Relationship between net blotch (Drechslera teres) and losses in grain yield of barley in Western Australia

Abstract

Losses in the yield of cv. Dampier due to net blotch (Drechslera teres (Sacc.) Shoem.) were examined in six environments in Western Australia. Based on comparison between least diseased and most diseased treatments, there was an overall yield reduction of 21% (P < 0.05). Three models (Critical Point, Area Under Curve and Multiple Point) were used to study the relationship between net blotch infection and percentage yield loss. All models gave similar results. Because of its simplicity, the Critical Point Model based on mean net blotch infection on the top three leaves at GS 75 was chosen. The percentage yield loss in cv. Dampier was defined to be 37% of the mean diseased area on leaves 1 (flag), 2 and 3 at GS 75. This relationship is very similar to that developed earlier for scald, and a common equation for both scald and net blotch was suggested.