Interactions Between Avena and Puccinia Species. I. The Wild Hosts: Avena barbata Pott Ex Link, A. fatua L. A. ludoviciana Durieu

Abstract

Populations (21) of wild oats collected throughout New South Wales [Australia] were assessed at the seedling stage for their reaction to 4 races of the oat crown rust pathogen (P. coronata) and 4 races of the oat stem rust pathogen (P. graminis avenae). Populations from northern New South Wales were significantly more resistant and more diverse in their infection response to P. coronata than were populations from southern New South Wales. Differences in the distribution of resistance to P. graminis avenae were considerably less marked. For populations of A. fatua there was a non-significant increase in resistance in the north. For populations of A. barbata, on the other hand, there was no difference in the average level of resistance between northern and southern populations. No differences were detected in the average response of populations of any of the 3 wild oat species to infection by P. coronata. For P. graminis avenae this was also true for populations from the north of the State. The importance of intra-population diversity in infection response as a means of reducing disease is discussed.