Polyploidy and sensitivity to alkylating mutagens

Experiments were performed to find out whether the level of ploidy bestowed a species with any additional resistance against the lethal and mutagenic damage of alkylating agents. Seeds of 11 species of Solanum of the non-tuberous group formed the test system. Of these 2 were diploids (2n = 24); 4 tetraploids (2n = 48) and 5 hexaploids (2n = 72). Seeds of all the species were exposed to aqueous solutions of ethyl mathanesulphonate; ethylenimine ; methyl nitrosoguanidine and 1,3-propanesultone and effect of these mutagens studied through M₁ and M₂ generations.

A considerable difference in sensitivity was found even between different species of the same ploidy level and no positive relationship could be established between the level of ploidy and its sensitivity to alkylating mutagens. However, in general it has been observed that as the level of ploidy increased from diploid to hexaploid the tolerance to alkylating damage increased but not proportional to the level of ploidy. The increase in resistance varied from marginal to a highly significant level.