Taxonomy & Origins
American plums (Prunus americana) are native to which continent and what type of habitats do they dominate?
North America; prairies, woodland edges, river valleys
American plums often act as what type of ecological pioneer species?
Colonizers of disturbed sites, stabilizing soil and aiding succession
The genome of American plum is diploid, with how many chromosomes?
2n = 2x = 16 (or n=8)
What fungus causes black knot in American plums?
Apiosporina morbosa
American plums are traditionally used in what type of foods?
Jellies, jams, pemmican, wines
Despite their name, Japanese plums (Prunus salicina) originated where?
China; domesticated there, later introduced to Japan
Japanese plums require how many chilling hours (range) depending on cultivar?
400–1,000 chill hours
Japanese plums are highly heterozygous. Why does this complicate breeding?
Complex ancestry, self-incompatibility, and polygenic traits
Which quarantine pathogen poses major trade restrictions for Japanese plums
Bacterial spot (Xanthomonas arboricola pv. pruni)
Japanese plums dominate which type of global market?
Fresh fruit markets
Which plant breeder brought Japanese plum seeds to California in the 1870s, shaping modern markets?
Luther Burbank
Which hormone regulates ripening and pigment development in American plums?
Ethylene
Name one UMN-released American × Japanese plum hybrid.
‘Alderman’ or ‘Toka'
The plum curculio causes what characteristic fruit damage?
Crescent-shaped oviposition scars and internal larval feeding
What phytochemicals are particularly high in American plums compared to domesticated plums?
Anthocyanins and diverse flavonoids
Genetic evidence shows P. americana diverged from Eurasian plums millions of years ago. What does this indicate about its evolutionary trajectory?
Independent evolution in North America, with adaptations to local climates
Rising temperatures have what dual impact on Japanese plum bloom phenology?
Earlier bloom, increased frost exposure risk
Which molecular tools are used in Japanese plum breeding for disease resistance and fruit quality?
MAS (Marker-Assisted Selection), QTL mapping, GWAS
What viral disease (virus) is known as “Sharka” and devastates Japanese plums?
Plum Pox Virus (PPV)
Which major countries are top exporters of Japanese plums? (there's 3 to list)
Chile, Spain, US
Compare the domestication processes of American and Japanese plums in terms of cultural stewards and breeding emphasis.
American plums—stewarded by Indigenous peoples for food/medicine; Japanese plums—formally bred in Asia and California for fruit quality
Compare how American and Japanese plums differ in cold resilience and chill hour adaptation.
American—high chill, extreme cold/frost tolerance; Japanese—lower chill, less tolerant of harsh winters
Discuss how interspecific hybridization between P. salicina and P. americana could combine strengths of both species.
Merge Japanese fruit quality & storability with American cold-hardiness & resilience; limited by incompatibility/sterility
Name one major disease that predominantly affects American plums and one that predominantly affects Japanese plums.
American: black knot, leaf spot, rust, bacterial canker, or bacterial blight
Japanese: Bacterial spot, brown rot, leaf curl, scab, plum pox virus(sharka)
Compare niche market opportunities for American vs. Japanese plums
American—farmers’ markets, Indigenous/heritage foods
Japanese—premium export, health-conscious consumers