American Journal of Botany 43(10): 794-801 (Dec 1956)
The Effect of Various Trisomic Conditions in Datura stramonium on Crossability with Other Species
Kathleen Cole

SUMMARY
Certain trisomics of Datura stramonium promoted the production of hybrid embryos in crosses with D. ceratocaula I and II. Pollinations with D. ceratacaula II were more efficient in embryo production and development than those with D. ceratocaula I, but pollen germination and pollen-tube growth are not the controlling factors in hybrid formation since fertilization takes place in all cross combinations. There is a high mortality of embryos in early stages. The 2n + 17-17 trisomic used in the crosses was unique in the production of (a) 100 per cent capsules with embryos, (b) the greatest number of embryo-containing seeds per capsule, and (c) hybrids capable of being grown to maturity. The primaries 2n + 19-20 and 2n + 23-24 and the secondary 2n +11-11 also increased considerably the number of seeds containing embryos. The two ends of the extra chromosome in the primary trisomics are not similar in their effect on embryo production. The reduced vigor of the trisomic female parent increased, from 40 to 86, the percentage of embryo-containing seeds per capsule in crosses of 2n + 17-17 x D. ceratocaula II. Very large 3n cells and cells with giant nuclei containing 4 times the normal number of chromosomes were observed in the endosperm in certain D. stramonium trisomics crossed with both D. ceratocaula types.

Blakeslee: Trisomic Daturas (1922)


CybeRose note: I wonder whether this could have played a role in the evolution of the Rosaceae (Maloideae).

Chromosome Changes in Evolution and Adaptation

Breeding with mutants