Variety traits

Pear Parthenocarpy

Pyrus communis L.

The ability of pear trees to form fruit without fertilization or in the absence of cross-pollination, serving as an adaptation mechanism to stabilize yields under adverse weather conditions.

In the reference 20 varieties crop European pear, where this is mentioned in the description.

To evaluate a cultivar's propensity for parthenocarpy, the Pcompl index is used, calculated by the formula Pcompl = Ps + Pa/F, where Pa is the percentage of fruit set in isolated flowers, Ps is the percentage of fruit set during natural self-pollination with gibberellin, and F is the average number of leaves per inflorescence.

Pear cultivars are classified into those with no (0.00–0.40), low (0.41–0.80), moderate (0.81–1.90), and high (above 1.91) propensity for parthenocarpy. A high expression of this trait ensures crop formation even when flowers are damaged by frosts or when pollinator insect activity is low.

Parthenocarpic pear fruits are most often seedless or contain seeds without embryos. Cultivars with a pronounced ability for parthenocarpy, such as Williams, Conference, and Beurré Bosc, are considered more reliable for cultivation in regions with an unstable climate during the flowering period.

General information about the subject — on the page Parthenocarpy.

Sources7

Varieties of European pear mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.