Characterising Flower and Fruit Drop in Two Citrus Species and Their Organic Management with Seaweed Extract Application

Citrus flower and fruit drop is a big global issue, and its organic management is extremely difficult. Citrus plants older than fifteen years exhibited higher rates of flower and fruit drop according to the study’s results. Additionally, the fruit diameters and fruit carbohydrate content of fallen fruits were less than those of retained fruits. It was found that boron was a restricting factor in the plant and soil, causing the citrus flower and fruit drop. According to the study’s inferences, applying seaweed sap treatments on a monthly basis will improve the Sikkim mandarin and rough lemon’s morphological, physiological, and biochemical characteristics while also increasing their market value. The treatment of 10% AN (Ascophyllum nodosum) sap was found to have the significantly highest post-bloom fruit set, 10% KA (Kappaphycus alvarezii) sap +75% recommended dose of organic nutrient (RDON) was found to have the significantly highest total soluble solids, and 10% GE (Gracilaria edulis) sap +75% RDON was found to have the highest pre-harvest fruit set. When seaweed sap is sprayed to both citrus species, abscission-inducing genes CitSAUR06, CitSAUR08, CitSAUR44, CitSAUR61, and CitSAUR64 are down-regulated. It can be concluded that, the use of several seaweed sap treatments topically had a notable impact on the citrus species’ net return, productivity, and economic efficiency.