Abstract :
Delay in planting and low precipitation ( < 300mm annual) in wheat (Triticum aestivum L.) farming is the major problem in the irrigated and rainfall lands of Iran. A factorial experiment for evaluating the effects of seed priming on wheat cultivars was carried out under laboratory, greenhouse and at two field conditions during seasons of 2008-2010. Arrangement of treatments were Zarrin, Shariar, Sardary and Azar cultivars as A factor, and priming treatments including DW, osmotic solutions (10% PEG, 2.5% KCl, 4% MN, 10% Urea, 5% NaCl W/V) and plant growth inducers (20ppm IAA, 1000ppm CCC) with non-primed seed as a control established B factor. At the second year of field conditions two separate experiments were done under drought stress and well watered conditions. Irrigation of drought stress was withheld at booting stage. Maximum amount of absorbed water was related to Shariar, which was 15.5 g at DW. At all cultivars the most increased seed weight was seen for primed seed with CCC and IAA. Irrespective of cultivar seedling related traits revealed that CCC increased plumule and their radical dry weights (11.5 and 8.0mg) and lengths (17.2 and 17.8cm). In opposite, Urea pretreatment had negative effects for seedling growth. All priming treatments at four cultivars increased grain yield and its components, chlorophyll content and nitrogen absorbed under field and green house conditions than control. Primed seed with potassium chloride at drought stress had the low variation percentage for traits of relative water content (-9.3%), total dry matter (-10.7%) and grain yield (-4.0%) than well watered conditions. Potassium chloride improved drought tolerance at all wheat cultivars. There were significant correlations for traits of spike per square meter (0.91**), grain per spike (0.92**) and total dry matter (0.79*) with grain yield. Therefore, it seems that these traits could be used as indirect criteria for selection of high grain yield of cultivars for primed seed.
