A field experiment at the Maize Research Station, General Authority of Agricultural Research in Abu-Ghriab, Iraq, began on six inbred lines of maize (1- UMGW 16, 2- UMGW 4, 3- DAQ, 4- HNG 9, 5- FAR 30, and 6- ABS – 32) as samples to generate 15 F1 single crossings through half-diallel cross. Crossing the parents and single crosses sought to produce 60 three-way cross hybrids. Grown seeds of three-way crosses became specimens to study the most effective traits that could affect the yield and become selective indicators to improve maize grain yield. The experiment proceeded as a randomized complete block design (RCBD) with three replicates. The analysis of variance results revealed statistically significant differences among all studied traits. The values of genetic variance were higher than the environmental variance for all studied traits except for plant height. The highest broad-sense heritability (0.956) appeared in grain yield per plant, followed by the days from planting to 50% silking (0.803). A significant positive genetic and phenotypic correlation was apparent between grain yield, 100-grain weight, and the number of grains per row, while a negative genetic correlation between grain yield and the number of days from planting to 50% silking occurred. The path analysis revealed that the number of grains per row has the highest positive direct effect (0.537) and the total of all effects (0.828). The number of grains per row gave the utmost indirect positive influence of 0.259 by the 100-grain weight.
Maize (Zea mays L.), genetic variability, path coefficient analysis, genotypic and phenotypic variances, broad-sense heritability, yield-related traits
Quantitative inheritance methods contribute to choosing the researcher’s direction toward selection or crossing between genotypes. Correlation and pathway analysis also helped in understanding the appropriate breeding method and which traits directly impact increasing the yield.