Morpho-physiological analysis of salinity tolerance in sugarcane genotypes

The productivity of important crops, particularly sugarcane, is greatly impacted by increased crop vulnerability to changing climatic conditions, including various abiotic stress factors like temperature, waterlogging, drought, etc. Salinity tolerance potential of five high yielding sugarcane genotypes was determined based on morpho-physiological, biochemical, and yield traits. The findings showed that morphological features (plant height, leaf area, stem diameter, number of internodes, and internodal length) were suppressed under salinity stress (ECiw 4, 8 and 10 dS/m). The relative water content (RWC) decreased by 4.4-12.5% as salinity level increased. Solute potential (Psi s) ranged from - 1.11 to - 2.27 MPa, whereas the water potential (Psi w) dropped from - 0.86 to - 1.99 MPa (from control to ECiw similar to 10 dS/m). Genotypes Co 13035 and Co 0118 maintained higher plant water status. There was a reduction in pigments and gas exchange traits due to increase in salinity in comparison to their respective control. Proline concentration increased up to seven times under salinity stress, with greatest accumulation in Co 0238 and Co 13035. The ionic (Na+/K+) ratio increased by 4, 6, and 8 times respectively under ECiw 4, 8 and 10 dS/m as compared to the control. The genotypes that were most resistant to salinity stress were Co 13035, Co 0238, and Co 0118, which had low Na+/K+ ratio. The results concluded that genotype Co 13035 had highest survival rate, low Na+/K+, maintained higher water content and osmolyte accumulation, better chlorophyll content, and single cane weight under salinity stress, thereby could be considered as tolerant to salinity.