Morphological Characterization, Variability and Traits Association among Accessions of Three Species of Crassocephalum (Moench.) S. Moore from Nigeria

Crassocephalum species have served as vegetables for decades, yet they remain undomesticated and uncultivated. The knowledge of the variability and traits association of these species could enhance the improvement and thus facilitate their domestication and cultivation. Twenty-one accessions of Crassocephalum species were characterized in a Randomized Complete Block Design to determine intra and inter-specifies variability and traits association for their improvement with a view to facilitate their domestication and cultivation. One way Analysis of Variance (ANOVA), Principal Component Analysis (PCA), and correlation coefficients were used to analyze the data. The results revealed significant intra and inter-specifies variability among the accessions characterized. The first three axes of PCA accounted for over 60% of total variation with leaf length, leaf width, days to 50% flowering, days to maturity, number of achenes/head and number of filled achenes/head as discriminants. Positive and significant phenotypic correlations were observed between leaf length and leaf width with petiole length, internode length, peduncle length, and number of days to maturity. High positive correlation was observed for number of capitula/plant with capitulum diameter and number of filled achenes per head. Hence, the principal contributors to total variation which are leaf length, leaf width, days to 50% flowering, days to maturity, number of achenes/head and number of filled achenes/head are hereby suggested to breeders in developing a suitable breeding programme for Crassocephalum crepidioides, C. rubens and C. togoense

Global wealth disparities drive adherence to COVID-safe pathways in head and neck cancer surgery

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Application of SSR Markers for Genetic Purity Analysis of Parental Inbred Lines and Some Commercial Hybrid Maize (Zea mays L.)

Aims: Morphological evaluation of seeds and growing plants used for certification for purity and variety distinctness in Nigeria is time consuming and expensive. This experiment set to evaluate the usefulness of SSR markers to determine genetic purity of commercial hybrids and their inbred lines. Place and Duration of Study: Bioscience unit, International Institute of Tropical Agriculture, Nigeria in December, 2011 Methodology: Seedlings of four F1 hybrids and four inbred lines were grown in the screen house of IITA for DNA extraction using Dellaporta method with some modifications. Six Simple Sequence Repeat (SSR) markers were used for Polymerase Chain Reaction (PCR) using Touch-Down PCR profile. The analysis is by fragment analysis as present (1) or absent (0) Mathematical equation to determine genetic purity of the genotypes was developed from the genetic distances matrix. Results: Simple descriptive analysis revealed that average genetic diversity and polymorphism information content (PIC) recorded by the markers was 0.592 and 0.512 respectively. Genetic purity level of inbred lines ranged between 91.3% and 98.7% while the hybrids ranged between 81.3% and 95%. Conclusion: SSR markers are powerful biotechnological tool capable of detecting genetic purity status of Nigerian maize hybrids therefore inclusion of DNA analysis of seeds using SSR markers to determine genetic purity of maize seed is recommended. However, further research work with larger number of seed samples per variety will be needed to validate reliability

Molecular Characterization and DNA Fingerprinting of Xanthomonas oryzae pv. oryzae Isolates from Climate Change Prone Areas in East Africa

Genomic DNA fingerprinting is a useful tool for effective and reliable identification and differentiation of Xanthomonas oryzae pv. oryzae (Xoo) pathogen from rice. The study aimed to conduct molecular characterization and DNA fingerprinting of 23 Xoo isolates from East Africa and two Xoo isolates from IRRI (Philippines) as control. PCR analysis was carryout on genomic DNA of 25 Xoo isolates using 6 Xoo specific primer pairs. Cluster analyses of genetic data obtained from 25 Xoo DNA fingerprints revealed two major genotypes (GrpA and GrpB) among the 25 Xoo isolates. GrpA has three subgroups (GrpA1; GrpA2; GrpA3) and GrpB (GrpB1; GrpB2; GrpB3). GrpA genotype consists of 20 Xoo isolates from Uganda, Rwanda and Philippines while GrpB genotype has 5 Xoo isolates from Rwanda. Some Xoo isolates were identical (PX-1, PX-2; UX621, RX2101; RX554, UX623, RX4113; UX211, UX213, UX214, RX4112, UX215). The emergence of subgroup genotypes could possibly be due to mutations and interactions among isolates and strains in host cells. Some Xoo isolates from Rwanda and Uganda were identical suggesting possible pathogen migration between these countries and long-term survival. Durable resistance rice cultivars would need to overcome both GrpA and GrpB Xoo genotypes in order to survive after their deployment into different rice ecologies in East Afric