Integrated Screening of Salinity Responses in Mango Seedling Progenies from Open-Pollinated Maternal Sources

Mango (Mangifera indica L.) establishment is strongly constrained by soil salinity, yet comparative evaluations of diverse maternal sources for rootstock-related salinity responses remain limited. In mango, embryo type (polyembryonic vs. monoembryonic) is frequently employed as a proxy for vigour and stress tolerance, yet it is uncertain whether differences in performance are attributable to embryo category per se or to genotypic variation within and between these groups. We evaluated seedlings from 21 open-pollinated mango maternal sources (14 monoembryonic and seven polyembryonic types) under saline irrigation at water electrical conductivities of 0.65, 3.0 and 6.0 dS m−1 over an 18-week period. Growth, biomass, leaf gas exchange, optical pigment indices and Na+ and K+ concentrations in leaves, stems and roots were measured. Saline conditions reduced growth, total dry mass, chlorophyll index, net photosynthetic rate and tissue K+/Na+ ratios, but the magnitude of the response differed markedly among maternal sources. Overall, source-level variation provided more informative screening information than the contrast between embryo categories. Candidates were evaluated using performance at 6.0 dS m−1 and performance retention relative to the control. ’Indonesia’ and ‘Pahutan’ maintained comparatively high values for both traits, retaining approximately 80% and 79% of the control total dry mass and 89% and 86% of the control net photosynthetic rate, respectively. ‘Ceylon’ and ‘Baramasi Vengurla’ maintained high absolute biomass under the highest salinity treatment, whereas M. zeylanica, ‘Kerala-5’, ‘Chandrakiran’ and ‘Peach’ expressed favourable responses for selected physiological traits but differed substantially in plant size or biomass retention. Growth, photosynthetic performance and regulation of ion responses were assessed jointly, providing integrated support to the observed contrasts. The integrated screening framework identified maternal sources whose progenies combined favourable growth, photosynthetic and ion-regulation responses, warranting further evaluation using genetically characterised, clonally propagated and grafted material.