The effect of different sowing dates on yield and yield components of wheat (Triticum aestivum L.) cultivars.

Use of suitable cultivar and optimum planting time play an important role in getting the maximum yield of wheat crop. The study was conducted to find out the most suitable wheat cultivar and optimum planting time for dry and semi dry region. Experiment was carried out in a split-plot based on randomized complete bloke design with three replication at Kerman University, Iran, during 2010 growing season. Five sowing dates (6 October, 22 October, 6 November, 22 November and 6 December) were the main plots and six cultivars (Pishtaz, Roshan, Bam, Akbari, Arg and Sistan) were the sub-plots. Grain yield, plant height, number of tiller per plant, number of leaf per plant, number of spikes per plant, spike length, number of grain per spike, 1000 grain weight, biological yield and harvest index were investigated. According to the result, the effects of cultivar and sowing times on grain yield were found to be significant. The highest grain yield (4.84 ton ha) was obtained from cultivar Bam. On the other hand, the highest grain yields (4.9 ton ha) were obtained at the sowing times of 22 October. Correlations between grain yield and plant height, number of tiller per plant, number of head per plant, head length, number of grain per head, biological yield and harvesting index were positively significant. As a result, the period from 22 October to 6 December could be concluded as optimum sowing period for maximum grain yield for the region. Pishtaz cultivar should be preferred if the sowing time was late (6 December), But Roshan cultivar should be used early sowing (6 October).