Effect of barley yellow dwarf virus (BYDV) on barley: A precise assessment of reductions in yield components under variable disease severities

Understanding the effects of barley yellow dwarf virus (BYDV) on crop agronomic traits and yield performance helps breeders balance their selection criteria and farmers decide if pesticides should be applied to control aphids that distribute the virus. To precisely assess the deterioration of different agronomic traits and yield components caused by different levels of BYDV infection, seeds of a BYDV-sensitive barley variety cv. RGT Planet were space sown in a field plot with 10 cm between seeds and 20 cm between rows under two consecutive years. When BYDV symptoms were shown, plants with different levels (0 - 5) of BYDV infection were tagged. For accurate comparisons, the neighbouring non/less-infected plants were also tagged. At maturity, different agronomic traits and yield components were measured on those tagged plants. Results showed a strong linear correlation between BYDV severity and the performance of agronomic traits and yield components. The yield reductions ranged from 30% for the least affected (score of 1) to 90% for the severely affected (score of 5). Our research confirmed previous findings that BYDV seriously affects crop yield and the prediction of yield loss due to BYDV infection should use the percentage of plants with different BYDV symptoms.