Effect of spot-type net blotch (Drechslera teres (Sacc.) Shoem) infection on barley yield in short season environment of northern cereal belt of Western Australia

Abstract

The effect of spot-type net blotch (Drechslera teres (Sacc.) Shoem.) on yield was studied in fourteen field experiments located at two sites over seven years in the area where the disease occurs; the northern cereal belt of south-west Western Australia. An overall reduction of 26% in grain yield occurred associated with spot-type net blotch infection. The yield losses varied depending upon season, date of sowing and cultivar. Disease was found to reduce 100 grain weight and number of ears/m2, but number of grains/ear were not affected. Regression analysis supported the above negative effect of disease on yield in general, but in a few cases disease and yield were positively correlated. The Area Under Curve (AUC) model was considered most appropriate and percentage yield loss (L) was estimated as L = 0.0233 AUC. Using this relationship, potential losses in yields of cvv. Beeeher and O'Connor were estimated to be 34% and 29%, respectively. The application of this relationship is suggested to be limited to short season environments similar to the northern cereal belt of Western Australia. A need to understand factors which modify the yield response to this disease is highlighted.