An Experimentally Produced Secondary Polyploid in the Genus Nicotiana
1932 Volume 4 Issue 1 Pages 38-45
Details
1932 Volume 4 Issue 1 Pages 38-45
The origin of a new fertile 30II derivative type from the hybrid between N. rustica (24II) and N. paniculata (12II) is described.
This type from a taxonomic point of view would be considered a distinct species.
The pairing is variable, as many as five quadrivalents being formed. As a result the fertility, though good, is not comparable to that of the parental species.
Selfing of hybrids diploid for one species and haploid for another is suggested as a general method of origin of higher chromosome numhers other than those in a polyploid series.
Certain difficulties in the way of explaining the origin of higher chromosome numbers by way of species crossing are discussed.
