We performed field trials to assess levels of changes in intrinsic properties and resistance against soft rot of the potato cultivar ‘Irish Cobbler’ upon the introduction of the Shiva-1 gene. Each five lines, transformed with Shiva-1 gene controlled by the PAL5 promoter (P) and by the CaMV 35S promoter (E) were evaluated in the field. In based on evaluation of 10 defined morphological characteristics, all the transgenic clones of both lines proved to be true to type. When five agronomic characteristics were taken into account as well, all the transgenic lines except E8 were considered to be true to type. According to the result of northern blot analysis, seven (P1, P3, P4, P6, E10, E12, and E16) transgenic clones could be distinguished clearly from corresponding untransformed clones. But in three lines (P8, E5, and E8), no hybridization signal was detected. There seems to be positive correlation between the levels of resistance to soft rot and the transgenic expression at mRNA levels in P lines. But in the case of E lines, however, there doesn’t seem to be any correlation between the levels of disease resistance and mRNA expression