ABSTRACT
In our experiments we dealt with the bacterial soft rot of potato caused by Erwinia species. In the experiments back cross progenies (BC1, BC2, BC3 and BC4) of Solanum brevidens + Solanum tuberosum somatic hybrids produced by the Potato Research Centre, Keszthely were tested to the infection of E. carotovora ssp. carotovora (Eca) and E. chrysanthemi (Echr). All together 29 BC genotypes pre selected from several hundred breeding lines based on their preferred agronomical appearance and virus resistance characters as well as 2 varieties (White lady and Hópehely) as controls were involved into the experiments. Tuber slices from each genotype were artificially infected after 2 and 5 months of harvest with bacteria suspension (Eca strain D3, and Echr strain CHR 1492) and incubated at 27 degrees C with 100% relative air humidity for 48 h before evaluation. Dry matter and starch content of tubers were determined right before the tests. Volume of rotted tuber tissue was determined in mm3 and used for comparison of the level of resistance or susceptibility of the genotypes. Relationship between the reaction to the bacteria strains and dry matter/starch content was examined also.