Physiological and biochemical characterization of sugar beet against salt-stress

Salt stress is a major problem at the global level and it is very important to utilize salt-affected soils using appropriate techniques. Growing halophytes on saline-sodic soil is a win-win strategy for getting economic crop production and conservation of soil resources. However, it is prerequisite to identify the cultivars which can be recommended for salt-affected soils considering physiological and biochemical responses under salt-stress. Therefore, sugar beet cultivars were characterized at seedling stage based on growth, physiological and biochemical parameters under different levels of salt stress. A hydroponic experiment was conducted using eight sugar beet cultivars (AMALDI, GELLERT, VANGELIS, VEDA, WYNNYK, SERENADA, CALIFORNIA and ALBINA VEREDUANA) and two salt stress levels (60 and 120 mM NaCl) in comparison with that of an untreated control. The plants were harvested ten days after giving salt stress. Cluster dendrogram and principal component analysis were the most appropriate methods for screening the suitable cultivar. Most of the sugar beet cultivars responded as resistant against salt stress, however, VEDA cultivar performed best against it. Thus, VEDA cultivar acquired highest position at 60 mM NaCl showing 6.4% plant biomass improvement as compared to control, while 2.1% reduction was recorded at 120 mM NaCl as compared to 60 mM NaCl. Additionally, this cultivar showed highest growth attributes, antioxidant activity with higher K+/Na+ ratio, hydrogen peroxide, phenolic and malondialdehyde content, indicating strong defense mechanism against salt induced oxidative and osmotic stress mainly owing to the best K+ and Na+ balance. It is concluded from this study that VEDA is the best salt-resistant cultivar with great potential to be grown on salt-affected soils and can be proceeded for field trials at various salt-stress levels.