Development of a visual infection phenotype scale for barley seedlings infected with Cochliobolus sativus and the use of multispectral radiometry in disease assessment of barley

ccurate disease assessment is necessary to evaluate the seedling infection response and to estimate crop loss in barley. To identify infection responses in barley to Cochliobolus sativus, a 1-9 numerical rating scale was developed based on disease symptoms displayed on a diverse collection of barley germplasm. Nine infection phenotypes (IPs) were classified on the basis of lesion size and type. IPs 1 and 2 had minute round necrotic lesions with no chlorosis and indicated a highly resistant host response. IPs 3 and 4 consisted of short (;A multispectral radiometer was tested for its ability to assess disease severity and estimate crop loss. The multispectral radiometer data were highly significant in estimating yield ;In contrast, visual disease assessments and area under the disease progress curve values had low correlation...