AbstractA group of 69 rice cultivars with diverse degrees of resistance to rice blast disease (at least in a qualitative sense) was chosen for a detailed study of some components of race non‐specific resistance, i.e. relative disease efficiency, latent period, and sporulation capacity. Large differences amongst cultivars were found. The overlapping of the normal curves for the qualitative reaction and the components of race non‐specific resistance point out the difficulties of rapid screening for blast resistance by simple observation in the field. One approach to overcome these difficulties could be to use component(s) analysis in the evaluation of rice germplasm to identify parents or progeny having the attributes of race non‐specific resistance.