Abstract
Protoplasts from suspension cultured cells of Petunia hybrida. whlch had lost the ability to regenerate shoots were fused with protoplasts from leaf mesophyll cells of P.parodii which could not grow beyond a small colony stage. Fused protoplasts showed a more vigorous growth pattern than the parental protoplasts, and formed colonies which could regenerate shoots. On the contrary, parental colonies could not regenerate shoots. The hybrid nature of regenerated plants was confirmed by the color of their flower buds, their characteristic isozyme patterns and the morphology of the regenerated plants. Also, from the fact that the plants could be regenerated from hybrid cells between two different protoplasts each of which could not regenerate shoots, it was confirmed that they were somatic hybrids. Cytological analysis revealed that suspension cultured cells had 24 chromosomes in contrast with 14 chromosomes of root tip cells of both parents. On the other hand, somatic hybrid calli mostly consisted of cells which had 44 chromosomes. Somatic hybrid plants had distorted leaves and all flower buds deteriolated prematurely. These phenomena were partially attributed to higher chromosome numbers of cells of somatic hybrid plant compared to those of parental plants.
