THE GENOTYPE-ENVIRONMENTAL INTERACTION ON YIELD AND ITS MAIN COMPONENTS OF BREAD WHEAT (Triticum aestivum L.)"

Abstract

        In order to evaluate the performance of ten wheat genotypes under low nitrogen conditions and to determine their ability to determine the optimal genotype for the appropriate environment. Three experiments were conducted during the winter season of 2021-2022 in three locations: Baghdad, Wasit, and Diwaniyah. The experiments were conducted according to the randomized complete block design with split plots arrangement, where nitrogen levels (0, 50, 100 kg N ha^-1) represented the main plots, while the genotypes(T2,T3,S1,S2,S148,IPA99, Adna99, Rasheed, Buhooth 10 and Buhooth22) represented the sub-plots with three replicates at each location. Aggregation analysis of the locations was performed. The results showed a genotype by environmental interaction between the genotypes and nitrogen fertilization levels. The S2(IPA95 X IPA99) genotype outperformed with the highest grain yield per unit area (5.38 t ha^-1) and did not differ significantly from Bahooth22 and IPA99 (5.37 and 5.26 t ha^-1, respectively) at the high nitrogen level (100 kg N ha^-1). These genotypes also outperformed at the low nitrogen level (50 kg N ha^-1). There was a significant interaction between genotypes and locations, as S2 had the highest grain yield (4.82 t ha^-1) in Baghdad. It is concluded that some genotypes performed well under low nitrogen stress conditions (50 kg N ha^-1), indicating that increasing nitrogen levels may not always result in a significant increase in yield. Furthermore, high-yielding genotypes showed adaptability to certain environments, suggesting that their qualitative traits should be studied to determine their response to environmental genetic interaction. Genotypes with baking quality may perform well in several environments and are not limited to a specific environment or lack baking quality.