Genetic Architecture of Grain Yield and Some of Its Components Traits in Maize (Zea mays L.)

Six inbred lines of maize (ZP-595, DKC-6418, DK-17, ZP-694, Sgporo from panan and UN 4652) were included in a half diallel cross. The inbred lines and their 15 crosses were planted in the fields of the College of Agricultural Engineering Sciences, Duhok University on July 5, 2018, using randomized complete block design with three replications. The components of phenotypic variance and narrow sense heritability were estimated, and the regression line analysis method was adopted for the traits: number of days to silking, number of days to tasseling, plant height, upper ear height, leaf area, number of rows. ear-1, number of grains. row-1, grain yield. Plant-1, weight of 300 grains, and shelling percent. The results showed that the mean square of the genotypes (parents and hybrids) was highly significant for all traits. The regression coefficient of Wr on Vr appeared significant for all traits except leaf area, indicating the presence of epistasis in its inheritance. It is also evident that the variances, additive (D) and dominant components (H1 and H2) were significant from zero for all traits, indicating the importance of additive and non-additive gene action in the inheritance of these traits. It was shown from Wr, Vr regression line analysis that the regression line cutting the Wr axis above the origin point for number of days to silking, number of days to tasseling, plant height, upper ear height, leaf area, number of rows. ear-1 and shelling percent, an indication of the additive effect of genes with a decrease in dominance, while the regression line crossed the Wr axis under the origin point, for number of grains. Ear-1, grain yield. Plant-1 and shelling percent indicating the presence of over dominance with proportions of dominant and recessive genes in parents. The narrow sense heritability was low for number of rows. ear-1, number of grains. Ear-1, grain yield. Plant-1, 300 grains weight and shelling percent, moderate for upper ear height and leaf area and high for number of days to silking, number of days to tasseling and plant height.