RESISTANCE TO RHOPALOSIPHUM-PADI (HOMOPTERA, APHIDIDAE) IN HORDEUM-VULGARE SUBSP SPONTANEUM AND IN HYBRIDS WITH HORDEUM-VULGARE SUBSP VULGARE

Accessions of Hordeum vulgare subsp. spontaneum, the progenitor of cul tivated barley, were screened in field and glasshouse trials for resis tance to the aphid Rhopalosiphum padi. A few selected lines were furth ermore hybridized with a modern barley variety and the resulting popul ations evaluated. High levels of resistance were found among some of t he 'spontaneum' accessions resulting in lower aphid growth rates (maxi mum reduction 57%). Segregation patterns among siblings in F2 populati ons were continuous, indicating the presence of several genes with pos sibly additive effects. The usefulness of H. vulgare subsp. spontaneum for breeding aphid resistant barley is discussed.