Frequency and spectrum of chlorophyll-deficient mutations in rice after treatment with radiation and alkylating agents

Abstract

Three varieties of rice were treated with gamma rays and two alkylating agents EMS and DES, alone and in combinations, with a view to finding out the frequency and spectrum of chlorophyll mutations in relation to the genotype and the nature of the mutagen. Chlorophyll mutation frequency was enhanced with increasing dose but dropped at very high doses (doses that induced over 90% seedling lethality in M 1). The fall was attributed to either the increased mutated sector and diplontic selection after exposure to very high doses or relatively high resistance of some of the seeds. Among chlorophyll mutants in M 2 induced by radiations as well as alkylating agents, the albina type formed the majority class. EMS induced a significantly higher proportion of albinas than did gamma rays.