In Spain there is a total of 143,170 ha dedicated to orange cultivation (FAO, 2021), making it the main producer in Europe. One of the problems associated with the management of these farms is fruit drop.
The flower load of citrus fruit trees depends on several factors: the variety, the age of the tree and the environmental conditions. It is estimated that sweet orange varieties produce around 50,000 flowers per tree at flowering time, although 95% to more than 99% of flowers fall and only a small number of these flowers develop into ripe fruit (Hussain and Hafiz, 2011). After fruit set, there are fruit drop losses due to physiological causes or due to fungal infections and/or pests. The physiological causes of fruit drop can be due to: sudden changes in temperature or humidity, poor nutritional management, hormonal imbalance, lack of soil moisture, etc. Fruit drop has a high economic impact on commercial farms. To reduce these losses, products based on growth regulating hormones or auxin-based phytoregulators are used. Phytoregulators control the hormonal balance of the tree in the abscission layer of the fruit, reducing or delaying fruit drop and preventing production losses (Lengua, 2020).
The fruit separates from the tree through the abscission zone, creating the abscission layer, due to the degradation of the cell walls by the action of hydrolases, such as cellulase, on bark cellulose. There are different hormones that are capable of altering this process, such as ethylene, which accelerates it, and auxins, which slow it down. Auxin-based products inhibit flowering as well as producing phytotoxic effects, such as deformation or curling, if applied at sprouting. On the other hand, the limitations on the maximum residue limit established by large distribution chains highlights the search for efficient and safe alternatives to prevent or reduce fruit drop in citrus fruits (Castillo, 2011).
In search of biotechnological solutions that constitute an alternative to synthetic products, studies have been carried out on two varieties of orange trees, clemenvilla "Nova" and "Power", where we applied BIOKELAT Co-Mo. BIOKELAT Co-Mo is a product manufactured thanks to FPB® and MAMPs® technologies, activating crucial enzymes for the optimal functioning of plant metabolism. In addition to supplying essential nutrients to activate photosynthesis and prevent oxidative stress in plants.
The foliar application of BIOKELAT Co-Mo reduces fruit drop by 25.26% with respect to the commercial reference used in citrus fruits of the clemenvilla "Nova" variety.
REFERENCES
Lengua Álvaro, J. (2020). Estudio de distintos productos fitorreguladores para retrasar la abscisión de frutos cítricos en la variedad lane late.
HUSSAIN, A., & HAFIZ, I. A. (2011). Phenological behaviour and effect of different chemicals on pre-harvest fruit drop of sweet orange cv. ‘Salustiana’. Pak. J. Bot, 43(1), 453-457.
Castillo, I. P. (2011). Aplicaciones de fitorreguladores en cítricos. Phytoma España: La revista profesional de sanidad vegetal, (230), 42-46.
