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Adebayo M.A.,West Africa Center for Crop Improvement | Adebayo M.A.,International Institute Of Tropical Agriculture | Adebayo M.A.,Ladoke Akintola University of Technology | Menkir A.,International Institute Of Tropical Agriculture | And 5 more authors.
Journal of Crop Science and Biotechnology | Year: 2015

Knowledge about the genetic diversity within a germplasm allows for a more effective and efficient use of resources for crop improvement programs. Diversity assessment of 48 tropical drought-tolerant maize inbreds, 24 each from CIMMYT and IITA, was carried out with microsatellite markers to determine the genetic divergence between the two groups of maize inbred lines. Eighty-one polymorphic SSR markers were used for the assessment. Results showed that the average number of alleles per locus was 3.7. The mean polymorphic information content (PIC) was 0.51 whereas the average modified Roger's genetic distance (MRD) was 0.49. The mean genetic distance estimates between the CIMMYT and IITA lines were higher than the mean genetic distance among IITA lines or among CIMMYT lines. The average linkage cluster analysis separated the lines into two broad groups along institutional lines. The observed sub-groups within each main group were reflections of the relationships of the lines based on pedigree records. The F ST value of 19.5% reflects a high level of genetic differentiation between the two groups of lines. The results highlighted the presence of appreciable genetic divergence between CIMMYT and IITA lines that can be exploited for superior hybrid maize development. © 2015 Korean Society of Crop Science and Springer Science+Business Media Dordrecht.

Njoku D.N.,National Root Crops Research Institute NRCRI | Njoku D.N.,West Africa Center for Crop Improvement | Vernon G.,West Africa Center for Crop Improvement | Egesi C.N.,National Root Crops Research Institute NRCRI | And 6 more authors.
Journal of Crop Improvement | Year: 2011

This review presents an overview of the importance, constraints, and prospects on different aspects of cassava (Manihot esculenta crantz) breeding for enhanced micronutrient level, including carotenoids (precursors for provitamin-A) and especially beta-carotene. Early cassava-breeding efforts concentrated on crop yield, dry matter, and disease resistance, which are farmer-preferred traits. However, unacceptably high levels of preventable human diseases caused by malnutrition prompted breeders and nutritionists to screen wild relatives and unimproved germplasms (landraces) to increase micronutrient density in staple crops. The ultimate objective is to reduce diseases caused by micronutrient deficiencies. Nigeria, with 140 million people and the largest producer and consumer of cassava in the world, is characterized by rampant malnutrition and high incidence of nutrient deficiency-related diseases. The tuberous root of cassava is low in micronutrients. It is also well known that vitamin A deficiency is primarily caused by dietary inadequacy that results in progressive eye damage and eventually leads to blindness, especially in children. In addition, affected children suffer from a weakened immune system. Present interventions to eliminate this deficiency rely on supplementation and food fortification programs, do not reach all those affected and do not get to the root of the problem, which is an inadequate diet. The development of high micronutrient-content cassava varieties (especially, higher β-carotene and other carotenoids) will contribute to a more sustainable solution of the problem of vitamin A deficiency. A current thrust of research (HarvestPlus initiative) is to determine the genetic potential for increasing the concentrations of bioavailable Fe, Zn, and provitamin A carotenoids in the edible portions of several staple food crops including cassava, rice, wheat, maize, and beans. Currently, the International Institute of Tropical Agriculture (IITA), International Center for Tropical Agriculture (CIAT), and National Root Crops Research Institute (NRCRI), Umudike, are working in collaboration to develop an elite cassava gene pool and to develop varieties that will be released to farmers soon in hope of addressing part of micronutrient malnutrition. © Taylor & Francis Group, LLC.

Amissah J.N.,University of Ghana | Spiller M.,Leibniz University of Hanover | Oppong A.,University of Ghana | Osei-Safo D.,University of Ghana | And 4 more authors.
Journal of Applied Research on Medicinal and Aromatic Plants | Year: 2016

Cryptolepis sanguinolenta is a medicinal plant widely used in the treatment of malaria in Ghana. The increasing demand for its roots coupled with harvesting of the plant in non-sustainable ways has resulted in a substantial decline in its wild populations. The study was conducted to (1) determine the relatedness among C. sanguinolenta wild populations, (2) identify genotypes with high active ingredient (cryptolepine) concentrations and (3) understand the extent to which cryptolepine levels are influenced by soil. Root and stem samples for the study was collected from the Eastern, Ashanti, Brong Ahafo and Volta Regions of Ghana. C. sanguinolenta plants were found in sandy loam/sandy clay loam textured soils of acidic (4.3) to near neutral (6.7) pH ranges.Semi Quantitative Thin Layer Chromatography (SQ-TLC) and High Performance Liquid Chromatography (HPLC) methods were used to quantify the cryptolepine content in the stem and root samples. Cryptolepine concentrations in the stem and roots were not significantly influenced by location. No correlation was found between the soil properties studied and the cryptolepine content in the roots.Results from both SQ-TLC and HPLC analyses indicated that cryptolepine concentrations were on average, twice as much in the roots (0.84. mg/100. mg plant material) compared to the stem (0.42. mg/100. mg plant material).Results of the genetic diversity study showed a genetic diversity of 25% with genetic distances ranging between 0.08 and 0.14. Samples from the same location had the least genetic distances. Bootstrapping performed on the marker data and coefficient of variation calculated from distance resolutions obtained from 800 markers, proved to be of sufficient resolution. Sample sites did not reflect distinct sub-populations, a result of possible gene flow between sampling locations. Findings from this study will be useful for developing domestication protocols for C. sanguinolenta and subsequently the cultivation of elite genotypes. © 2015 Elsevier GmbH.

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