BackgroundMolecular characterization is important for efficient utilization of germplasm and development of improved varieties. In the present study, we investigated the genetic purity, relatedness and population structure of 265 maize inbred lines from the Ethiopian Institute of Agricultural Research (EIAR), the International Maize and Wheat Improvement Centre (CIMMYT) and the International Institute of Tropical Agriculture (IITA) using 220,878 single nucleotide polymorphic (SNP) markers obtained using genotyping by sequencing (GBS).ResultsOnly 22% of the inbred lines were considered pure with <5% heterogeneity, while the remaining 78% of the inbred lines had a heterogeneity ranging from 5.1 to 31.5%. Pairwise genetic distances among the 265 inbred lines varied from 0.011 to 0.345, with 89% of the pairs falling between 0.301 and 0.345. Only <1% of the pairs had a genetic distance lower than 0.200, which included 14 pairs of sister lines that were nearly identical. Relative kinship analysis showed that the kinship coefficients for 59% of the pairs of lines was close to zero, which agrees with the genetic distance estimates. Principal coordinate analysis, discriminant analysis of principal components (DAPC) and the model-based population structure analysis consistently suggested the presence of three groups, which generally agreed with pedigree information (genetic background). Although not distinct enough, the SNP markers showed some level of separation between the two CIMMYT heterotic groups A and B established based on pedigree and combining ability information.ConclusionsThe high level of heterogeneity detected in most of the inbred lines suggested the requirement for purification or further inbreeding except those deliberately maintained at early inbreeding level. The genetic distance and relative kinship analysis clearly indicated the uniqueness of most of the inbred lines in the maize germplasm available for breeders in the mid-altitude maize breeding program of Ethiopia. Results from the present study facilitate the maize breeding work in Ethiopia and germplasm exchange among breeding programs in Africa. We suggest the incorporation of high density molecular marker information in future heterotic group assignments.Electronic supplementary materialThe online version of this article (10.1186/s12864-017-4173-9) contains supplementary material, which is available to authorized users.

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Biotic stresses are recently evolving very rapidly and posing significant yield losses of maize production in Ethiopia. A number of high yielding maize hybrids, initially developed as tolerant/resistant, have been taken out of production due to their susceptibility to major maize diseases. Furthermore, recent disease and insect pest epidemics have clearly shown the importance of breeding maize for biotic stresses and study the genetics of resistance to the major maize disease pathogens, insect pests and parasitic weeds. This paper gives the general perspective of the major biotic maize production stresses in Ethiopia and the interventions made locally and globally to control these stresses using host resistance. More emphasis was given to grey leaf spot (GLS), turcicum leaf blight (TLB), common leaf rust (CLR), maize streak disease (MSD), maize lethal necrosis (MLN), maize weevil, stalk borers, fall armyworm and Striga. Approaches to conducting genetic analysis and achieving durable host resistance to these stresses, where applicable, are discussed. This information will be used for breeders, private and public maize seed and grain growers who are targeting to operate in Ethiopia and Eastern Africa.

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To establish effective breeding techniques for the creation of nutritionally enhanced maize cultivars, reasonable information of the extent of genetic diversity, heritability, genetic advance, correlation analyses, and interrelationships of yield and yield related variables is essential. As a result, the goal of this study was to determine the nature and magnitude of genetic variability, heritability, Correlation Analysis, genetic advance, and principal Component analysis of grain yield and yield-related traits in quality protein maize inbred lines adapted to Ethiopia's mid-altitude agroecology. During 2019/2020, the experiment was done on 36 inbred lines, including four checks at Bako and Jimma. The genotypes were tested three times in an alpha lattice arrangement. For all parameters except days to maturity, the mean square due to genotypes was extremely significant, according to the analysis of variance. The level of phenotypic and genotypic variation among all eleven characteristics showed that the environment influenced the expression of features in some way. Grain yield, kernels per ear, ear diameter, and thousand kernels weight all showed a moderately greater heritability. The estimated genetic progress as a percent of mean for grain production, kernels per row, and ear per plant was extremely high, indicating the control of additive gene of action and a better hope for selection of these traits. Grain yield has a high heritability mixed with a high genetic advance, indicating that additive gene action is dominant in controlling the variable. Days to maturity, plant and ear height, ear diameter, ear per plant, and thousand kernel weights all exhibited extremely significant positive associations with grain yield. The eigenvalue of the first main component was 6.16, and it accounted for 4.60 of the total variances. The PC7 had large ear weights per plant, which most likely reflected yield. Finally, in future quality protein maize breeding efforts, special ......