Genetic Parameters Estimates Through Line × Tester Analysis for the Stay Green, Yield and Quality in Maize (Zea mays L.).

Abstract

A field experiment was carried out in the Anbar governorate-Ramadi, located at longitude 043.26 and latitude 033.43 for the fall season 2019 and spring season 2020. Seven inbred lines were crossed with three testers using line × tester mating design to produce 21 single hybrids, the resulting 21 crosses along with ten parents were evaluated during autumn 2019 and spring 2020 in a complete randomized block design with three replications. The objectives of this study were to determine gene action, some genetic parameters, and general (GCA), specific combining ability (SCA). The results showed significant differences between the parents and their crosses in all traits. The Inb23 strain outperformed the average individual plant yield, reaching 138.32 g, and the Inb17 × AGR21 hybrid gave the highest mean plant yield 198.28 g, the ZP607 tester gave the highest positive effect for general combining ability in plant yield of 3.097. The components of the variance of the special combining ability were greater than the components of the variance of the general combining ability, and the dominance genetic variance was more important than the additive genetic variance. The narrow sense heritability was low for the number of grains ear and the yield, and was highest in the weight of 300 grains and the number of effective leaves was 14.27% and 13.44%, respectively, resulting in a higher average degree of dominance values more than one for all traits. It is concluded from the study the possibility of using some of the superior parents in their crosses to derive individual hybrids with a specific combine ability to produce high grain yield because most of their characteristics were under the influence of dominance and overdominance, and it is possible to use the character of the number of effective leaves as an selection index to increase the yield.