Plant architectural traits and their role in defense mechanism against malformation in mango (Mangifera Indica L.)

Different physiological factors related to intensity of floral malformation in twelve mango cultivars differing in their degree of resistance to malformation were investigated. The results revealed that thickness of leaf blade had no significant correlation with intensity of floral malformation, but mango resistant cultivars Bhadauran and Elaichi showed thicker leaf blade when compared with highly susceptible cultivar like Eldon. Leaf wax content showed highly significant negative correlation with intensity of mango floral malformation (r = −0.88). Results revealed that highly susceptible cultivars have less wax thickness (315–375 μg/cm2) when compared to resistant cultivars (484–522 μg/cm2). The number of stomata per unit area (mm2) of leaf surface did not show significant correlation (r = −0.28) with intensity of malformation, but the total number of stomata per leaf showed significant positive correlation (r = 0.53) with percent malformation intensity in mango cultivars. Maximum number of stomata per leaf surface area was found in highly susceptible cultivar Amrapali, followed by susceptible cultivar Chausa. Whereas minimum number of stomata per mango leaf surface was found in resistant variety Bhadauran. Stomata size (length and breadth) and width of stomatal aperture did not show significant correlation with intensity of floral malformation. Intensity of malformation had significant positive correlations to leaf length, width, weight and leaf area r = 0.59, 0.53, 0.57 and 0.55 respectively.

► Mango malformation had positive correlation with total number of stomata per leaf, leaf length, leaf breadth, leaf area and leaf weight, and negative correlation with leaf wax coating.
► No correlation was observed with leaf thickness, number of stomata per unit leaf area, stomata length, stomata breath and width of aperture.
► Physical parameters like leaf wax content, small leaf size with fewer numbers of stomata per unit leaf area can be used for identification of mango varieties resistant to malformation.