Two field trials were conducted at Shandaweel Agricultural Experimental
Research Station during two Successive seasons of 2002/2003 and 2003/2004. The
objectives of this study was conducted study to study the effect of two sowing dates         (normal and late planting) and four nitrogen fertilizer rates(25,50,75 and 100kgN/fed)                  , on six durum wheat genotypes, i.e. Sohag 1, Sohag 2, Sohag 3, Bani-Sweif 1, Bani- Sweif 2, Bani-Sweif 3. The results showed that means of squares of all the studied traits, were significant in the recommended sowing date compared to the late planting. Number of days to heading decreased when the sowing date was delayed. The earliest genotype for heading date was Sohag 1, while the genotype Bani-Sweif 3 was the latest for this trait. The recommended sowing date produced the highest number of spike/m2, number of kernels/spike, 1000-kernel weight, biological yield and grain yield/m2. Genotype Sohag 3 gave the highest number of kernels/spike, while the great value of number of spikes/ m2 and grain yield was obtained by Bani-Sweif
3genotype . Heading date, number of spikes 1m2, number of kernels/spike, 1000- kernel weight, biological and grain yield-/ha were increased with the increments of nitrogen application levels up to 100kgN/fed. However, the results obtained from the plants supplied with 75kgN/fed except number of spikes/m2 up to 50kgN/fed were not
significant different from those provided with 100kgN/fed. The interaction between sowing date and cultivars had significant effect for
all the studied traits. However, the interaction between sowing dates and nitrogen
fertilizer levels significant for heading date, biological yield and grain yield/ha, The
interaction between genotypes and nitrogen fertilizer levels had a significant effect for
heading date and grain yield. Furthermore, the interaction between sowing date,
genotypes and nitrogen fertilizer levels was significant for number of kernels per spike,
biological and grain yield.lha Therefore, the conclusion of this study is that executing breeding program on
the preceding wheat genotypes as well as adopting the proper agricultural practices in
Upper Egypt such as planting in a proper time, and adding 75kgN/fed, in particular, at
the first stage of the growth of wheat plants in a season could improve and increase
both grain yield of wheat plants and its components in Upper Egypt.