2026-06-11 ワシントン州立大学（WSU）
Washington State University scientists used the hand-written records of longtime sweet cherry breeder Thomas Toyama to break down the precise heritage of breeds he cultivated (composite featuring photos by Cameron Peace/WSU and Алексей Божко/Adobe Stock).
＜関連情報＞
- https://news.wsu.edu/news/2026/06/11/wsu-uses-history-to-breed-better-cherries/
- https://www.maxapress.com/article/doi/10.48130/frures-0026-0010
富山の歴史的な育種記録を調査すると、独特の甘いサクランボの遺伝資源が作られていることが明らかになる Examination of Toyama’s historical breeding records reveals distinct sweet cherry germplasm created
Duygu Caymaz,Stijn Vanderzande,Feixiong Luo & Cameron Peace
Fruit Research Published:27 April 2026
DOI:https://doi.org/10.48130/frures-0026-0010
Abstract
The historical Washington State University Sweet Cherry Breeding Program, led by Dr. Thomas Toyama from 1963 to 1985, developed important and distinct sweet cherry germplasm. The program ultimately released 11 cultivars, including ‘Chelan’, ‘Cashmere’, ‘Glacier’, ‘Tieton’, ‘Kiona’, and ‘Cowiche’. These cultivars and 30 remaining selections contribute significantly to commercial production worldwide and current breeding. However, the origins of this valuable ‘Toyama germplasm’ are unclear. This study relied on hand-written breeding records of crosses and verified pedigree information to analyze the output of this historical breeding program and characterize the genetic origins of Toyama’s germplasm. Dr. Toyama used 103 unique parents from diverse origins to create 241 families, and at least 5,182 germinated seeds formed from at least 88,000 pollinated flowers. Most parents were from North America, especially the most-used ‘Stella’ that generated half of all germinated seeds. Half of the Toyama germplasm’s ancestry was traced to pre-1900 European cultivars, with ‘Napoleon’ representing 25%–33% of the genetic background. For extant selected germplasm, ‘Stella’ and two of Toyama’s own selections were the most used parents, accounting for 52% of recorded parentages. Similar ancestry contributions for selected and pre-selected germplasm indicate that the diverse germplasm accessed persists in extant breeding parents and commercial cultivars. Exploitation of self-fertility and Toyama’s signature complementing of ‘Stella’ with early-season French cultivars could explain the high success rates of pollinated flowers converted into germinated seeds and eventually into cultivars. DNA-based diagnostics could further reveal the ancestry and valuable alleles of this germplasm to inform future breeding endeavors.
