Identification of water deficit stress tolerant genotypes of common bean using adaptive root and shoot traits under different screening systems.

Common bean is an important component of global nutritional security. Climate change driven water deficit stress impairs crop performance by implicating both above and below ground plant parts in crops like common beans that are largely grown in marginal low input farming systems. In order to develop climate resilient bean cultivars, it is imperative to understand response of root and shoot traits to water deficit stress and identify genotypes with adaptive plasticity under stress. In the present study, we assessed the differential response of 45 bean genotypes for root and shoot traits under agar system, PEG-6000 mediated in vitro stress as well as column culture in greenhouse. There was significant genetic variability in per se response and plasticity of root and shoot traits, under control and water deficit stress, Basal root angle ranged from 36.67 to 56.67 while as basal root number had a range of 7.45-14.33. Severe reduction in root and shoot traits was observed under water deficit stress in shoot biomass (60.20%), followed by plant height (42.40%), root biomass (31.50%), while as lowest decrease was observed in rooting depth (13.33%). However, root-shoot ratio increased by 89.05% under water deficit stress. Pearson correlation and PCA revealed that root depth and root biomass significantly impact plant height, shoot biomass and number of leaves further reaffirming our hypothesis that roots traits are important selection attributes for above ground plant performance under stress conditions. Genotypes WB-216 and N-2 were superior for most of the traits with adaptive plasticity response to water deficit stress and can be used for development of climate resilient bean varieties.