Assessment of Selected Pea Genotypes Reaction to Ascochyta Blight under Field Conditions and the Impact of Disease Severity on Yield Components

The response of pea (Pisum sativum) genotypes to ascochyta blight disease and the effect of disease severity on yield components were evaluated in a 4-year trial under field conditions. Peas were inoculated with Ascochyta pinodes, the anamorph of Mycosphaerella pinodes, or with Phoma pinodella separately and with a mixture of both species. Mean infection ratings of all inoculation treatments were significantly higher compared to controls, with the highest infection for inoculation with A. pinodes. Pea genotypes significantly differed for ascochyta blight severity. The differences in extent of infection of the least and the most infected genotypes were quite consistent throughout the study. Frequencies of A. pinodes and P. pinodella isolated from diseased leaf fragments of ten pea genotypes  depended on growing season. Deleterious effects of the inoculation with Ascochyta, Phoma and Ascochyta+Phoma treatments on all evaluated agronomic parameters were observed. Greater lodging of plants in all fungi-inoculated treatments was noticed. Inoculated plants revealed decreased seed yield components as follows- number of pods and seed per plant was reduced from 12% to 19% and from 18,5 to 22%, respectively. Seed weight per plant decreased from 18% to 27,7% in comparison with controls. There were also quite large differences between pea genotypes in reduction of all yield components.