تأثیر سه تنظیم‌کننده رشد بر عملکرد دانه ارقام گندم در رژیم های متفاوت رطوبتی

Plant growth regulators (PGRs) are used to prevent reduction in wheat grain yield under limited moisture conditions. The effect of 3 PGRs including cycocel, salicylic acid and brassinoestroeid on yield and yield components of  four wheat cultivars (Chamran, Shiroudi, Pishtaz and Sirvan) under well watered and water stress (withheld irrigation after flowering) was examined. The experiment was carried out as a factorial split plot in a completely randomized block design with three replicates at research farm of Sarvestan, Fars province in 2014-15 growing season. The results showed that drought stress reduced ear weight, grains per ear, grain weight per ear, thousand grain weight, harvest index, biological yield and grain yield, significantly. Albeit, the extent of the decrease varied, i.e. the smallest and greatest decreases were found in thousand grain weight (7%) and number of grains per ear (13%), respectively. Furthermore, application of PGRs especially cycocel, could increase ear weight, grains per spike, harvest index, thousand grain weight and consequently, grain yield. Among cultivars, Sirvan had the highest and Shiroudi had the lowest yield under both moisture regimes. According to our results although drought stress suppresses wheat yield and yield components, PGRs could be harnessed to compensate some parts of drought stress. Therefore, use of PGRs could be recommended to alleviate the drought stress effect on bread wheat.