Influence of Nutrient Sources and Application Timings on Grafting Success, Growth, and Physiology of Mango ( Mangifera indica L.) Nursery Plants Under the Agroecological Conditions of Multan, Pakistan

The production of vigorous and uniform mango nursery plants largely depends on successful graft union formation and optimized nutrient management. Therefore, the present study evaluated the influence of different nutrient sources and application timings on graft success, growth, and physiological performance of grafted mango nursery plants. Cleft grafting was performed on 28 February during the 2024–25 nursery season. The experiment was designed using a completely randomized design (CRD) in a factorial arrangement with three replications. Plants received four nutrition sources, i.e., S 0 : Control, S 1 : N:P:K (20:20:20) (5 g), S 2 : diammonium phosphate (DAP) (2.17 g) + sulphate of potash (SOP) (1.7 g) + urea (1.78 g), and S 3 : nitrophos (NP) (5 g) + SOP (1.7 g), applied at four different timings: (T 1 ) at grafting, (T 2 ) 1 week after grafting, (T 3 ) 2 weeks after grafting, and (T 4 ) 3 weeks after grafting. Results showed that higher plant height (78.96 cm), graft success (78.88%), number of flushes (6.33), stem girth (1.11 cm), photosynthetic rate (19.52 µ mol CO 2 m −2 s −1 ), stomatal conductance, and transpiration rate (90.25 and 50 mmol H 2 O m −2 S −1 respectively), as well as nitrogen (1.80%), phosphorus (0.29%), and potassium (0.64%) contents were recorded in S 2 , while lower values were observed in S 0 . Similarly, for application times, T 4 exhibited higher plant growth, physiological parameters, and chlorophyll contents. However, enzymatic activities such as superoxide dismutase, peroxidase, and catalase (55.81, 30.55, 33.36 U mg −1 protein, respectively) were higher in S 0 at T 1 . Therefore, it was concluded that S 2 : DAP (2.17 g) + SOP (1.7 g) applied at T 4 (3 weeks) after grafting is more effective for graft success, physiology, vigor, and overall health of mango nursery plants. This treatment is recommended for mango nurseries in the study area and has practical implications for other regions with similar agroecological conditions.