Soil-borne cereal mosaic virus: agronomic performance of durum wheat cultivars as predicted by virus concentration and symptom severity evaluations of different dates.

Two-hundred and fifteen durum and hexaploid wheat cultivars have been so far tested in Italy for resistance to Cereal soilborne mosaic virus (CSBMV) in field trials carried out in eight diverse seasons. Because CSBMV-reactions were evaluated in fields with natural inoculum sources of CSBMV by comparing the agronomic performance each cultivar, as well as on the basis of ELISA readings and symptom severity evaluations made on various dates each season, it has been possible to classify the reaction to CSBMV of practically all the above cultivars quite precisely, and to estimate the mean effects on grain yield and other plant caracters associated with different symptom severity scores and relative ELISA values. We have compared - separately for each of the fifteen trials carried out in eight seasons - all the correlations between the CSBMV assessments made on different dates and each of the agronomic characters examined, i.e. grain yield, test weight, kernel weight, plant height and heading date.