The Effect of Different Nitrogen Sources from Urea and Ammonium Sulfate on the Spikelet Number in Egyptian Spring Wheat Cultivars on Well Watered Pot Soils

Abstract: The spikelet number (SPN) is an important wheat yield component decided before anthesis. Our objective was to determine the effect of nitrogen (N) from urea and ammonium sulfate split-applied at different rates before anthesis on the SPN in the recent Egyptian cultivars Sakha93 and Sakha94 and two commonly used cultivars in pots. The response of SPN to applied N from ammonium sulfate was higher than that from urea in all four cultivars used. However, there was no difference in the responses of SPN to absorbed N from the two fertilizers in any of the cultivars. The SPN per applied and absorbed N was the highest in Sakha94 among the four cultivars. These cultivar differences in the SPN were due to the difference in the spike number. The results suggested that the N from ammonium sulfate has a greater effect on SPN than that from urea in recent Egyptian cultivars. Key words: Ammonium sulfate, Egyptian cultivars, Spike number, Spikelet number, Urea, Wheat. Wheat ( Triticum aestivum,