Chitosan and salicylic acid: Its role in growth and biochemical characteristics of floral malformation in mango (Mangiferae indica L.)

Abstract

Mango (Mangifera indica L.) is the fifth largest cultivated fruit crop globally with the yields of approximately 58.4 million tonnes, second only to banana among the tropical fruit species (FAOSTAT, 2019). Mango malformation (MMD) is an ambiguous disease of mango with the tremendous economic importance throughout the mango growing regions. The experiment was laid out in Randomized Block Design (RBD) with three replications. Seven different concentrations of chitosan and salicylic acid viz. (Control, 0.25% CT, 0.50% CT, 0.75% CT, 0.20% SA, 0.40% SA and 0.60% SA) were sprayed at three different stages i.e. prior to panicle emergence, pre blooming and full bloom in the month of February to March on two mango cultivars Amrapali (moderately susceptible) and Dashehari (Moderately resistant). The data revealed that chitosan 0.50% shows maximum length of healthy panicle (12.47 cm), malformed panicle (9.45cm), total chlorophyll content (4.90 mg g-1 fr. wt) and phenolic content (296.92) over control. On the contrary, highest weight of healthy panicle (32.33g) and malformed panicle (71.50g) was recorded in 0.60% SA and 0.20% SA treatment. However, maximum leaf area (77.85 cm2) and MDA content (8.56 n molg-1fr. wt.) was at 0.40% salicylic acid treatment over control. Among both the varieties maximum growth characteristics were recorded maximum in Amrapali than Dashehari. However total chlorophyll and phenolic contents was recorded highest in Dashehari as compared to Amrapali. Therefore, it was concluded that protective application of either chitosan or salicylic acid prior to panicle emergence, pre blooming and full bloom reduced the negative effect of mango malformation by increasing growth characteristics and elevate the defense induced antioxidant activities to confer resistance to floral malformation.