Radiation Induced Chlorophyll Mutations in Rice

Chlorophyll mutations comprising of albina, xantha, virescent and rara types like striata, chlorina and lutescent occurred in n₂ gegeration after treatment of seeds with X-rays, P³² and S³⁵, and in M₃ generation after chronic gamma irradiation of plants of three varieties of winter rice. Within the range of dosages applied, the mutation rate in general increased with increase in radiation dosages excepting in P³² and S³⁵ when dosages above 8 ^c/seed produced a decline in mutation rate. A comparison of the mutagenic effects of X-rays, P³²and S³⁵ revealed that P³² and S³⁵ were more mutagenic than X-rays. Again, P^3S was found to be more mutagenic than S³⁵.

The mutation spectrum varied after treatment with different ionizing radiations. Compared to P³² and S³⁵, X-rays produced relatively more of albina and virescent tan dess so fantha. S³⁵ 5nduced more eare eype mutataons than X-rays and P³². Albina was more frequent than xantha or virescent tfter exposure of plants to a number of dosages of Co⁶° gamma rays. Irrespective of the mutagens used, albina occurred in maximum frequency followed by virescent, xantha and rare types.