Genetic Stability of Different Genotypes of Bread Wheat (Triticum aestivum L.) Grown Under Levels of Nitrogen Fertilizer

Abstract

Obtaining highly productive and stable varieties through different environments is one of the most important goals sought by plant breeders. A field experiment was carried out to investigate the effect of different nitrogen fertilizer levels on the stability of growth and grain yield in eight cultivars of bread wheat during two growing seasons (2020-2021 and 2021-2022), using split plot arrangement in randomized complete block design (RCBD) with three replications. The results showed that there was a significant response of some genotypes to the levels of nitrogen fertilizer for grain yield and its components during the two growing seasons. The Iba99 genotype was characterized by the highest mean of grain yield, number of grains. spike-1 and spike length, followed by the Baghdad2 genotype. The genotypes under study differed in the stability of traits in different environments. Baghdad2 showed the highest stability for important traits such as grain yield, weight of 1000 grains, number of grains spike-1 and spike length, while unstable and responded to different environments for plant height and a number of spikes.m-2. Whereas, Iba99 showed good stability for the spike length and the number of spikes.m-2, with its response to the environments for the other traits under study. Both stability phenotypic and genotypic resultant method and the stability triangle method showed very similar results with Eberhart and Russell method, therefore it is possible to rely on these two methods to estimate the stability of genotypes due to their lower complexity. Consequently, the stable genotypes traits in different environments can be selected and introduced directly into future breeding programs for the purpose of adopting new varieties. Although other genotypes showed superior characteristics of grain yield and its important components, they suffer by responding to different environments, thus they can be included in hybridization breeding programs with local varieties to transfer their desirable traits.