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Partial resistance (PR) (Puccinia triticina) in wheat cultivars is a form of incomplete host genetic resistance characterized by a susceptible infection type or a compatible host-pathogen interaction. Despite of this susceptible reaction, the diseased tissue remained less than that of the highly susceptible genotypes, thus the disease progress or development in PR cvs. is retarded. Although, all the tested cvs. were uniformly inoculated with the two races TKTT and PKTT, under the favourable greenhouse conditions, PR components varied significantly between PR cvs. and the highly susceptible ones. The partially resistant cvs., Giza 168, Sakha 94 Sakha 95 and sids-12, characterized by their capacity to restrict both colony and pustule sizes (mm²), reduce a pustule eruption rate (%) and consequently prolonged latent period (LP) of both races, under study. In contrast, the highly susceptible cvs., sids-1, Gemmeiza-7 and Giza 139 (check), showed large colony and pustule sizes, high rates of pustule eruption and shorter times (days) of LP, at seedling and adult plant stages. A close and high correlation was found between each of the four PR components in the greenhouse and FRS (%), r-value and AUDPC in the field, as indicated by the high significant correlation coefficients. Thus, these components of resistance could be considered as the promising characteristics and a best selection criterion for screening and selecting partially resistant (PR) genotypes. [ABSTRACT FROM AUTHOR]