Vernalization and photoperiod requirement of naturalized Avena fatua and Avena barbata Pott ex Link in Western Australia.
A. fatua and A. barbata plants were collected from a wide geographic range in Western Australia and tested for their temp. and daylength responses. All accessions of A. fatua required little vernalization and were therefore suited to the warm northerly areas of temperate Western Australia. Accessions of A. barbata from southerly latitudes had a strong vernalization requirement while northerly accessions did not. Response to photoperiod in A. fatua was confined to accessions from the south. All accessions of A. barbata responded to photoperiod with those from the south requiring a longer photoperiod than those from the north. A. fatua was more tolerant of frost than A. barbata. It is suggested that the different responses to temp. and daylength are largely responsible for the geographic distribution of the 2 species in Western Australia. From summary.