Identification of salt tolerant sugarcane cultivars through phenotypic, physiological and biochemical studies under abiotic stress

Sugarcane is one of the typical glycophyte grass plant which can poorly thrive in saline soil profiles of tropics and subtropics globally. Salt stress is a major physiological constrain drastically influencing plant growth and development. Identification of salt-tolerant cultivars can make a substantial contribution to greater productivity of sugarcane in salt stress prone areas. Based upon descriptive phenotypes 38 sugarcane cultivars were included in the present study. Cultivars evaluated in pots at formative and grand growth stages of development under 8 dSm−1 levels of salts (NaCl, Na2SO4, CaCl2·2H2O; 1:2:1 ratio) during two consecutive cropping seasons. Key morphological, physiological and biochemical traits were measured under different levels of salt stress. Recorded data was converted into relative salt tolerance indices (RSTI) for comparative study among genotypes for salt tolerance with multiple agronomic traits. Significant variations were observed between the cultivars at the both growth stages. RSTI for all the studied traits varied considerably such as; for proline contents it was calculated lowest (102.7) in Co 0239 and highest (287.2) in Co 7717 cultivar. Considering the salt tolerance indices derived from morphological, physiological, and biochemical observations indicated that 13 sugarcane cultivars were tolerant, while 13 moderately tolerant and rest 12 cultivars were not capable to grow optimally in salinity and showed susceptibility to salt stress. The tolerance rank of an individual cultivar was based on genotype rank (GR) determined with RSTI and ward’s minimum variance of studied parameters. GR ranged from 1 to 3, wherein GR 1 denotes tolerant, GR 2 moderate and GR 3 for susceptible to salt stress. To conclude, salt tolerant cultivars identified and salt tolerance-associated traits can be exploited in breeding programs to improve sugarcane production in saline areas.