FURTHER STUDIES ON RESISTANCE OF BARLEY VARIETIES TO THE APHID <i>RHOPALOSIPHUM PADI</i> (L.)

Abstract

Seventy-eight of three hundred and thirty-eight barley varieties tested in the greenhouse showed some resistance (antibiosis or tolerance) to the aphid Rhopalosiphum padi (L.). When the 78 varieties were retested m the field, 29 demonstrated both antibiosis and tolerance. No varieties tested were completely immune to the aphid. Fourteen varieties which had shown resistance in field tests in 1961 were retested in 1962, and all continued to demonstrate both antibiosis and tolerance. About 9.1 per cent of 474 varieties tested in 1961 or 1962 from the Canadian Genetic Stock of Barley may be regarded as source material for breeding for resistance to R. padi.