Field experiments were carried out on the clay soil of the Experimental Farm, Faculty of Agriculture, Assiut University, Assiut in two consecutive winter seasons 2007-2008 and 2008-2009. The aim of this investigation was to study the effects of three planting dates and three seeding rates in cv. Giza 6 on yield and quality of onion sets under Assiut conditions.
The obtained results indicated that the minimum average plant length was recorded for January 1st planting, and maximum plant length was found with planting on November 1st in both seasons and sampling dates. Sowing rate of 30 kg/fed of onion seeds gave significantly the tallest onion plants. Average bulb diameter increased significantly with earlier planting compared with later planting. Lower seeding rate gave significantly the biggest average bulb diameter. The authenticity bulb was obtained from planting on December 1st in the second sampling date (105 days). However, no true bulb was obtained from any planting date in the first sampling date (75 days) in both seasons. Lower seed rate (30 kg/feddan) significantly gave the truth bulb in both seasons.