Improvement in growth, productivity and quality of 'Kinnow' mandarin fruit after exogenous application of Moringa olifera leaf extract

Low productivity and poor fruit quality of 'Kinnow' mandarin (Citrus nobilis Lour x C. deliciosa Tenora) are major issues faced by growers. Moringa (Moringa olifera L.) leaf extract (MLE) being rich inminerals, growth hormone (cytokinins), phenolic compounds and antioxidants is considered as promising natural growth promoter for plants. Hence, the present research was planned to evaluate the efficacy of MLE on leaf nutrient concentration, productivity and fruit quality of 'Kinnow' mandarin. In first experiment effect of different concentration of MLE (2%, 3%, 4% or 5%) sprayed to 'Kinnow' trees after harvest were studied on leaf mineral nutrients, chlorophyll and ascorbic acid contents. Result showed that 3% MLE foliar application increased the levels of mineral nutrients, chlorophyll a and ascorbic acid contents in 'Kinnow' mandarin leaves as compared to other treatments. In second experiment, 3% MLE was sprayed at different growth stages viz., at before flowering (February), at full bloom stage, before flowering + fruit set stages, pre mature stage (3rd week of September) or flowering + full bloom stage + pre-mature stages. Results indicated that highest increase in leaf K, Ca and Zn contents, yield, number of marketable fruits, soluble solid contents, reducing sugars and total phenolic contents were found with 3% MLE application at pre mature stage. Whereas, maximum leaf Mn, chlorophyll a and b concentrations, fruit weight, fruit size, juice weight, titratable acidity (TA), total and reducing sugars were observed in trees treated with 3% MLE at before flowering + fruit set stages. Total antioxidants were found to be higher in fruits treated with 3% MLE at before flowering. Thus, itmay be concluded that exogenous application of 3% MLE at before flowering + fruit set stage improves fruit physical quality; whereas, 3% MLE at pre mature stage increases the yield and bio-chemical quality of 'Kinnow' mandarin fruit. (C) 2019 SAAB. Published by Elsevier B.V. All rights reserved.