The study was carried out during 2017/2018 and 2018/2019 seasons at the Exp. Farm of Assiut University, to Evaluate 20 bread wheat genotypes (Triticum aestivum L) for traits related to lodging resistance and yield under different levels of nitrogen fertilization i.e. 50, 75 and 100 kg N/fed.
The results could be summarized as follow:
-   There were highly significant differences among the studied genotypes, levels of nitrogen and genotypes x nitrogen interaction traits related to lodging.
-   Plant height was positively and high significantly correlated with the second internode length under all nitrogen levels, while it was negatively highly significantly correlated with second internode diameter with an increase nitrogen levels.
-   The mean plant height and length of second internode over all genotypes increased as nitrogen rate increased up to 100 kg N/fed.
-   Increasing nitrogen rate up to 75 kg/fed. led to significant increase in the stem diameter, dry weight/unit and internode length. However, adding more nitrogen fertilizer showed negative effect on the above mentioned traits.
-   The lodging percentage increased with the increase of nitrogen rate. The causes of lodging differed from cultivar to another.
-   The grain yield significantly increased with the increase of nitrogen rate up to 100 kg/fed.

-   Results showed that the genotype Sakha 93 was the best for lodging percentage.