Self-fertility characterizes a plant's ability to set fruit when pollinated by its own pollen without the involvement of other cultivars. It manifests in yield stability, as such plants are less dependent on weather conditions during flowering, such as cold or rain, and the lack of insect flight. In practice, cultivars with this trait allow for the establishment of monoculture plantings without the need to select cross-pollinators.
This trait is not absolute and often exhibits instability, depending significantly on the climatic zone, the site's microclimate, and the specific weather conditions of the year. In agronomic practice, cultivars are classified by their fruit set percentage: cultivars with 20% or more are considered self-fertile, those from 10% to 20% are partially self-fertile, and those with less than 5% are self-incompatible.
During variety testing, self-fertility is evaluated in field trials by comparing the proportion of fruit formed on branches with artificial self-pollination, branches without access to insects, and control branches under free pollination. The obtained data are an important criterion for selecting a cultivar for a commercial orchard; however, experts recommend analyzing the advisability of planting pollinators even for self-fertile cultivars to realize their full biological potential.