Salinity-induced changes in growth morphology, gas exchange and leaf abscisic acid level of fifteen polyembryonic mango (Mangifera indica L.) genotypes

Mango is a commercial fruit crop in different parts of the tropical and subtropical world. Commercially important monoembryonic varieties are propagated through grafting onto rootstock seedlings of polyembryonic genotypes that plays an important role in sustained growth and production. Use of salt tolerant genotypes as rootstock to combat the adverse effect of salinity could be helpful for commercial mango production in salt affected areas. Current study was carried out to elucidate the effect of salinity stress induced by NaCl + CaCl2 (1:1 w/w) at 0, 25, 50 and 100 mM concentrations in irrigation water on candidate polyembryonic mango genotypes namely EC-95862, Bappakkai, Vellaikolamban, Nekkare, Turpentine, Muvandan, Kurukkan, Kensington, Olour, Manipur, Deorakhio, Vattam, Mylepelian, Sabre and Kitchener. We studied the morpho-physiological changes of these seedlings under salinity induced stress for determining their relative tolerance by assessing growth parameters such as plant height, number of leaves, leaf area, inter-nodal length, fresh weight of shoot, fresh weight of root, dry weight of shoot, dry weight of root, stem diameter and physiological parameters like photosynthetic rate, transpiration rate, stomatal conductance, number of stomata and stomata length and width, in addition to ABA content in leaves. Our results clarifies that the polyembryonic genotypes Turpentine, Deorakhio Olour and Bappakkai showed less reduction in terms of growth and better maintenance of gas exchange status under higher level of salinity.