Central - Tobacco Research Institute, Rajahmundry, (A.P.)
1Present address: Department of Genetics, University of Wisconsin, Madison, Wisconsin, U.S.A.
Interplant morphological and cytological variation was observed in the F1 as well as the colchiploid population of the cross, N. megalosiphon X N. glutinosa. Elimination of one or two chromosomes at a time from different F1 plants and 4 to 5 during the ontogeny of the colchiploids was inferred. It was shown that elimination of different chromosomes from different plants was the cause for the morphological variation in the progeny.
The possibility of interspecific hybridization in the ancestry of the genus Nicotiana leading to such a somatic chromosomal instability and its role in the production of aneuploid series both at 12- and 24-paired level has been discussed. It is suggested that some of the present day species of section suaveolentes (subgenus petunioides) may carry in them some common components for somatic instability.
