Garden pea Varietal Susceptibility to Mycosphaerella pinodes and its Effect on Yield Components of Single Plants

The susceptibility of 21 garden pea genotypes to Mycosphaerella pinodes was evaluated in a two years study with inoculation under controlled conditions and in field experiments. The tested genotypes differed significantly in their susceptibility to seedling foot rot and leaf and stem blight caused by M. pinodes under these tests. Average scores of leaf infection in laboratory testing were higher comparing to the degree of infection in field conditions with inoculation. The genotypes which were rated susceptible to foliar infection were also susceptible to stem infection, with the severity of stem infection being much lower. No significant correlation was obtained between foliar symptoms severity and seedling foot rot necrotic index for garden pea genotypes. Deleterious effects of the inoculation with M. pinodes in field experiments on all yield components of pea plants parameters were observed. The pathogen caused 14.6% reduction of number of pods per plant, 17.3% reduction of number of seed per plant, 23.5% reduction of seed weight per plant and 7.8% decrease of 1000 seed weight in comparison with protected controls. There were also quite large differences between the years of testing as well as among pea genotypes in reduction of yield components. Genotypes Mieszko and Jurand showed the lowest reduction of seed weight per plant and appeared to be more tolerant to M. pinodes among the tested. Overall, five of tested genotypes (Kadona, ZIF 2401, Juko Nike and Deko) were considered as moderately susceptible. The remaining were either susceptible or highly susceptible (Cud Kelwedonu, Pionier, Markus, Kosynier, Duet and Hetman). The obtained results will be useful for breeders in selecting the components for a crossing programme.