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. In future quality protein maize breeding efforts, special attention and emphasis should be given to yield and quality attributing characteristics in order to increase yield and quality features. In general, the findings of this study may be useful to researchers working to develop high-yielding varieties of high-quality protein maize for the mid-altitude environment.

Keywords: Correlation, Eigen Vectors, Eigenvalue, Heritability, genetic variability, genetic advance, Principal component analysis