Evaluation of cytoplasmic segregation in somatic hybrids of Nicotiana: tentoxin sensitivity

Abstract

Tentoxin inhibits chloroplast development, and sensitivity to the toxin is cytoplasmicaily inherited in Nicotiana. Somatic hybrids between the albino mutant of N. tabacum Su/Su and the wild species N. nesophila, N. glauca, and N. otophora were analyzed for tentoxin sensitivity. N. tabacum is resistant to tentoxin whereas the wild species analyzed here are all sensitive. The response to tentoxin indicates the parental chioroplast type present in somatic hybrids. Chloroplast segregation did not appear to be random in these hybrids, but in most cases the chioroplast type present in sexual hybrids was the only type found in somatic hybrids. The segregation of parental chloroplast types after protoplast fusion in these and other reported somatic hybrids is discussed.