Genetic Analysis of Diallel Crosses Between Five Moderately Maturing Inbred Lines of Maize

Abstract

This study was conducted during the spring season of 2008 at the Farm of the College of Agriculture -Duhok University, Iraq by using five maize inbred lines locally developed. Half diallel cross design was applied for these inbred lines to produce ten F 1 single crosses. A yield trial for the 10 hybrids and their parents was carried out in the Research Farm of the College of Agriculture Salahaddin University, Iraq using a randomized complete block design with three replications in order to study the gene action for yield and yield components beside estimating heterosis, combining ability and variance components (additive, dominance and environmental variance) in addition to estimate some other genetic parameters. The results showed the presence of significant differences among genotypes for all characters. For mean grain yield the best parent was (ZP -197), while the best hybrid was (ZP -707 × DK). The parent (ZP -595) appeared to be the best general combiner for most studied characters, while the hybrid (ZP -607) × (ZP -707) appeared to be the best for specific combining ability. Ratio of general to specific combining ability variances was more than one for all characters, indicating that the characters were under the effect of over dominance. Broad sense heritability value was found to be high in all the studied characters, while the narrow sense heritability was moderate for silking and tasselling date, grain yield / plant, number of kernels / row , 100-kernel weight and low for plant height , ear height , leaf area , number of rows / ear, ear length and number of kernels / ear. The expected genetic advance from selection was high for grain yield / plant and 100-kernel weight. The hybrids (DK × ZP-197) and (ZP -707 × ZP -197) gave the highest heterosis value in silking and tasselling date, while the heterosis value was high for the flag leaf area, ear height and grain yield / plant and was low for kernels / row , rows / ear, ear length and 100-kernel weight with different hybrids.