In vitro attempts to overcome the cross-incompatibility between Vaccinium corymbosum L. and V. elliottii Chapm.

Seed was readily obtained from V. corymbosum zygotes using embryo rescue techniques, even when embryos were cultured at proembryonic stages. Best in vitro seed development was obtained when ovules were cultured attached to placental tissues. Successful fruit and seed development in culture occurred only when the fruit was cut longitudinally or when the basal portion of the fruit was removed previous to plating. Addition of various vitamins, amino acids, and growth regulators to the nutrient medium did not increase seed production. Attempts to rescue hybrid embryos from V. croymbosum (tetraploid) x V. elliottii (diploid) crosses by in ovulo and in ovary culture gave a few presumably hybrid seed, but at a rate no greater than when normal crossing procedures are used.