Multivariate analysis of the salinity-induced alterations in morphology, physiology, nodulation, and yield in two contrasting mungbean varieties

Abstract

Changes were estimated in the morphology, physiology, photosynthesis, nodulation, and yield in two mungbean varieties ‘PKV AKM 12-28’ and ‘VBN (Gg)3’ under salt stress (0, 75, 100, and 125 mM NaCl) for 15, 30, and 45 days. Multivariate modelling was used to analyse results to explore complex data and to visualize time and concentration-dependent modulations. Principal component analysis showed modulations in morpho-physiological attributes such as shoot length, root length, the number of secondary branches, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight and leaf area; photosynthetic attributes such as chlorophyll ‘a’, chlorophyll ‘b’, total chlorophyll, total carotene and total anthocyanine content; nodulation attributes such as nodules per plant, size of the nodule, and fresh weight per nodule, and yield attributes such as number of pods per plant, fresh weight per pod, and seed characteristics such as the number of seeds per pod and fresh weight per 1000 seeds are key traits affected by salt stress and can be used as indicators. Discriminant analysis identified modulations in morpho-physiological attributes such as root length, leaf area, root fresh weight, shoot fresh weight, shoot dry weight, shoot length and photosynthetic attributes such as chlorophyll-a content, and mean nodule weight as discriminating variables at different salt concentrations. Besides, it identified modulations in morpho-physiological attributes such as root length, root fresh weight, photosynthetic attributes such as total anthocyanin content and total chlorophyll content, nodulation attribute such nodule size and nodule weight, and yield attributes such as pod number and number of seeds per pod are discriminating variables at various durations of salt stress. Principal component analysis and discriminant analysis identified ‘PKV-AKM 12-28’ as salt-tolerant and ‘VBN (Gg)3’ as salt-susceptible varieties. Multiple correlation analysis identified significant correlations among morphological, physiological, photosynthetic, nodulation and yield parameters.