Reducing Water Stress in Green Bean using Glycinebetaine Application

Abstract

Water shortage represents a severe threat to the crop production sustainability. The present study aimed at investigating the possible role of exogenous glycinebetaine (GB) application (control, 5, 10, 15 and 20 mM/L) in improving the vegetative growth and yield of green bean (Phaseolus vulgaris L.) under different irrigation regimes 55, 70, 85 and 100% of irrigation requirements (IR). A field experiment was conducted, during the two seasons of 2017 and 2018 in split-plot design with three replications at the experimental farm, Faculty of Agriculture, Ain Shams University, Qalubia governorate, Egypt. The main plots were occupied by irrigation treatments and glycinebetaine concentrations distributed in the subplots. The results of the experiment showed that the highest significant values vegetative growth characteristics (plant height, number of leaves per plant, number of branches per plant, total plant fresh weight) were obtained by the 100% irrigation level in the two seasons as compared to the other studied irrigation treatments. In contrast, the 85% irrigation level had positive effects on some yield characteristics (number of pods per plant, pods length, pods thickness, early yield and total yield) for green bean. Foliar application of glycinebetaine at 20 mM/l ameliorated the negative effects of water stress and produced the highest significant values of tested characteristics in the first and second seasons, Moreover, irrigation treatment of 85% IR and foliar application of 20 mM/L glycinebetaine produced the highest yield and fruit quality (pods number, pods length, pods thickness). In addition, the foliar spray of glycinebetaine improved water use efficiency under water stress conditions.