Fruits and Nuts
Almond ‘Yorizane’ – Self-fertile
‘Yorizane,’ (Prunus dulcis (Mill.) D.A. Webb) the Self-Fertile Almond
Rachel Spaeth
USDA-ARS National Clonal Germplasm Repository-Davis, One Shields Ave, Davis, California 95616.
Corresponding author: rachel.spaeth@usda.gov
OUTLINE
- Summary
- Problems addressed
- Solutions developed
- Impact
- Germplasm
- Additional resources
- Chapter information
1. SUMMARY
In 1996, Craig Ledbetter of the USDA-ARS Crop Diseases, Pests, and Genetics Research Unit in Parlier, California started breeding almonds with a goal of introducing self-fertility to an historically outcrossing crop. This started with a self-fruiting cultivar called ‘Tuono’ (DPRU 2301) and led to the eventual development of ‘Yorizane,’ released in 2021. Adoption of this new cultivar will lead to a drastic reduction in the need for pollination services, with a potentially large cost savings for the almond industry.
The goal of this project was to introduce a self-fertile almond with yield, vigor, and quality that would match the most popular self-sterile commercial cultivar, ‘Nonpareil,’ ultimately reducing industry reliance on migratory pollination services.
Download a printable fact sheet by clicking the image below.
2. PROBLEMS ADDRESSED
Almonds (Prunus dulcis (Mill.) D.A. Webb), ranked as one of the top ten crop commodities (by farmgate value) that the U.S. specialty crop exports, grossed more than $4.666 billion in 2022. The vast majority of the almonds in cultivation today are self-sterile, requiring a second almond cultivar and an abundance of imported bees to ensure successful pollination and a sufficient yield of fruit. Pollination services account for at least 15% of almond growers’ operational costs annually. Additionally, incorporating the pollinizing trees into orchards requires field space and careful labeling to ensure the pollinizer nuts are not mixed in with the fruit from the desired cultivar, which would decrease the marketability of the product.
3. SOLUTIONS DEVELOPED
Plant geneticist Dr. Craig Ledbetter saw the potential for self-fertility in an accession of Spanish almond maintained at the USDA-ARS National Clonal Germplasm Repository (NCGR) in Davis, California; however, ‘Tuono’ (DPRU 2301) lacked some of the favorable traits that would enable it to compete with the self-sterile market standard, ‘Nonpareil.’ After 25 years of careful selection and conventional breeding, Ledbetter’s self-fertile creation, ‘Yorizane’, is ready for commercial production. It shares an overlapping bloom period with ‘Nonpareil’. ‘Yorizane’ and ‘Nonpareil’ also share a low frequency of a defect that caused double kernels, as well as a similar crack out percentage. Yield of the two cultivars is comparable. ‘Yorizane’ bears fruits with medium shell thickness, light kernel color, and light wrinkled kernel texture, making then ideal for current market preference. It ranked within the top fourth quartile of sensory panels for both texture and appearance.
Collaborators involved in developing solution:
- Craig Ledbetter, USDA-Agricultural Research Service, Parlier, California
4. IMPACT
The introduction of a self-fruitful almond cultivar would reduce the industry’s reliance on migratory pollination services at a grower savings of roughly 15% of their annual operating costs.
5. GERMPLASM
‘Tuono’ (DPRU 2301) is the genebank accession that conferred the self-fertility trait to ‘Yorizane’.
6. ADDITIONAL RESOURCES
Important information about the release of ‘Yorizane’ can be found in this scholarly article, “‘Yorizane’: A New Self-compatible Almond Cultivar Suitable for California Production“, as well as this USDA-Agricultural Research Service press article, “Researchers Develop Self-Pollinating Almond With a Gold Mine of Tasty Traits“.
Data for the cultivar’s performance were also published by the Almond Board of California in the “2023 Almond Almanac” (click to download); note that ‘Yorizane’ is referred to as Y116-161-99.
“How will changes in almond pollination effect tree fruit“, an article from Washington State University, discusses the relationship between the almond and beekeeping industries.
The following video from Duarte Nursery provides helpful descriptions of nut quality. It is available from this YouTube playlist. Additional resources on this cultivar can be found on Duarte’s website. The use of trade, firm, or corporation names in this page is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the United States Department of Agriculture or the Agricultural Research Service of any product or service to the exclusion of others that may be suitable.
7. CHAPTER INFORMATION
Citation: Spaeth R. 2025. Almond ‘Yorizane’ – Self-fertile. In: Volk GM, Chen K, Byrne P (Eds.) Plant Genetic Resources: Success Stories. Fort Collins, Colorado: Colorado State University. Date accessed. Available from https://colostate.pressbooks.pub/pgrsuccessstories/chapter/almond-yorizane-self-fertile/
Content originally submitted: November 5, 2024
Date of publication: May 19, 2025
USDA is an equal opportunity provider, employer, and lender. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.
