Identification of additional/novel QTL associated with resistance to cassava green mite in a biparental mapping population

Open Access JournalCassava green mite [CGM, Mononychellus tanajoa (Bondar)] is the most destructive dry-season pest in most cassava production areas. The pest is responsible for cassava fresh root yield losses of over 80%. Deployment of CGM resistant cultivars is the most cost-effective and sustainable approach of alleviating such production losses. The purposes of this study were to validate the stability of CGM resistance genes found in previously published results, to identify new genes for CGM resistance in bi-parental mapping population and estimate the heritability of the trait. A total of 109 F1 progeny derived from a cross between CGM resistant parent, TMEB778 and a very susceptible parent, TMEB419 were evaluated under CGM hotspot areas in Nigeria for two cropping seasons. A total of 42,204 SNP markers with MAF ≥ 0.05 were used for single-marker analysis. The most significant QTL (S12_7962234) was identified on the left arm on chromosome 12 which explained high phenotypic variance and harboured significant single nucleotide polymorphism (SNP) markers conferring resistance to CGM and leaf pubescence (LP). Colocalization of the most significant SNP associated with resistance to CGM and LP on chromosome 12 is possibly an indication of a beneficial pleiotropic effect or are physically linked. These significant SNPs markers were intersected with the gene annotations and 33 unique genes were identified within SNPs at 4 – 8MB on chromosome 12. Among these genes, nine novel candidate genes namely; Manes.12077600, Manes.12G086200, Manes.12G061200, Manes.12G083100, Manes.12G082000, Manes.12G094100, Manes.12G075600, Manes.12G091400 and Manes.12G069300 highly expressed direct link to cassava green mite resistance. Pyramiding the new QTL/genes identified on chromosome 12 in this study with previously discovered loci, such on chromosome 8, will facilitate breeding varieties that are highly resistant CGM

Genome-wide association analysis reveals new insights into the genetic architecture of defensive, agro-morphological and quality-related traits in cassava

OpenAccess Article; Published online: 30 Jul 2020Cassava (Manihot esculenta) is one of the most important starchy root crops in the tropics due to its adaptation to marginal environments. Genetic progress in this clonally propagated crop can be accelerated through the discovery of markers and candidate genes that could be used in cassava breeding programs. We carried out a genome-wide association study (GWAS) using a panel of 5,310 clones developed at the International Institute of Tropical Agriculture - Nigeria. The population was genotyped at more than 100,000 SNP markers via genotyping-by-sequencing (GBS). Genomic regions underlying genetic variation for 14 traits classified broadly into four categories: biotic stress (cassava mosaic disease and cassava green mite severity); quality (dry matter content and carotenoid content) and plant agronomy (harvest index and plant type). We also included several agro-morphological traits related to leaves, stems and roots with high heritability. In total, 41 significant associations were uncovered. While some of the identified loci matched with those previously reported, we present additional association signals for the traits. We provide a catalogue of favourable alleles at the most significant SNP for each trait-locus combination and candidate genes occurring within the GWAS hits. These resources provide a foundation for the development of markers that could be used in cassava breeding programs and candidate genes for functional validation

Full Development Of Pseudopotentials That Work For All Elements

The form factors of pseudopotential that works for all elements is fully developed. The plane wave matrix element of pseudopotential is evaluated. In addition, the linear coefficients parameter A¡ are calculated by the use of tables of Bachelet et al. (1982) as well as the prescription of Pattnaik et al.(1979) which eliminated the numerical instability problems. The liquid metal resistivity is evaluated using Simpson's rule. Keywords: Pseudopotential, liquid metal resistivity, matrix element, linear coefficients, inverse orthogonality transformation. Nigerian Journal of Physics Vol. 19 (1) 2007: pp. 23-3

Calculation Of Phonon Dispersion Frequencies For Bcc Tantalum Using Resonance Pseudopotential Model

The phonon dispersion frequencies are calculated from first principles for bcc Tantalum using a resonance pseudopotential model. It was also possible, using this scheme, to account for the anomalous feature of the Ta dispersion curve observed experimentally in the (&#949,o,o,) direction where the frequencies of the transverse branch are higher than the frequencies of the longitudinal branch. The frequencies obtained were also used to calculate the phonon density of states by the linear – analytic tetrahedral method of zone integration. The results of these calculations are qualitatively in good agreement with experimental data, and provide further support to the interpretation of the anomalous behaviour in the (&#949,o,o,) direction as arising from s-d hybridization. Keywords: Phonon dispersion, phonon frequency, resonance, pseudopotential model, Phonon density of states. Nigerian Journal of Physics Vol. 19 (1) 2007: pp. 17-2

An inverse-scattering approach to the physics of transition metals.

A method is developed for the deduction of a transition metal ion potential from a knowledge of the phase-shift. The method used is based the distorted plane – wave scattering approximation for the deduction of non singular potentials from scattering phase shifts in an inverse scattering approach. The resulting electron – ion potential obtained is a finite Dirichlet series sum of short-range exponential functions. The Fourier transform of the potential is obtained for applications to the transition metals. Global Journal of Pure and Applied Sciences Volume , No 1 January (2001) pp. 153-160 KEY WORDS: Transition metal ion-potential, Phase-shift, Plane-wave, Scattering – approximation

Modelling and analysis of radiative heat transfer mechanism of solar heater cover and absorber plate

No Abstract.Nigerian Journal of Physics Vol. 20 (1) 2008: pp.76-8

Current and future advances in genomics-assisted cassava breeding

Published online: 11 May 202

Knowledge, Attitude and Practices of Diabetic Patients in the United Arab Emirates

INTRODUCTION: Diabetes self-management education is a cornerstone of diabetes care. However, many diabetics in the United Arab Emirates (UAE) lack sufficient knowledge about their disease due to illiteracy. Thus, before considering any possible intervention it was imperative to assess present knowledge, attitudes, and practices of patients towards the management of diabetes. METHODS: A random sample of 575 DM patients was selected from diabetes outpatient's clinics of Tawam and Al-Ain hospitals in Al-Ain city (UAE) during 2006–2007, and their knowledge attitude and practice assessed using a questionnaire modified from the Michigan Diabetes Research Training Center instrument. RESULTS: Thirty-one percent of patients had poor knowledge of diabetes. Seventy-two had negative attitudes towards having the disease and 57% had HbA(1c) levels reflecting poor glycemic control. Only seventeen percent reported having adequate blood sugar control, while 10% admitted non-compliance with their medications. Knowledge, practice and attitude scores were all statistically significantly positively, but rather weakly, associated, but none of these scores was significantly correlated with HbA(1c). CONCLUSIONS: The study showed low levels of diabetes awareness but positive attitudes towards the importance of DM care and satisfactory diabetes practices in the UAE. Programs to increase patients' awareness about DM are essential for all diabetics in the UAE in order to improve their understanding, compliance and management and, thereby, their ability to cope with the disease