RESUMO
Pepper seeds (Capsicum annuum L.) var. B12 were mutagenized by four presoaking treatments in ten concentrations of ethyl methane sulfonate (EMS) to determine the sensitivity of the first generation (M1) to mutagens. The spectrum of mutations and induced variability for various quantitative traits, including germination, percent plant height, injury occurrence, survival ratio, first three fruits weight, and number of seeds per first fruit, were observed in the M1 generation. Our results indicated that all of the test parameters decreased with increasing EMS concentration, except for seedling injury. There were significant differences in germination ratio, LD50, plant height, percent injury, and survival ratio among the tested presoaking treatment. The LD50 was 1% EMS in seeds that were not presoaked (T1) and seeds presoaked for 12 h before treating with EMS (T3). In contrast, the LD50 was 0.5% EMS in seeds presoaked for 6 h (T2) and seeds presoaked in water for 6 h then incubated at 28°C for 12 h before EMS treatment (T4). Five dwarf plants were observed in mutagenized seeds without presoaking as compared to control seeds (at the maturity stage of the control plant).