Drift

(plant breeding) A genetic phenomenon that, in the course of time, a seed propagated cultivar deviates from the original type, due to coincidental fluctuations in gene-frequencies of a population. Risk of drift is higher in smaller populations and can lead to genetic impoverishment (fixation).
Note: In plant breeding the term “genetic drift” is commonly used; “cultivar drift” is a similar term practised in the trade of seeds.
Synonyms: genetic drift, cultivar drift