To achieve a higher grain yield in wheat the matching of vegetative and reproductive stages of growth with the optimum environmental conditions, through a selection of appropriate planting date and rate, is crucial. The appropriate planting date and seeding rate for winter wheat cv. Shiraz under Shiraz enviromental conditions has not yet been studied in detail. The present experiment was conducted during 2001/2002 and 2002/2003 growing seasons at the Experimental Farm of Shiraz University, College of Agriculture located at Badjgah, using RCBD with a split plot layout of four replicates in either year. Main plots consisted of three planting dates (November 6th, December 6th and January 6th) while four planting densities (150, 250, 350 and 450 plants/m2) were chosen and layed out as sub plots. The results indicated that planting date significantly affected grain yield, number of grains per spike, number of spikes per m2 and 1000 grain weight, so that the highest grain yield was achieved for the second planting date(i.e. Dec. 6th) and a delay in sowing date was accompained by a significant decrease in grain yield. In the first sowing date, due apparently to coincidence of flowering with a period of low temperature, florets were not fertilized appropriately and hence the number of grain per spike was decreased significantly. In addition, the number of spikes per m2 , grains per spike and 1000 grain weight were significantly affected by planting densities, so that the highest number of spikes per m2 was obtained for the highest planting density (i.e. 450 plants/m2), however, the highest number of grains per spike and mean grain weight were obtained for the lowest planting density (i.e. 150 plants/m2). With increasing plant density, the number of spikes per m2 increased for all planting dates. Altogether, the results revealed that December 6th and 350 plants per m2 were the most appropriate planting date and rate for wheat (cv. Shiraz) under environmental conditions in Bajgah or under similar climatic conditions.
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