Evaluation of salt-tolerant germplasm of mulberry (Morus L.) through in vitro and field experiments under different salinity stresses

Twenty-five promising salt-tolerant mulberry germplasms from different Morus species were evaluated for growth under varying salinity levels (10.20–25.60 dS m−1) typical of the coastal regions in South 24 Parganas, West Bengal. Evaluations were conducted using in vitro axillary bud culture and field experiments under natural conditions to identify superior salt-tolerant germplasms. Soil sample analysis revealed significant variation in salinity levels (34.37–17.09 dS m−1) across different areas, with the highest in Kultali and the lowest in Canning I and II. Among the 25 germplasms, 6 were identified as highly salt-tolerant, 6 as moderately high salt-tolerant, 11 as salt-tolerant, and 2 as salt-sensitive. Survivability rate and root length were found to have the highest correlation with salt tolerance during early development. The six highly salt-tolerant germplasms, including English Black, Kolitha-3, C776, Rotundiloba, BC259, and S1 were further tested in field trials. English Black showed the highest survivability rate of 69.2 % in soil salinity of 18–20 dS m−1. Results from in vitro and field trials were consistent, with a strong positive correlation between survivability rate and root length. This study establishes an effective method for evaluating salt tolerance in mulberry, providing a foundation for more efficient assessments.