How to achieve optimal fruit set?
The Effective Pollination Period (EPP) is the window of time during which a flower can be successfully fertilized. It corresponds to the interval in which the ovule remains viable and the pollen tube reaches the embryo sac before the ovule deteriorates. If the pollen tube does not arrive in time, fertilization does not occur and, as a result, the fruit either fails to form or later drops.
The three processes that determine the EPP are: (i) stigma receptivity, (ii) pollen tube kinetics, and (iii) ovule development (Sanzol, 2001). In general, the pollen tube develops more slowly at low temperatures, which benefits ovule longevity. Conversely, high temperatures accelerate pollen tube growth but also hasten the degeneration of the stigma and ovule.
Ensuring optimal seed fertilization is particularly important in fruit species with naturally low fruit set and retention rates, and where abiotic stress factors can slow pollen tube growth and reduce the brief window of opportunity for fertilization.
In this context, numerous field and laboratory studies indicate that the use of biostimulants can enhance pollen germination and pollen tube elongation, promoting more effective fertilization and, consequently, improved fruit set and yield (Gupta et al., 2024). Kelpak® is a powerful biostimulant that increases pollen viability, boosts germination, and ultimately stimulates pollen tube elongation. The delicate balance and pristine molecular structure of its bioactive compounds, such as phlorotannins, polyamines, and brassinosteroids, make this biostimulant a key ally in achieving efficient fruit set and retention.
Improving fruit set
Dr Paul Hills, Head of Research, Development and Innovation at Kelp Products, explains: “Over the years, we have observed that Kelpak® has made a positive impact on pollen germination and tube elongation across a wide range of species.
A recent olive tree study conducted by a leading research centre showed a positive impact on pollen viability and tube elongation when pollen was collected from inflorescences treated with Kelpak® during the flowering stage, along with other notable physiological effects.”
Achieve optimal fruit set in olives
Full bloom (BBCH 65) 30-50%
Apply during full flowering and fruit set at a dose of 5 L/ha
At fruit Set (BBCH68)
Foliar spray at fruit set (BBCH 68) at a rate of 5 L/ha
Spray up to 3-5mm fruit size
Foliar spray after fruit set (BBCH 68) up to 3-5mm fruit size at 5 L/ha
How Kelpak benefits fruit set and yield in olive production?
- Pollen germination: Kelpak increases pollen viability boosting germination.
- Pollen tube elongation: Fertilization is more consistent and effective with better tube elongation.
- Fruit retention: Trees develop tolerance to abiotic stress like high temperatures, reducing fruit drop.
- Drupe size and weight: More fruit with above average drupe size and weight means better marketable yields.
References
Sanzol, J. (2001). Influence of temperature on pollen germination and pollen tube growth of pear cultivars (Pyrus communis L.). Scientia Horticulturae, 90(1–2), 121–130.
Gupta, S., Novák, O., Kulkarni, M. G., Doležalova, I., Van Staden, J., & Doležal, K. (2024). Springer Nature. Unleashing the potential of biostimulants in stimulating pollen germination and tube growth. Journal of Plant Growth Regulation.
