Abstract
Hypocotyl explants from the seedlings of Solanum melongena, S. melongena var. insanum and their F1 hybrids showed embryogenic potential when cultured on murashige and Skoog (MS) medium supplemented with 0.5 to 2.0 mg•liter-1 2, 4-dichlorophenoxyacetic acid (2, 4-D). Solanum gilo, S. integrifolium and their F1 hybrids with S. melongena did not produce embryogenic callus even on the MS medium supplemented with 2, 4-D, indole-3-acetic acid, 3-indolebutyric acid, or 1-naphthaleneacetic acid, combined with or without 6-benzylaminopurine. Therefore, embryogenic response in Solanum through 2, 4-D appeared to be controlled by recessive gene(s), or this response was suppressed in interspecific F1 by intergenomic epistasis. Adventitious shoots were regenerated in all the Solanum species on hormone-free medium. However, only a few were produced in genotypes which showed embryogenic potential. In the histological study on somatic embryogenesis, secondary growth on embryogenic calli was observed to occur before pro-embryos developed. Sequential stages of somatic embryo development identical to those of zygotic embryo development was observed.
