While clonal propagation may seem like it would result in lower genetic variation, the authors observe that clonal propagation and a long juvenile phase means perennial tree-crops have actually gone through fewer sexual cycles since domestication and thus have remained closer, genetically, to their wild progenitors. Indeed, perennial fruit crops retain an average of 95% of the (neutral) genetic variation found in their wild counterparts, compared with annual fruit crops which retain about 60%.
Interspecific hybridization is very common in tree species in nature, and this ability to readily hybridize is an important trait in domestication -- once a hybrid is formed, it can become the basis for an entire new variety through clonal propagation. Thus, clonal reproduction can also result in rapid rates of change in domesticated systems because individuals with desirable traits can be reproduced exactly and extensively.
"The evolution of perennial plants under human influences results in significant changes in reproductive biology," notes Miller, "and in many cases, perennial crops have reduced fertility in cultivation."
While many annual crops were domesticated from self-compatible wild ancestors, few perennial crops were derived from selfing wild populations. Thus, domesticated perennials often encounter mate limitation barriers when one or just a few clones are planted across a geographic region. However, p
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American Journal of Botany