Nigerian Journal of Genetics最新文献

Random amplified Polymorphic DNA polymerase chain reaction (RAPD DNA-PCR) was employed to access the genetic variability and phylogenetic relationship among pig populations in Imo State. Genomic DNA from 50 pigs comprising of at least 10 pigs per geopolitical zone of Imo state were extracted and two highly polymorphic primers utilized to estimate variability, phylogenetic relationship among the pigs and their genetic diversity. The genetic distance and genetic identity estimated showed that genetic distances (D) calculated ranged between 0.0300 (Songhai vs FUTO) and 0.1497 (Mbaise vs Awo-Idemili), while the genetic identity (I) calculated ranged between 0.8610 (Mbaise vs Awo-Idemili) and 0.9704 (Songhai vs FUTO). Similarity was observed between Songhai, Mbaise and FUTO populations, while Mbano and Awo–idemili exhibited dissimilarity. The phylogenetic tree showed that Songhai, FUTO and Mbaise populations are more closely related while Mbano and Awo-idemili are more genetically distant. The standard genetic diversity (h*) of total population ranged from 0.0001 to 0.4998 with an average of 0.3208, while Shannon's information index (I*) ranged from 0.0001 to 0.6929 with a mean of 0.4762. This study shows that genetic diversity of the RAPD DNA polymorphs amongst pig populations in Imo State is low while the genetic relationship between the different populations varies from population to population.

Fifteen elite yellow maize inbred lines were evaluated in a randomized complete block design experiment with three replicates in 2014. Data were collected on days to anthesis and silking, anthesis-silking interval, plant and ear heights, number of ears per plant, leaf area, ear weight and grain yield. Mean values were used to determine characters' phenotypic and genotypic variances, phenotypic, genotypic and environmental coefficients of variation. Broad sense heritability and genetic advance percentage of mean were estimated for each trait. Significant variation existed in all the characters. The coefficients of variation were low except for ear weight and grain yield that were relatively higher. The anthesis-silking interval was highest in lines TZEI 124 and TZEI 16, but least in lines BD74-222, TZEI 11 and TZEI 13. Line BD74-222 had the height plant height and BD74-165 had the least. Line TZEI 124 produced highest maize grain yield whereas line TZEI 146 had the least. Coefficients of variation of phenotype and genotype were low for all the traits except number of ear per plant, ear and grain yield. The characters were less influenced by the environment thus the traits can be used for selection. Heritability was greater than 80% for all characters studied whereas expected genetic advance ranged from low (8.91) in days to silking to high (72.03) in number of ear per plant. Days to anthesis and silking, plant height and number of leaf per plant were positively correlated. Grain yield was positively correlated with ASI, plant and ear heights, number of leaf per plant and leaf area. High heritability and high genetic advance for ASI indicated the presence of additive genes in the trait and suggested reliable maize improvement through selection of the traits. In this study moderate genetic advance was associated with high heritability.

Germplasm identification and characterization is an important link between conservation and utilization of plant genetic resources. The present study was conducted to characterize the morphological diversity of 10 germplasm accessions of Finger millet (Eleusine coracana (L) Gaertn) collected from diverse locations spread across the geographic Northern Nigeria during the 2008, 2009 and 2010 cropping seasons. The seeds of the accessions were planted in a randomized complete block design (RCBD) with three replications in each of two locations-Keffi and Gwagwalada, during the three cropping seasons. The field studies for the three seasons in the two locations followed uniform agricultural practices. Field data was collected on morphological traits such as plant height, leaf length, leaf diameter, finger length, finger width, number of fingers and 1000 seed weight were recorded in accordance with standard finger millet descriptors. The results obtained, showed that plant height in accession Ex-Kwi was significantly different from all the other nine accessions while the highest leaf length which was recorded in Ex-Riyom was significantly different (p < 0.05) from only accession Ex-Dantse. Similarly, significant variations were observed in the number and length of fingers, and 1000 seed weight across all the accessions tested, over the three cropping seasons in the multilocational trial. Evaluation of phenotypic and genotypic characters of the different accessions revealed that the genotypes expressed significant genetic diversity for plant height, 1000 seed weight, leaf length and number of tillers than all the other traits assessed at p < 0.05 level of significance. These results tend to suggest a high variability existing among the selected morphological traits. Specifically, 87% of the variations were explained by the ANOVA model leaving only 13% unexplained. The cluster analysis based on morphological traits revealed six major distinct groups with one landrace forming independent cluster for the pooled analysis for the three years.

The objective of this project was to evaluate ageing-induced genetic changes during storage of tomato seeds. Seeds of 10 accessions of tomatoes were thus subjected to artificial ageing in chambers conditioned to 55 °C and 72 ± 2% RH for 72 h. Seed survival data were used to estimate probit parameters. Genetic changes during the seed ageing course were evaluated by microsatellite (SSR) analysis using a Direct PCR™ kit., The SSR primer sequences (except SGN-14430) optimized the gene markers for the tomato accessions and are thus recommended for detecting genetic changes during seed storage. Genetic distances were calculated using PAST™ software and percentage genetic integrity was estimated from the genetic distance matrices. Probit analysis showed that P₅₀ estimates was least in accession LOO169 (7 days) and highest in accession 09/044 (64.4 days). Seeds having lower P₅₀ estimates showed lower estimates of genetic integrity. Lowest estimate of average genetic integrity was 99.21% when estimates of genetic distances were compared between 0 and 72 h of artificial ageing. The results showed ageing-induced genetic deterioration during artificial ageing thus suggests possibility of losses in genetic integrity of seeds in storage at a specific physiological (germinability) benchmark. For tomatoes, this study shows that seed germinability benchmark for genetic changes during ageing was approximately 42%. Comparison of tomato seeds stored in the NACGRAB gene bank for 2 years and freshly harvested seeds, validated the artificial seed ageing result and the estimated germination benchmark for declining genetic integrity in tomato seeds.

Introduced maize (Zea mays L.) germplasm can serve as important sources of favorable alleles for enhancing the performance of new maize varieties and hybrids under drought stress conditions. Ninety-six elite maize hybrids alongside four hybrid checks were evaluated for grain yield and other agronomic traits under managed stress conditions over two seasons at Ikenne, Nigeria. Hybrids differed significantly for grain yield and other measured traits under both drought stress and well-watered conditions. Grain yield varied from 444 to 3022 kg ha⁻¹ under drought stress, and from 3827 to 8887 kg ha⁻¹ under full irrigation. Drought stress reduced grain yield by 70%. Each of the top 10 yielders under drought stress produced >2500 kg ha⁻¹ and had a yield advantage of >10% over the best check. Three hybrids namely; ADL47 × EXL15, ADL41 × EXL15 and EXL02 × ADL47, produced competitive yields under both irrigation treatments.