Assessment of mango rootstocks for salinity tolerance under coastal conditions

Abstract:

Can salt-tolerant rootstocks rescue mango cultivation along eroding coastlines where soil salinity keeps climbing? This research set out to answer that question by screening six polyembryonic mango rootstocks under graded salinity stress at the coastal research block of Anatolian Agricultural University, Ankara, Turkey, from June 2022 to May 2024. One-year-old grafted plants of each rootstock were subjected to NaCl-amended irrigation at 0, 2, 4, 6, 8 and 10 dS m⁻¹ in a factorial completely randomised design with four replications. Shoot elongation, leaf area expansion, chlorophyll stability index, proline build-up, Na⁺ and K⁺ tissue concentrations and root architectural traits were recorded at 30-day intervals. Chandrakaran maintained the highest relative shoot growth (41.3% of control) even at 10 dS m⁻¹, whereas Kurukkan dropped to 24.7%. Leaf Na⁺ was lowest in Chandrakaran (1.39 mg g⁻¹ DW) and highest in Kurukkan (2.68 mg g⁻¹ DW) at the terminal harvest. The K⁺/Na⁺ ratio in Chandrakaran roots remained above 1.8 across all salinity steps, pointing to effective ion exclusion. Proline accumulation rose sharply in tolerant genotypes, reaching 9.74 µmol g⁻¹ FW in Chandrakaran at 8 dS m⁻¹. Bappakai and Mylepelian showed intermediate tolerance, keeping shoot growth above 33% at 10 dS m⁻¹. These results indicate that Chandrakaran and, to a lesser extent, Bappakai are well-suited rootstock options for mango growers in salt-affected coastal belts, offering both ion regulation and sustained vegetative vigour under moderate salinity.