The Journal of Heredity 75:62-66. 1984. Expression and inheritance of

parthenocarpy in 'Severianin ' tomato ABSTRACT: The expression of parthenocarpy in the tomato cultivar Severianin is faculta-tive, producing seeded and/or seedless fruits depending on the environmental conditions. The genetics of this facultative parthenocarpy in Severianin was verified as being con-trolled by a single recessive gene, pat-2. Expressivity of pat-2 is strong in environments unfavorable for normal pollination and fertilization of flowers in tomato; for example, high night and day temperatures In midsummer In Urbana, Illinois. Plant breeders should find this trait useful as an adjunct system to promote fruit setting in tomato, particularly in stress environments where It has the ability to form normal but seedless fruits. Selection for parthenocarpy without the labor-intensive procedure of emasculation is efficient when segregating populations are grown in temperature stress environments. This parthenocar-pic gene may be associated with determinate growth habit and/or earllness through pleiotropic effects and not genetic linkages. No genetic linkages were detected with aw, c, ps, u, and y