Canola sensitivity to delayed sowing date should be managed in such a way that the observance of crop rotation with less reduced in seed yield. The research was conducted to evaluate the yield variation of Hyola401 hybrid, affected by sowing date and nitrogen fertilizer treatments. In this study, the effect of planting date and different levels of nitrogen fertilizers on effective characteristics of canola yield were carried out by combined analysis split plot experiment based on randomized complete blocks design in two consecutive years with four replication. Main plot included different planting date (10-Nov, 20-Nov, 1-Dec, 10-Dec.) and four level of nitrogen fertilizers (0, 50, 100, 150, 200 kg.ha-1) belonged to sub plots. The results indicated that canola yield affected by planting date, is subject the linear relationship Y= 2693.0-36.05D (Y= yield and D=planting dates) so crop yield 3.1% decreased per each day delay in planting date. Canola yield in different level of nitrogen treatments was subjected non-liner relation Y=1360.5-0.17N2-0.00063N3 accordingly, most efficiency in the treatment of 100 and 150 kg of nitrogen fertilizer were found. Estimate yield affected by planting date and nitrogen fertilizer based on the relation Y= 1654-36.1D + 10.4N indicated per every day the sowing is delayed about 36.1 kg of seed yield reduction occurs, so to compensate mentioned reduction in the range of studied planting date about 10.4 kg of nitrogen fertilizer should be consumed. Determining the correlation coefficient between yield and its components by using interaction effect of sowing date and nitrogen fertilizer revealed that the number of pods per plants and seed weight had more correlation with the seed yield trait, which is indicated significant effect of the implemented treatments on these two components of yield. Manuscript profile

BACKGROUND: Knowing about seed yield and its components plays an important role for being successful in evaluative programs. For optimization of crop production, sowing at the appropriate time to fit the cultivar maturity length and growing season is critical. OBJECTIVES: Current study was done to assess the effect of different planting date and density on seed yield, its components and harvest index of breed Wheat. METHODS: This research was carried out via split plot experiment based on randomized complete blocks design with three replications. The treatments included four planting dates (November 6th and 21st, December 6th and 21st) and different density (300, 400, 500, 600 and 700 seed per square meter). RESULT: According result of analysis of variance effect of planting date, density and interaction effect of treatments on all measured traits (instead number of seed per spikelet) was significant. Delay in planting caused the number of spikes per m2, number of seeds per spike, 1000-seed weight and seed yield from 493.3 spikes, 46.2 seeds, 32.2 grams and 6964 kg.ha-1 on the planting date of 30 November to 493.3 spikes, 40 seeds, 28.5 grams, 4831.6 kg.ha-1 should be reduced on 30 December. Assessment mean comparison result of interaction effect of treatments indicated maximum seed yield (7298.7 kg.ha-1) was noted for 6 Nov. and 500 plant per m2 and lowest one (4235.2 kg.ha-1) belonged to 6 Dec. and 700 plant per m2 treatment. CONCLUSION: Generally based on result of current research planting date in domain sixth until twenty-first of November with density of 500 plants per m2 had the highest crop production and it can advise to farmers under studied region. Manuscript profile