Seed Yield and Yield Component of Some Spring Wheat Varieties as Affected by Different Sowing Dates in Neishabour

Highest seed yield of wheat can be produced when planting date coincides with suitable environmental condition for its growth and development. To study the yieldand yield components of some spring wheat varieties in different sowing dates, a field experiment was conducted in Neishabour during 2013-2015 cropping seasons, using a split plot experiment based on a randomized complete block design with three replications. Three sowing dates were October 11, November 10 and December 10 which were assigned to main plots and six sping wheat cultivars Chamran, Pishtaz, Bahar, Sirvan, Sivand and Parsi to the sub –plots. Results of combined analysis showed that sowing date had significant effect on the number of spikes per square meter, the number of seed per spike, number of days to heading, number of days to maturity, grain filling period, seed yield and harvest index. The highest and lowest seed yields were obtained from sowing date of the October 11 and December 10 respectively. Interaction between year and sowing date was significant for seed yield. Delaying the sowing date decreased seed yield for first and second year by 46% and 48% respectively. Mean seed yield of varieties for two years was 5649 kg.ha-1. The mean grain yield for first and second year were 6235 and 5064 kg.ha-1 respectively. The results of correlation analysis showed that the number of spike per square metter had the most effect on seed yield and yield components. In general, results revealed that highest yield for the varieties under study are sowing date of October 11. Parsi is the best one for this region, because is produced highest seed yield, number of spikes per meter squared LAI at anthesis.