Genotoxic and cytotoxic effects of food flavor enhancer, monosodium glutamate (MSG) using Allium cepa assay

Genotoxic and cytotoxic effects of monosodium glutamate (MSG) used as flavor enhancer in foods was analyzed using the Allium cepa assay. Onion bulbs were grown at different concentrations (1, 3, 5 and 7 g/L) of MSG dissolved in distilled boiled water and also evaluated when dissolved in distilled water without boiling; a control group was also set up. The macroscopic (morphology and color of roots) and microscopic (mitotic index and chromosomal aberrations) parameters of Allium root tips were studied. MSG inhibited growth of A. cepa root tips in all concentrations and was significant on days 2 to 5 in distilled water without boiling and on days three to five when dissolved in boiled distilled water. MSG also reduced the number of roots growing from primodium in all test concentrations as compared to control and the least was observed in 5 g and 7 g/L. Color of root tips range from brownish to dark brown or black in higher MSG concentrations. Sticky chromosomal aberration at telophase was most commonly induced in all the MSG test concentrations. MSG decreased mitotic index of A. cepa cells at all the test concentrations but this result was not statistically different. There was no significant difference in total chromosomal aberrations in all experimental set up as compared to control.Keywords: Monosodium glutamate, genotoxicity, cytotoxicity, Allium cepa assayAfrican Journal of Biotechnology Vol. 12(13), pp. 1459-146

Genetic diversity assessment and relationship among tropicalyellow endosperm maize inbred lines using SSR markers

Maize is the most important food crop in sub-Saharan Africa. Tropical-adapted yellow maize inbred lines can be used as source of provision of pro-vitamin A, needed by millions of African children that suffer from vitamin A deficiency. A substantial variation of pro-vitamin A content is known to exist among available inbred lines. The objective of this study was to assess the diversity and relationship among 38 tropical-adapted maize inbred lines. The lines were investigated using 87 SSR markers. Seventy-five (75) SSR markers were polymorphic across the 38 inbred lines and generated a total of 297 alleles. The polymorphic information content (PIC) values obtained for the polymorphic SSR markers varied from 0.17 to 0.84 with an average of 0.56 .The number of polymorphic alleles per locus ranged from 2 to 11 with a mean of 3.96. Genetic distance (GD) values among all pairs of inbred lines varied from 0.007 to 0.59 with an average of 0.45. Cluster and principal coordinate analyses based on genetic distance from SSR data showed two well defined main groups of the 38 inbred lines, consistent with their pedigrees. The study has revealed a considerable level of genetic diversity among the inbred lines. The genetic potential that exists will facilitate the selection of parents with diverse alleles for development of new maize genotypes with higher pro-vitamin A level

Genetic Analysis of Early White Quality Protein Maize Inbreds and Derived Hybrids under Low-Nitrogen and Combined Drought and Heat Stress Environments

An increase in the average global temperature and drought is anticipated in sub-Saharan Africa (SSA) as a result of climate change. Therefore, early white quality protein maize (QPM) hybrids with tolerance to combined drought and heat stress (CDHS) as well as low soil nitrogen (low-nitrogen) have the potential to mitigate the adverse effects of climate change. Ninety-six early QPM hybrids and four checks were evaluated in Nigeria for two years under CDHS, low-nitrogen, and in optimal environments. The objectives of this study were to determine the gene action conditioning grain yield, assess the performance of the early QPM inbred lines and identify high yielding and stable QPM hybrids under CDHS, low-nitrogen and optimal environment conditions. There was preponderance of the non-additive gene action over the additive in the inheritance of grain yield under CDHS environment conditions, while additive gene action was more important for grain yield in a low-nitrogen environment. TZEQI 6 was confirmed as an inbred tester under low N while TZEQI 113 × TZEQI 6 was identified as a single-cross tester under low-nitrogen environments. Plant and ear aspects were the primary contributors to grain yield under CDHS and low-nitrogen environments. TZEQI 6 × TZEQI 228 and the check TZEQI 39 × TZEQI 44 were the highest yielding under each stress environment and across environments. Hybrid TZEQI 210 × TZEQI 188 was the most stable across environments and should be tested on-farm and commercialized in SSA

Genome-Wide Association Analysis Reveals Genetic Architecture and Candidate Genes Associated with Grain Yield and Other Traits under Low Soil Nitrogen in Early-Maturing White Quality Protein Maize Inbred Lines

Maize production in the savannas of sub-Saharan Africa (SSA) is constrained by the low nitrogen in the soils. The identification of quantitative trait loci (QTL) conferring tolerance to low soil nitrogen (low-N) is crucial for the successful breeding of high-yielding QPM maize genotypes under low-N conditions. The objective of this study was to identify QTLs significantly associated with grain yield and other low-N tolerance-related traits under low-N. The phenotypic data of 140 early-maturing white quality protein maize (QPM) inbred lines were evaluated under low-N. The inbred lines were genotyped using 49,185 DArTseq markers, from which 7599 markers were filtered for population structure analysis and genome-wide association study (GWAS). The inbred lines were grouped into two major clusters based on the population structure analysis. The GWAS identified 24, 3, 10, and 3 significant SNPs respectively associated with grain yield, stay-green characteristic, and plant and ear aspects, under low-N. Sixteen SNP markers were physically located in proximity to 32 putative genes associated with grain yield, stay-green characteristic, and plant and ear aspects. The putative genes GRMZM2G127139, GRMZM5G848945, GRMZM2G031331, GRMZM2G003493, GRMZM2G067964, GRMZM2G180254, on chromosomes 1, 2, 8, and 10 were involved in cellular nitrogen assimilation and biosynthesis, normal plant growth and development, nitrogen assimilation, and disease resistance. Following the validation of the markers, the putative candidate genes and SNPs could be used as genomic markers for marker-assisted selection, to facilitate genetic gains for low-N tolerance in maize production