It is based on a cycle-spinning over a limited number of shifts that are selected in a random way. Wavelet denoising based on DWT, SWT and RPCS have been applied to the same sets of ultrasonic A-scans and their performances in terms of SNR are compared. In all cases three well known threshold selection rules (Universal, Minimax and Sure), with decomposition level dependent selection, have been used. It is shown that the new procedure provides a good robust denoising performance, without the DWT fluctuating performance, and close to SWT but with a much lower computational cost.This work was partially supported by Spanish MCI Project DPI2011-22438San Emeterio Prieto, JL.; Rodríguez-Hernández, MA. (2015). Wavelet Cycle Spinning Denoising of NDE Ultrasonic Signals Using a Random Selection of Shifts. 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    Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015

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    SummaryBackground The Global Burden of Diseases, Injuries, and Risk Factors Study 2015 provides an up-to-date synthesis of the evidence for risk factor exposure and the attributable burden of disease. By providing national and subnational assessments spanning the past 25 years, this study can inform debates on the importance of addressing risks in context. Methods We used the comparative risk assessment framework developed for previous iterations of the Global Burden of Disease Study to estimate attributable deaths, disability-adjusted life-years (DALYs), and trends in exposure by age group, sex, year, and geography for 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks from 1990 to 2015. This study included 388 risk-outcome pairs that met World Cancer Research Fund-defined criteria for convincing or probable evidence. We extracted relative risk and exposure estimates from randomised controlled trials, cohorts, pooled cohorts, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. We developed a metric that allows comparisons of exposure across risk factors—the summary exposure value. Using the counterfactual scenario of theoretical minimum risk level, we estimated the portion of deaths and DALYs that could be attributed to a given risk. We decomposed trends in attributable burden into contributions from population growth, population age structure, risk exposure, and risk-deleted cause-specific DALY rates. We characterised risk exposure in relation to a Socio-demographic Index (SDI). Findings Between 1990 and 2015, global exposure to unsafe sanitation, household air pollution, childhood underweight, childhood stunting, and smoking each decreased by more than 25%. Global exposure for several occupational risks, high body-mass index (BMI), and drug use increased by more than 25% over the same period. All risks jointly evaluated in 2015 accounted for 57·8% (95% CI 56·6–58·8) of global deaths and 41·2% (39·8–42·8) of DALYs. In 2015, the ten largest contributors to global DALYs among Level 3 risks were high systolic blood pressure (211·8 million [192·7 million to 231·1 million] global DALYs), smoking (148·6 million [134·2 million to 163·1 million]), high fasting plasma glucose (143·1 million [125·1 million to 163·5 million]), high BMI (120·1 million [83·8 million to 158·4 million]), childhood undernutrition (113·3 million [103·9 million to 123·4 million]), ambient particulate matter (103·1 million [90·8 million to 115·1 million]), high total cholesterol (88·7 million [74·6 million to 105·7 million]), household air pollution (85·6 million [66·7 million to 106·1 million]), alcohol use (85·0 million [77·2 million to 93·0 million]), and diets high in sodium (83·0 million [49·3 million to 127·5 million]). From 1990 to 2015, attributable DALYs declined for micronutrient deficiencies, childhood undernutrition, unsafe sanitation and water, and household air pollution; reductions in risk-deleted DALY rates rather than reductions in exposure drove these declines. Rising exposure contributed to notable increases in attributable DALYs from high BMI, high fasting plasma glucose, occupational carcinogens, and drug use. Environmental risks and childhood undernutrition declined steadily with SDI; low physical activity, high BMI, and high fasting plasma glucose increased with SDI. In 119 countries, metabolic risks, such as high BMI and fasting plasma glucose, contributed the most attributable DALYs in 2015. Regionally, smoking still ranked among the leading five risk factors for attributable DALYs in 109 countries; childhood underweight and unsafe sex remained primary drivers of early death and disability in much of sub-Saharan Africa. Interpretation Declines in some key environmental risks have contributed to declines in critical infectious diseases. Some risks appear to be invariant to SDI. Increasing risks, including high BMI, high fasting plasma glucose, drug use, and some occupational exposures, contribute to rising burden from some conditions, but also provide opportunities for intervention. Some highly preventable risks, such as smoking, remain major causes of attributable DALYs, even as exposure is declining. Public policy makers need to pay attention to the risks that are increasingly major contributors to global burden. Funding Bill & Melinda Gates Foundation
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