Cherries and plant tissue culture

The origin of the sweet cherry

One of the world’s most recognizable fruits is known as Prunus avium, or the sweet cherry. A staple food source that has been cultivated by humans for thousands of years, it is now commonly seen on top of ice cream sundaes or as a garnish in cocktails. Native to Europe and Western Asia, the sweet cherry seed is known to be distributed by several species of birds, which eat this stone fruit and spread its seeds through their droppings.

There are numerous distinct varieties known in addition to the sweet cherry. The sour cherry, Prunus cerasus, is another edible type, as are decorative species such as the Japanese Yoshino cherry. Many people adore this lovely floral type, which, while not producing excellent fruit like other cherry cultivars, is primarily focused on producing vibrantly colored and fragrant flower blossoms in the spring months.

Cherry tree cultivation and cold tolerance

The cherry tree is a deciduous plant that grows in mild climates. These trees require a cold chilling period (known as vernalization) to break winter dormancy and begin flower and fruit production. While they are considered cold hardy, cherry trees can still experience a cold shock if exposed to freezing temperatures when tender blossoms first begin to form in the spring. These late spring freezes can subsequently decrease fruit yields by hindering fruit development. Due to this, it is important to protect growing plants in the early spring if frost or freeze is still expected while plants are coming out of winter dormancy. This can be done by insulating the trees, surrounding the bases of young trees with compost and straw, using a freeze cloth that helps protect young tissues from cold temperatures, and even heaters that can be used in orchards to help protect young, growing plants from freezing temperatures.

Cherries and threats: pests, diseases and environmental issues

Cherries are not only delicious to humans, but to pests and microorganisms. Cherry plants face several issues, including infection by fungal diseases and viruses, consumption by pests as well as occasional environmental issues. In an orchard, some diseases and pests spread from one plant to the rest of the plants, so early detection is important to help prevent the spread and minimize losses. Some common problems cherry trees may experience are:

• Cherry splitting (due to improper watering or droughts);
• Cherry scorch spot (fungal infection);
• Silver leaf (fungal infection);
• Spotted wing drosophila (pest);
• Cherry leaf miners (pest);
• Consumption by birds (pest); and
• Cherry fruit drop (environmental).

New applications: cherry tissue culture

In recent years, cherry plants have been the focus of many new applications in plant research. As technology improves, we are able to further study cherries and how their efficiency and resilience can be improved upon. Plant tissue culture is a method that allows for a sterile and highly controlled growth environment in the laboratory. This type of propagation can prevent fluctuations in watering and photoperiods that cause problems for crops like cherries. Tissue culture can also help prevent the introduction and spread of pests and diseases that can destroy your plants.

Developments in cherry tissue culture and tips for success

Tissue culture-based research in cherries has also helped with the development of pest and disease-resistant varieties, the introduction of genetically unique plants or more uniform populations, drought-tolerant plants, and long-term embryonic storage, just to name a few. Tissue culture also allows for uniform rootstock, and scion tissues to be propagated true-to-type, a method that is not always available to growers using traditional propagation techniques. This is because cherry have diploid chromosomes, and their seed is normally a blend of the DNA of the two parent trees, resulting in 'children' who may not have the ideal fruit characteristics of the parent trees.   

What to consider to have a successful cherry crop in vitro?

Cherries are a popular subject in plant research and production for their wide availability and easy introduction into the laboratory environment. Some questions you may want to ask when getting started with cherry tissue culture include:

• From where am I going to source my cherry tissues?
• Am I interested in obtaining scions or rootstocks, and why?
• Can I guarantee that my tissues will come without viruses and pests?
• What kind of varieties or cultivars am I interested in?
• Do I know the proper conditions to grow cherry plants in vitro?

It is important to note that tissue culture can be a long process, where initial protocols sometimes fail, and different methods need to be tried until a successful process is achieved. Different varieties of plants may react differently to conditions that are known to be successful for others. Due to this, it may be advantageous to try different protocols for new plants to determine which protocol is the best for your needs.

Your checklist for a successful cherry population in tissue culture:

• Proper growth medium and pH;
• Proper photoperiod;
• Proper temperature;
• Regular propagation schedule;
• Sterile lab technique; and
• Annual cold chilling (vernalization).

The checklist above is the cherry on top for the success of your plantlets in the laboratory tissue culture environment. You should familiarize yourself with the requirements of these plants in order to know how to keep them at their best and encourage optimal growth.

For more sweet articles like this, keep checking this space.

By Greyson Phillips | 1st November 2022

Greyson is located in the stunning Pacific Northwest and has recently graduated from Washington State University. He has thoroughly enjoyed his time working in plant research with fruit varieties like apples, cherries, and grapes. He hopes to one day have his own orchard so he might make contributions to plant science and work on the development of the ideal apple pie.

References

• Janick, J. (2010). Horticultural Reviews, Origin and Dissemination of Cherry, Volume 19, pgs 264-313. In Google Books. John Wiley & Sons. https://books.google.com/books?hl=en&lr=&id=jdVY1nF_BjkC&oi=fnd&pg=PA263&dq=cherry+origin&ots=_RWXh4FZFo&sig=VcSXwBm5vXWHHIKk2g17Fj25Wh8#v=onepage&q=cherry%20origin&f=false
• ‌Huxley, A., Griffiths, M., Levy, M., & Horticultural, R. (1992). The New Royal Horticultural Society dictionary of gardening. Volume 1, A-C. Macmillan.
• Ortega-Vidal, J., Cobo, A., Ortega-Morente, E., Gálvez, A., Alejo-Armijo, A., Salido, S., & Altarejos, J. (2021). Antimicrobial and antioxidant activities of flavonoids isolated from wood of sweet cherry tree (Prunus avium L.). Journal of Wood Chemistry and Technology, 1–14. https://doi.org/10.1080/02773813.2021.1910712
• Cherry (including sour) | Diseases and Pests, Description, Uses, Propagation. (n.d.). Plantvillage.psu.edu. Retrieved October 14, 2022, from https://plantvillage.psu.edu/topics/cherry-including-sour/infos
• ‌ Pauly, P. J. (1996). The Beauty and Menace of the Japanese Cherry Trees: Conflicting Visions of American Ecological Independence. Isis, 87(1), 51–73. https://doi.org/10.1086/357402
• https://www.researchgate.net/profile/Hristina-Kutinkova-2/publication/264840909_INTEGRATED_PEST_MANAGEMENT_IN_SWEET_CHERRY_Prunus_avium_L_ORCHARDS_IN_BULGARIA/links/54a6741b0cf256bf8bb5168e/INTEGRATED-PEST-MANAGEMENT-IN-SWEET-CHERRY-Prunus-avium-L-ORCHARDS-IN-BULGARIA.pdf