Yield of Assessraent Some Wheat Cultivars to Planting Date in Noorabad Mammasani

In order to determine the appropriate wheat sowing date in Mamasany, a field experiment was conducted in 2006-2007 as a factorial randomized complete block design with four replications. Three wheat cultivars (Chamran, Shiraz and Falat) were seeded at three rates of sowing date (11 Nov., 6 Dec and 31 Dec). Result showed that the effect of sowing date and cultivar on grain yield, biological yield and harvest index was statistically significant. The highest grain yield equal to 6168.33 kg ha-1 was obtained at 6 Dec sowing date increasing by 24% and 35% compared with the 11 Nov and 31 Dec sowing dates respectively. The biological yield and harvest index at 6 Dec sowing date equal to 13604.95 kg ha-1 and 45.33% were significantly higher than the other sowing dates. Also, every three yield components at 6 Dec sowing date were higher than the other sowing dates. The shiraz grain yield (5407.92 kg ha-1) was higher than that of Falat or. Chamran the biological yield, harvest index, number of spikes per squar meter and number of kernels per spike of Shiraz cultivar was higher compared to Falat and Chamran cultivars. The interaction of cultivars and sowing date on the grain yield was significant. The best sowing date was 6 Dec for Falat and Chamran cultivar and for Shiraz cultivar ranged from 11 Nov to 6 Dec. At 31 Dec sowing date, the grain yield of three cultivars was clearly decreased. Overall, early and late planting reduced grain yield.