Male Sterile Mutations of Barley Induced by lonizing Radiations and Chemical Mutagens I. Frequency, Selection and Brief Description of Sterile Mutants Induced by Gamma-ray lrradiation and Ethylene-imine Treatments on Seeds.

Abstract

From 5136 M₁ spike progenies, raised from gamma-ray irradiations and EI treatments on dormant seeds of a six-rowed barley varlety "Chlkurin lbaraki No. 1" (EXp. SD 66) and a semidwarf mutant derived from the variety (Exp. SD 68), a total of 146 progenies which segregated for sterile mutants were isolated. In Exp. SD 66, the frequency of mutated M₁ spike progenies increased with the increased dose from O.5 to 2.0% for gamma-rays and from 1.5 to 6.2% for EI. In Exp. SD 68, the dose response of the frequency was similar to that in Exp. SD 66. Relative efiiciency for induction of sterile mutation to chlorophyl mutation was quite different between gamma-rays and EI. In gamma-ray irradiation the mutation rate on M₂ plant basis was one sixth of the chlorophyl mutation rate through the doses applied and years of experiment. In EI treatment, the ratio was one third, as illustrated clearly in Fig.1, indicating that EI treatment was relatively two times more effective for induction of sterile mutation than gamma-ray irradiation.