Screening olour mango half-sib progenies for dwarfing, vigour, and climate resilience

Mango (Mangifera indica L.) productivity is limited by large canopy size and the absence of reliable dwarfing rootstocks. The polyembryonic genotype 'Olour' is widely used as a dwarfing and salt-tolerant rootstock, but its zygotic progenies remain underexplored. We evaluated 14 Olour-derived half-sib progenies (5-year-old seedlings) for 40 morphological, physiological, and biochemical traits to identify candidates with dwarfing or vigorous growth tendencies and stress resilience. Multivariate analyses (PCA and hierarchical clustering) revealed substantial variation; the first two principal components explained 26.9% and 13.3% of the variance, respectively (40.2% cumulative). Correlation analysis highlighted bark-to-wood ratio, specific leaf weight, stomatal density, and phenolic accumulation as key indicators differentiating dwarfing from vigour. Progenies O9, O14, and O17 exhibited compact growth and biochemical signatures consistent with dwarfing potential, whereas O1, O3, and O4 showed vigorous growth with high carbohydrate reserves. Progenies O11 and O15 displayed elevated antioxidant enzyme activities, while O19 combined vigour with increased proline. These genotypes represent promising candidates for further validation through grafting trials, anatomical and hydraulic studies, hormone profiling, and multi-site yield testing. This work establishes a multi-trait physiological and biochemical framework to prioritize Olour-derived rootstock candidates for targeted anatomical and molecular follow-up.