Harnessing traditional mango cultivars to validate the influence of rootstock and its age on softwood grafting in Kuttiattoor mango: A GI-registered cultivar of North Kerala

Kuttiattoor mango, a geographical indication (GI)-registered traditional cultivar of North Kerala, is renowned for its unique taste and yellow-orange colour. However, being polyembryonic, it is mainly propagated through seeds, resulting in tall trees, a prolonged juvenile phase and difficulty in harvesting. In this context, the present study was undertaken to explore the potential of traditional mango cultivars as rootstocks for softwood grafting in Kuttiattoor mango. Four rootstocks viz. Vellaikolumban, Kurukkan, Kalapady and Kuttiattoor were assessed across three age groups (1, 2 and 3 months old) for softwood grafting. Grafts prepared with 3-month-old Kuttiattoor rootstocks recorded the highest sprouting percentage (73 %), survival percentage (41.92 %) and the fewest days to sprout (12.5). The same combination also produced superior vegetative growth, which was on par with 3-month-old Kalapady rootstocks at 140 days after grafting (DAG). The lower graft growth observed in Kuttiattoor grafts on Vellaikolumban and Kurukkan rootstocks suggests a dwarfing effect, highlighting their potential utility for developing compact, high-density mango orchards. Histological studies revealed better callus growth and vascular differentiation in grafts prepared with 3-month-old Kuttiattoor rootstocks followed by those with 3-month-old Kalapady rootstocks. Grafts with 3-month-old Kuttiattoor and Kalapady rootstocks were found to be the most suitable for nursery propagation of Kuttiattoor mango. The reduced vegetative growth observed on Vellaikolumban and Kurukkan rootstocks indicates their potential for future evaluation as dwarfing rootstocks in high-density mango production systems.