Abstract
Pollen grains with Bz-gene of maize were exposed to gamma-rays in single or two equal fractions and crossed to recessive stocks to observe mutations to bz F1 seeds. A linear dose-mutation frequency relationship was confirmed up to 3000R in the sum of whole and partial mutations expressed as bronzy aleuron color. While the frequency of partial mutations did not show any significant difference by single or fractionation treatment, that of whole mutations was significantly decreased by fractionation with an interval period of 120 minutes or less. No temperature effect was found by holding at 5-30°C. It is concluded that the mutagenic action of gamma-rays was reduced by dose-fractionation probably due to certain recovery events taking place under experimental conditions applied.
