Melaku Gedil

International Institute of Tropical Agriculture | IITA · Bioscience Center

Vitamin A deficiency and its associated disorders are pervasive in sub‐Saharan Africa (SSA) including many middle‐ and low‐income countries across the world. Provitamin A‐enriched maize (Zea mays L.) inbred lines with desirable agronomic and adaptive traits have been developed and used to generate and commercialize maize varieties with medium to hi...

Micron3 nutrient deficiencies are pervasive in the diets of millions of people in developing countries, calling for effective mitigation measures. The development of biofortified cultivars through breeding holds promise for sustainable and affordable solutions to combat micronutrient deficiencies. Breeding efforts in the past decade have resulted i...

Background Using a desirable tester is considered one method used to maximise genetic differences among test crosses derived from new inbred lines and improves the overall performance of maize. Thus, this study aimed to evaluate the potency of the tester with varying levels of resistance to Striga hermonthica in determining the testcross performanc...

Drought represents a significant production challenge to maize farmers in West and Central Africa, causing substantial economic losses. Breeders at the International Institute of Tropical Agriculture have therefore been developing drought‐tolerant maize varieties to attain high grain yields in rainfed maize production zones. The present review prov...

Background The establishment of heterotic groups of inbred lines is crucial for hybrid maize breeding programs. Currently, there is no information on the heterotic patterns of the Provitamin A (PVA) inbred lines developed in the maize improvement program of the International Institute of Tropical Agriculture (IITA) to form productive PVA enriched h...

Maize is widely used for food, animal feed, and industrial raw material in Nigeria. This paper documents the important changes that characterize Nigeria's maize production and area expansion along with contributing factors that have transformed maize from a backyard food crop to a dominant food security and commercial crop. Using both secondary and...

Understanding the genetic relationships between the key founder inbred lines and derived inbred lines could provide insight into the breeding history and the structure of genetic diversity of the available elite inbred lines with desirable target traits. The maize improvement program at the International Institute of Tropical Agriculture (IITA) ana...

Maize is a major staple food in Sub-Saharan Africa (SSA). Vitamin A deficiency index is high in Africa and could be reduced through the consumption of provitamin-A-enriched maize. However, foliar diseases such as maize streak virus, northern corn leaf blight and common rust constrain maize production in SSA. The cultivation of host-resistant variet...

The parasitic weed, Striga is a major biological constraint to cereal production in sub-Saharan Africa (SSA) and threatens food and nutrition security. Two hundred and twenty-three (223) F2:3 mapping population involving individuals derived from TZdEI 352 x TZEI 916 were phenotyped for four Striga-adaptive traits and genotyped using the Diversity A...

Nitrogen deficiency is the most limiting abiotic stress factor affecting the grain yield of cowpea (Vigna unguiculata L.) in sub-Saharan Africa (SSA) countries. Breeding for high-yielding potential in association with high nitrogen fixation performance is the principal objective of cowpea breeding programs to improve both the productivity and produ...

Maize (Zea mays L.) is the most important staple food crop in sub-Saharan Africa (SSA). The parasitic weed, Striga hermonthica poses a major threat to maize production in the sub-region and can cause up to 100% yield loss. Striga siphons water and nutrients from the maize plant. During the past two decades, the IITA Maize Improvement Program has us...

Understanding genetic diversity is indispensable for conserving and utilizing the genetic resources of orphan crops. Information on cowpea genetic resource collections, and its characterization and conservation in Ethiopia is limited. The objectives of this study were to determine the extent of genetic diversity within cow-pea genotypes, assess the...

Yam (Dioscorea spp.) is an important crop providing food, income and medicine in tropics and subtropics. Major yam species in West Africa such as D. alata and D. rotundata are subject to several biotic and abiotic stresses throughout the cropping cycle and post-harvest periods, resulting in substantial tuber yield and quality trait losses. Abiotic...

Yam (Dioscorea spp.) is a major staple and cash crop in tropical and subtropical regions. However, biotic (fungus, viruses, tuber rots, nematodes, insects, etc.) and abiotic stresses (drought, low soil fertility, etc.) substantially impact the productivity and quality of yam crop in regions where it is majorly cultivated. Developing and deploying r...

Vitamin A deficiency poses health risks for children, pregnant women, and nursing mothers in sub-Saharan Africa (SSA) and Southeast Asia. Provitamin A–biofortified maize varieties can contribute to minimizing the adverse effects of vitamin A deficiency in areas where maize is a staple food crop. Identifying suitable testers is important to breed pr...

Background: Molecular breeding is an essential tool for accelerating genetic gain in crop improvement towards meeting the need to feed an ever-growing world population. Establishing low-cost, flexible genotyping platforms in small, public and regional laboratories can stimulate the application of molecular breeding in developing countries. These la...

Background Temperate maize inbred lines with expired Plant Variety Protection Act certificates (Ex-PVP) are potential sources of desirable alleles for tropical germplasm improvement. Up to now, the usefulness of the Ex-PVP inbred lines as a potential source of novel beneficial alleles for Striga hermonthica resistance breeding to enhance genetic ga...

Background: Molecular breeding is an essential tool for accelerating genetic gain in crop improvement, towards meeting the need to feed an ever-growing world population. Establishing low-cost, flexible genotyping platforms in small, public and regional laboratories can stimulate the application of molecular breeding in developing countries. These l...

Cowpea is one of the most important indigenous food and forage legumes in Africa. It serves as a primary source of protein for poor farmers in drought-prone areas of Ethiopia. The crop is used as a source of food, and insurance crop during the dry season. Cowpea is adaptable to a wide range of climatic conditions. Despite this, the yield of the cro...

Background: Molecular breeding is an essential tool for accelerating genetic gain in crop improvement, towards meeting the need to feed an ever-growing world population. Establishing low-cost, flexible genotyping platforms in small, public and regional laboratories can stimulate the application of molecular breeding in developing countries. These l...

Striga hermonthica is a widespread, destructive parasitic plant that causes substantial yield loss to maize productivity in sub-Saharan Africa. Under severe Striga infestation, yield losses can range from 60 to 100% resulting in abandonment of farmers' lands. Diverse methods have been proposed for Striga management; however, host plant resistance i...

Striga hermonthica is a widespread, destructive parasitic plant that causes substantial yield loss to maize productivity in sub-Saharan Africa. Under severe Striga infestation, yield losses can range from 60 to 100% resulting in abandonment of farmers’ lands. Diverse methods have been proposed for Striga management; however, host plant resistance i...

Cowpea is one of the most important indigenous food and forage legumes in Africa. It serves as a primary source of protein for poor farmers in drought-prone areas of Ethiopia. The crop is used as a source of food, and insurance crop during the dry season. Cowpea is adaptable to a wide range of climatic conditions. Despite this, the productivity of...

The development of maize varieties with increased concentration of Provitamin A (PVA) is an effective and affordable strategy to combat vitamin A deficiency in developing nations. However, the considerably high cost of carotene analysis poses a major challenge for maize PVA biofortification, prompting the use of marker-assisted selection. Presently...

Identifying efficient testers for separating maize (Zea mays L.) inbred lines into heterotic groups can facilitate the development of superior hybrids. Striga-resistant yellow-maize inbred lines developed at the International Institute of Tropical Agriculture (IITA) do not have well established heterotic groups. This study was conducted to identify...

Provitamin A enrichment of staple crops through biofortification breeding is a powerful approach to mitigate the public health problem of vitamin A deficiency in developing countries. Twenty-four genetically diverse yellow and orange endosperm maize inbred lines with differing levels of provitamin A content were used for the analysis of their combi...

Provitamin A-enriched maize (Zea mays L.) is an important complementary food staple for combating vitamin A deficiency (VAD) in high maize-producing and maize-consuming countries of sub-Saharan Africa (SSA). However, frequent drought is a major abiotic factor that retards maize growth, resulting in yearly fluctuations in grain yield. Development of...

Most of the maize (Zea mays L.) varieties in developing countries have low content of micronutrients including vitamin A. As a result, people who are largely dependent on cereal-based diets suffer from health challenges due to micronutrient deficiencies. Marker assisted recurrent selection (MARS), which increases the frequency of favorable alleles...

Identification of testers is crucial for hybrid maize breeding programme. However, limited information is available about ideal testers for characterising the combining ability of Striga resistant maize inbreds. This study was conducted to assess the relative value of three inbred testers with varying resistance reactions to Striga for determining...

A desirable tester that elicits greater genetic difference in Striga resistance among test crosses in a breeding program has not been reported. Therefore, this study was conducted to characterize 30 Striga resistant yellow endosperm maize inbred lines and three testers with varying resistance levels to Striga using DArTseq SNP markers and agronomic...

A hemiparasitic plant, Striga hermonthica (Del.) Benth and soil nitrogen stress are the key constraints to maize (Zea mays L.) productivity in sub-Saharan Africa, where commonly cultivated maize is the normal endosperm type that is deficient in provitamin A, tryptophan and lysine (PVATL). Seventy-six extra-early maize inbreds with provitamin A, try...

Soybean productivity in sub-Saharan Africa (SSA) is less than half of the global average yield. To plug the productivity gap, further improvement in grain yield must be attained by enhancing the genetic potential of new cultivars that depends on the genetic diversity of the parents. Hence, our aim was to assess genetic diversity and population stru...

Soybean ( Glycine max (L.) Merr.) is an important legume crop with high commercial value widely cultivated globally. Thus, the genetic characterization of the existing soybean germplasm will provide useful information for enhanced conservation, improvement and future utilization. This study aimed to assess the extent of genetic diversity of soybean...

Background Assessment and effective utilization of genetic diversity in breeding programs is crucial for sustainable genetic improvement and rapid adaptation to changing breeding objectives. During the past two decades, the commercialization of the early and extra-early maturing cultivars has contributed to rapid expansion of maize into different a...

Maize streak virus (MSV) is responsible for streak disease of maize and poses a serious threat to maize production in sub-Saharan Africa. Polygenic resistance to MSV has become an essential requirement in modern maize cultivars to mitigate yield losses. Many single nucleotide polymorphism (SNP) markers linked to putative MSV resistance loci have be...

Low soil nitrogen (low-N) and stem borer attack are two of the major stresses limiting maize production in West and Central Africa (WCA). Thus, there is need to intensify efforts aimed at identifying inbred lines with resistance and tolerance to these stresses for hybrid development. The objectives of the study were to determine the combining abili...

Background Molecular breeding has been recognized as one of the pillars to accelerate the rate of genetic gain in crop improvement towards meeting the need to feed an ever-growing world population. Establishing low-cost and flexible genotyping platforms in small and public laboratories and regionally can stimulate the application of molecular breed...

Both cowpea and yard-long bean belong to Vigna unguiculata ssp. unguiculata but have diverged through human induced evolution in sub-Saharan Africa and Asia, respectively. To map the quantitative trait loci (QTLs) for yield associated traits and derive new lines that may combine the attributes of both types, we developed a F2:3 mapping population d...

Vitamin A deficiency (VAD) is a serious problem in sub-Saharan Africa (SSA) and other parts of the world. Understanding the effect of marker-based improvement (MARS) of two maize synthetics (HGA and HGB) representing different heterotic groups on their agronomic performance, carotenoid content, and combining abilities could help identify suitable s...

Strigahermonthica (Del.) Benth is a parasitic weed that devastates cereals in Sub-Saharan Africa. Several control measures have been proposed for the parasite, of these, host plant resistance is considered the most cost-effective for poor farmers. Some tolerant/resistant lines have been developed and these lines display tolerance/resistance mechani...

Accurate estimation of genetic variability present in tropical maize inbreds with varying reactions to Striga hermonthica infestation is essential for efficient and sustainable utilization to ensure increased genetic gain in a breeding program. Thirty-six early maturing maize inbred lines and 156 single cross hybrids were evaluated under Striga-inf...

Striga hermonthica is a serious biotic stress limiting maize production in sub-Saharan Africa. The limited information on the patterns of genetic diversity among maize inbred lines derived from source germplasm with mixed genetic backgrounds limits the development of inbred lines, hybrids, and synthetics with durable resistance to S. hermonthica. T...

Striga is an important biotic factor limiting maize production in sub-Saharan Africa and can cause yield losses as high as 100%. Marker-assisted selection (MAS) approaches hold a great potential for improving Striga resistance but requires identification and use of markers associated with Striga resistance for adequate genetic gains from selection....

Genetic adaptation of maize to the increasingly unpredictable climatic conditions is an essential prerequisite for achievement of food security and sustainable development goals in sub-Saharan Africa. The landraces of maize; which have not served as sources of improved germplasm; are invaluable sources of novel genetic variability crucial for achie...

Breeding efforts in West and Central Africa (WCA) have focused on the development of Low‐N‐tolerant (LNT) maize inbreds and their classification into heterotic groups. This study was conducted to classify LNT maize lines into heterotic groups using testcross performance, morphological and SNP markers and to compare the consistency of groupings by t...

The choice of an appropriate tester is important for success in resistance hybrid breeding programs. Limited information is available on the most suitable testers that allow the selection of yellow endosperm maize inbred lines with good combining ability for resistance to witchweed (Striga hermonthica) and superior agronomic performance in hybrids...

Striga hermonthica parasitism is a major constraint to maize production in sub-Saharan Africa with yield losses reaching 100% under severe infestation. The application of marker-assisted selection is highly promising for accelerating breeding for Striga resistance/tolerance in maize but requires the identification of quantitative trait loci (QTLs)...

Background: Striga hermonthica (Benth.) parasitism militates against increased maize production and productivity in savannas of sub-Saharan Africa (SSA). Identification of Striga resistance genes is important in developing genotypes with durable resistance. So far, there is only one report on the existence of QTL for Striga resistance on chromosom...

Maize streak virus (MSV) continues to be a major biotic constraint for maize production throughout Africa. Concerning the quantitative nature of inheritance of resistance to MSV disease (MSVD), we sought to identify new loci for MSV resistance in maize using F2:3 population. The mapping population was artificially inoculated with viruliferous leafh...

Maize production in West and Central Africa (WCA) is constrained by a wide range of interacting stresses that keep productivity below potential yields. Among the many problems afflicting maize production in WCA, drought, foliar diseases, and parasitic weeds are the most critical. Several decades of efforts devoted to the genetic improvement of maiz...

p>The study aimed at examining the associations between yield and other traits under drought stress and non-stress conditions. A total of 150 MARS testcrosses were evaluated under both conditions at the International Institute of Tropical Agriculture substation for two years under during the dry season. Genotypic and phenotypic correlation, multipl...

Dioecy (distinct male and female individuals) and scarce to non-flowering are common features of cultivated yam (Dioscorea spp.). However, the molecular mechanisms underlying flowering and sex determination in Dioscorea are largely unknown. We conducted SuperSAGE transcriptome profiling of male, female and monoecious individuals to identify floweri...

Ethiop. J. Agric. Sci. 29(3)89-104 (2019) Genetic Diversity of Ethiopian Cowpea [Vigna unguiculata (L) Walp] Genotypes Using Multivariate Analyses Tesfaye Walle 1*, Firew Mekbib2, Berhanu Amsalu3 and Melaku Gedil4 1Department of Plant Sciences, Wolkite University, Wolkite, Ethiopia; 2School of Plant Sciences, Haramaya University, Dire Dawa, Ethi...