Enhancing Precision in Pollination: Debunking Misconceptions

Jun 14, 2023 | Pollination

By Gal Sapir

Introduction:

The terminology surrounding pollination often distinguishes between natural and artificial methods. However, when it comes to pollination in horticulture, these terms can be misleading. In this article, we aim to clarify the misconceptions and shed light on the importance of precise pollination techniques. We will explore the impact of mechanical pollination, exemplified by a study conducted on pistachio trees, and discuss the significance of optimizing pollen viability while minimizing non-pollen particles.

The Misnomer of Artificial Pollination:

The term “artificial pollination” was initially coined to differentiate it from pollination performed by biotic or abiotic agents, such as insects or wind, respectively. However, when considering pollination in orchards, there is little that can be deemed natural about the process involving commercial honey bees. Honey bee hives placed in orchards are essentially artificial structures, created to domesticate bees for honey production and pollination purposes. These hives allow for control over bee offspring and the extraction of honey. Furthermore, commercial bee colonies are centered around a queen that is artificially inseminated and placed within the constructed hive, which initiates the natural instincts of treating the offspring, foraging for food, and inadvertently pollinating flowering plants. An orchard’s planting layout is also far from natural. The vegetative production of genetically identical trees planted in rows deviates significantly from the diverse dispersion of species found in nature. Bees and other insects in their natural habitat pass between various plants, feeding on a multitude of flowers, unlike the concentrated environment of an orchard. Consequently, the term “Natural pollination” misrepresents the reality of the process.

Mechanical Pollination:

To rectify the imprecision in terminology, let’s refer to the process of mechanical pollination. Mechanical pollination involves the collection of pollen from flowers and its reintroduction to receptive flowers to facilitate the fertilization process for fruit and nut production. Pollen can be collected by either using a vacuuming method to extract pollen directly from flowers or by harvesting flowers and employing various techniques to extract the pollen. The dispersal of pollen is primarily accomplished by either mixing it with liquids and utilizing general-purpose sprayers or by using designated machines to blow dry pollen mixed with filling materials.

The Impact of Non-Pollen Particles:

An enlightening study conducted by Zhang on pistachio trees in California highlights the potential drawbacks of adding materials during mechanical pollination. Initial observations indicated that dust carried by the wind during flowering led to decreased yields. To investigate further, an extensive experiment was designed to examine this phenomenon. Notably, the region already faced challenges related to wind-borne dust, impacting air quality and residents’ health, as highlighted in a comprehensive PPIC report(2). Zhang conducted tests using various pollen-to-dust ratios, ranging from pure pollen to pure dust and different mixtures in between (e.g., 1:1, 1:4, 1:16).

The results revealed a significant positive correlation between pollen viability and fruit set percentages, as well as a negative correlation to the occurrence of blanks (empty fruits) and split hulls(indicative of compromised fruit quality). Besides the decrease in fruit set percentages, which aligns with a decline in pollen quality, the researchers discovered that dust negatively affected the physical integrity of the pistachio’s style. This further impaired the potential for fruit set and subsequently reduced overall yield. Additionally, when incorporating inert materials with pollen, one must consider the initial viability of the pollen. Pistachio pollen is extremely sensitive to environmental conditions such as temperature, humidity, and light. Therefore, accurate assessment of pollen quality is crucial during mechanical pollination. The researchers employed the Amphasys Z32, the most reliable method available to measure pollen viability efficiently.

This method operates as a flow cytometer, using an electric current to assess a large number of pollen grains within a short time frame. Results of the pollen viability assessment indicated that in applying pure pollen treatment, where no dust was present, only 24% of the pollen grains were viable. This implies that for every viable pollen grain, there were three non-functional ones that acted like dust. These findings expose a potential issue with earlier studies on pollen application in pistachios, where inert materials were often mixed with the pollen. To enhance pistachio mechanical pollination, the results of this study suggest increasing the use of viable pollen while minimizing the dispersion of non-viable and non-pollen particles.

Conclusion:

By dispelling the misconception surrounding artificial pollination and emphasizing the precision of mechanical pollination, we can better understand and communicate the importance of optimizing pollination techniques in horticulture. The study on pistachio trees exemplifies the potential drawbacks of introducing extraneous materials mixed with pollen and highlights the significance of pollen viability in maximizing fruit set and overall yield. Moving forward, it is essential to prioritize accurate pollen assessment and minimize non-pollen particles during mechanical pollination dispersal. By doing so, horticulturalists can achieve improved crop yields while ensuring the sustainable continuation of plant generations.

EDETE’s Precision Mechanical Pollination:

EDETE’s proprietary mechanical precision solution uses pure pollen and avoids the addition of extraneous materials based on a unique dosing system that allows the controlled transfer of small quantities of natural pollen at the right stage of flower receptivity.

(1) Zhang, Lu, et al. “Dust interferes with pollen–stigma interaction and fruit set in pistachio pistacia vera cv. Kerman.” HortScience 54.11 (2019): 1967-1971.

(2) https://www.ppic.org/publication/land-transitions-and-dust-in-the-san-joaquin-valley


Edete Precision Technologies for Agriculture is helping pistachio growers secure and increase yields with a high-efficiency precision pollination solution. Please call us to learn if precision pollination will help your pistachio yields: 1-855-POLLEN-1

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