Influence of radiation and chemically induced sterility on mutation frequency and spectrum in barley

Abstract

Seeds of NP104 were treated with y rays, ethyl methanesulphonate (EMS) and N-nitrosomethyl-urea (NMU). EMS caused less reduction in fertility and a higher mutation frequency than y rays. NMU produced the highest reduction in fertility and the highest mutation rate. The M_.t spikes were grouped into five fertility classes and the progeny of individual spikes was screened for the presence of chlorophyll mutations. In the low fertility classes, y rays and EMS produced the lowest mutation rates and with improvement in fertility there was an increase in the mutation frequency. The NMU-treated spikes showed a different pattern, with a high mutation rate in the low fertility classes, the highest rate being at 21-40% fertility. The mutation rate declined with further increases in fertility.