Variation among cassava (Manihot esculenta Crantz) genotypes for storage root yield, yield components and response to cassava mosaic disease at the advanced breeding stage

Cassava is a crucial starchy root crop cultivated worldwide in tropical and subtropical areas. Efforts have been made to improve its desirable characteristics to increase food and nutritional quality. However, the adoption of new cassava varieties can be influenced by their yield performance, which can be affected by cassava mosaic disease (CMD). The present study evaluated selected cassava genotypes' performance across two years at the advanced breeding stage. Using a randomized complete block design with two replications, 16 genotypes, a yellow root variety (TMS07/0593) and a white root (TMS30572) as checks were evaluated for yield, yield-related traits and response to CMD. There were highly significant (P < 0.001) variations among the cassava genotypes for yield-related traits, but no genetic variation was reported for fresh and dry root yields. The effect of season and genotypes × season interaction on all traits was significant only for harvest index and percentage of survival plants, respectively. Only genotype UIC-17-2428 and the two national check varieties (TMS07/0593 and TMS30572) did not resist CMD completely. At harvest, genotype UIC-17-2031 had the highest fresh root yield (39.0 t/ha), dry root yield (10.5 t/ha), and harvest index (0.63). Genotype UIC-17-58 had the highest dry matter content (37.2%) at harvesting, followed by UIC-17-46 (36.4%) while genotype UIC-17-583 had the lowest value (22.8%). The genotypes evaluated have promising premium agronomic traits. To assess their stability, genotypes with outstanding dry root yield must be evaluated across multiple environments.

Performance of testers with contrasting provitamin A content to evaluate provitamin A maize for resistance to Aspergillus flavus infection and aflatoxin production

Open Access JournalIn sub-Saharan Africa (SSA), millions of people depend on maize as a primary staple. However, maize consumers in SSA may be exposed to malnutrition due to vitamin A deficiency (VAD) and unsafe aflatoxin levels, which can lead to serious economic and public health problems. Provitamin A (PVA) biofortified maize has been developed to alleviate VAD and may have additional benefits such as reduced aflatoxin contamination. In this study, maize inbred testers with contrasting PVA content in grain were used to identify inbred lines with desirable combining ability for breeding to enhance their level of resistance to aflatoxin. Kernels of 120 PVA hybrids generated by crossing 60 PVA inbreds with varying levels of PVA (5.4 to 51.7 µg/g) and two testers (low and high PVA, 14.4 and 25.0 µg/g, respectively) were inoculated with a highly toxigenic strain of Aspergillus flavus. Aflatoxin had a negative genetic correlation with β-carotene (r = −0.29, p 0.5). Eight inbreds had combined significant negative GCA effects for aflatoxin accumulation and spore count with significant positive GCA effects for PVA. Five testcrosses had combined significant negative SCA effects for aflatoxin with significant positive SCA effects for PVA. The high PVA tester had significant negative GCA effects for aflatoxin, lutein, β-carotene, and PVA. The study identified lines that can be used as parents to develop superior hybrids with high PVA and reduced aflatoxin accumulation. Overall, the results point out the importance of testers in maize breeding programs to develop materials that can contribute to controlling aflatoxin contamination and reducing VAD

Validation of KASP-SNP markers in cassava germplasm for marker-assisted selection of increased carotenoid content and dry matter content

Open Access Journal; Published online: 12 Oct 2022Provitamin A biofortification and increased dry matter content are important breeding targets in cassava improvement programs worldwide. Biofortified varieties contribute to the alleviation of provitamin A deficiency, a leading cause of preventable blindness common among pre-school children and pregnant women in developing countries particularly Africa. Dry matter content is a major component of dry yield and thus underlies overall variety performance and acceptability by growers, processors, and consumers. Single nucleotide polymorphism (SNP) markers linked to these traits have recently been discovered through several genome-wide association studies but have not been deployed for routine marker-assisted selection (MAS). This is due to the lack of useful information on markers’ performances in diverse genetic backgrounds. To overcome this bottleneck, technical and biological validation of the loci associated with increased carotenoid content and dry matter content were carried out using populations independent of the marker discovery population. In the present study, seven previously identified markers for these traits were converted to a robust set of uniplex allele-specific polymerase chain reaction (PCR) assays and validated in two independent pre-breeding and breeding populations. These assays were efficient in discriminating marker genotypic classes and had an average call rate greater than 98%. A high correlation was observed between the predicted and observed carotenoid content as inferred by root yellowness intensity in the breeding (r = 0.92) and pre-breeding (r = 0.95) populations. On the other hand, dry matter content-markers had moderately low predictive accuracy in both populations (r< 0.40) due to the more quantitative nature of the trait. This work confirmed the markers’ effectiveness in multiple backgrounds, therefore, further strengthening their value in cassava biofortification to ensure nutritional security as well as dry matter content productivity. Our study provides a framework to guide future marker validation, thus leading to the more routine use of markers in MAS in cassava improvement programs

Williamson-hall analysis and absorption spectrum fitting in the estimation of crystallite size and band gap energy of CdZnS thin films

CdZnS ternary thin film was successfully prepared from cadmium sulphide (CdS)/zinc sulphide (ZnS) bilayer and its subsequent post thermal annealing via chemical bath technique. X-ray diffraction measurement indicates that the samples presented a crystalline wurtzite phase with (002) plane as the preferred orientation. Williamson-Hall (W-H) analysis was employed to estimate the crystallite size and the microstrain. The result showed that the crystallite size decreases with increasing ZnS layer deposition times. Using the Tauc model, the absorption spectrum fitting (ASF) procedure was used to determine the optical band gap energy. The values of the band gap energy range between 3.61 and 3.66 eV, with the values increasing with ZnS layer deposition times

Auditors’ Usage of Computer-Assisted Audit Techniques (CAATs): Challenges and Opportunities

International audienceThe objectives of this research is to give a clear view of the electronic auditing environment in companies, to determine the main benefits and challenges of Computer Assisted Audit Techniques (CAATs) and to review the opinions of researchers on Generalized Audit Software (GAS). The study also sheds the light on the reality of electronic auditing in Kingdom of Bahrain. The descriptive approach was used, where the previous studies were surveyed, discussed accurately, and then the results of the study were reached. The results showed the benefits and challenges of evolving from traditional audit techniques to CAATs. This research provides more detailed information about the use of GAS in the different sectors of companies. It also provides academic contribution not only in auditing area but also in information technology, especially in Bahrain. At the end of the study, there are suggestions for future research, which may help to get a qualitative achievement in the use of electronic audit and CAATs in Bahrain

Effects of demographic factors on bank customers' attitudes and intention toward Internet banking adoption in a major developing African country

This study provides an African perspective to the global research and literature on retail customer adoption of Internet banking (IB). It empirically examines the influence of seven demographic variables – age, gender, level of education, marital status, employment status, income level and area of residence – on retail banking customers' behaviours toward IB adoption in a major developing African country – Nigeria. A sample of 500 customers was surveyed, and ANOVA and multiple regression analyses were used in testing the association of the variables with customer attitude and intention toward IB adoption. Although all seven variables were correlated with attitude and intention, only gender, level of education, and employment status showed significant ability to influence Nigerian customers' attitude and intention toward IB adoption. The study therefore concludes that gender, level of education, and employment status are the major demographic affecters of Nigerian banking customers' attitudes to IB adoption