ALLEVIATION THE ADVERSE EFFECTS OF SALINITY STRESS ON SOYBEAN CULTIVARS BY FOLIAR SPRAYING OF ARGININE

The present study was carried out at the experimental farm of Tag El-Ezz Agricultural Research Station (30 o 59 \ N latitude, 31 o 58 \ E longitude ́), Agricultural Research Center, Dakahlia Governorate, Egypt, to study the effect of foliar spraying of arginine on four soybean cultivars under salinity stress. This experiment was laid out in a split plot design with three replicates during the two successive summer seasons of 2020 and 2021. The main plots were occupied by four soybean cultivars (Giza 111, Giza 21, Giza 35 and Crawford), while subplots contained arginine treatments i.e. without spray (control), spray with arginine at 200 and 300 mg l -1 . The obtained results showed that, cultivars showed a wide range of variation in their salinity sensitivity where, Giza 111 gave the highest values of the most vegetative growth parameters i.e., chlorophyll content, relative water content (RWC%), nutrients content in leaves, proline content as well as catalase and peroxidase enzymes activities, thus increased seed yield, seed nutrients, protein, carbohydrates and oil %. Concerning, foliar spraying of arginine ameliorate inhibitory effect of salinity on soybean cultivars in comparison to the control. The highest values of most studied vegetative growth parameters, yield and yield components were achieved by foliar spray of arginine at 300 mg l -1 . The interaction between soybean cultivars and foliar spraying of arginine revealed that, Giza 111 treated with arginine at 300 mg l -1 gave the highest values of growth, yield and yield components.