effect of silicon and nitrogen different quantities on morphology characteristics, yield and yield components of two varieties of wheat

from the plants nutrition view point, silicon has not been recognized as an essential element but its useful effects on growth and development of many plants have been reported. in order to study the effect of application of different silicon on the yield component of wheat, an experiment was conducted in the city torbat heidarieh located in razavi khorasan province. the experiment was performed as a completely randomized design (crd) with factorial arrangement and four replications in green house condition. experimental factors include two wheat varieties (pishtaz and roshan), three levels of silicon (0, 250 and 500 mg/kg) from sodium silicate source and three levels of nitrogen (250, 500 and 800 mg/kg) from urea source. results showed that yield components (panicle weight, weight of 1000 grain, harvest index) significantly increased when silicon was applied to the soil. investigations have shown that lodging is an important factor for yield reduction, either directly or indirectly due to the appearance of some fungal diseases and also problems encountered at harvesting. silicon application increased the density of stem unit which may have positive effect an the resistance of plants to lodging. it was observed that silicon increased  plant height in a slow manner which is important for lodging. application of different nitrogen levels in the soil improved the efficiency of silicon uptake by the plant which shows the interaction between these two elements. treatments of 500 and 800 mg/kg silicon and nitrogen respectively increased the weight of 1000 grain and harvest index. application these  two elements respectively effect the performance of varieties of wheat yield. treatments of 500 mg/kg silicon performance of the highest yield. pishtaz and roshan varieties responded differently to silicon application. pishtaz responded better to growth characteristics and seems to have higher yield potential to roshan variety.