Induced mutagenesis in the genus Atropa

Various doses of X-rays (10-60 kR) and thermal neutrons (1 to 7.5 x 10sub(nth)sup(13) cmsup(-2)) were applied to the seeds of two Atropa species. LD50 dose for X-rays and thermal neutrons was 40 kR and 7.5 x 10sub(nth)sup(13)cmsup(-2) respectively. Seeds of the two species did not show any significant differences in radiosensitivity when subjected to X-rays or thermal neutrons. Microspectral photometry revealed that the G2 DNA content in both the species was about 45 arbitrary units. Effect on quantitative characters was studied in M2 generation. Following irradiations mean values for plant height, number of leaves per plant and alkaloid content did not increase significantly as compared to control, whereas variability increased for the characters studied. However, in 7.5 x 10sub(nth)sup(13)cmsup(-2) treated populations, increase in the plant height was observed in both the species. No chlorophyll mutations appeared in X-ray treated progenies. Appearance of xantha mutants was conspicuous feature of the thermal neutron treated progenies in A. acuminata. (author)