The effects of foliar application of Glycine Betaine on yield and physiological variables of rapeseed (Brassica Nupus L.) under different irrigation regimes

The aim of current study was to study the effect of glycine betaine spraying under different levels of available water on agronomical and physiological attributes of rapeseed (Brassica unpus L.) plants. In this respect an experiment was conducted in randomized complete block design in three replications as split plot in research field of Varamin Islamic Azad University. The factors included irrigation at three levels (I1- normal irrigation, 60 mm tub evaporation, I2- mild stress, 90 mm tub evaporation and I3 – sever stress, 120 mm tub evaporation) and glycine betaine (GB) at four levels (B1 – pure water (without GB), B2 – 1.5 /1000, B3 – 2/1000, and B4 – 2.5 /1000). The interaction between two factor on grain yield, content of chlorophyll a and b, glycine betaine, malon dealdehyde (MDA) was significant. In general, higher concentration of GB as foliar spray especially under lower soil moisture level led to higher grain yield and higher content of measured variables (except MDA). The interaction effect on prolin content and relative water content (RWC) wasn’t significant but simple effects of irrigation and foliar GB were significant. The highest values of RWC (80.87 %) and prolin (15.7 μmol.g.FW) respectively were observed by using 2.5/1000 and 1.5/1000 concentrations of GB. The lowest values proline was showed by using 2.5 / 1000 concentration of GB.