Inheritance patterns of parthenocarpic fruit development in highbush blueberry (Vaccinium corymbosum L.)

Forty-one half-sib families (>3000 individuals) segregating for parthenocarpic fruit production were evaluated under field conditions. Within these families, ≈280 parthenocarpic individuals were identified. In general, three categories of segregants were observed: normal-seeded types, small/low-seeded types, and parthenocarpic types. Inheritance patterns suggested that the trait is recessive, but did not fit simple tetrasomic recessive or incomplete dominance models. Lack of fit may be attributable to environmental interactions or incomplete penetrance of this trait. Further evaluations are underway with small/low-seeded types with the expectation that offspring of these plants may express the trait at higher frequencies than in F₁ x F₁ crosses. The reduced vigor in many of the parthenocarpic segregants suggests that this germplasm will be most useful, initially, in improving fruit quality in the intermediate expression types, which have better fruit set and reduced seed development.