We have developed more than 100 crosses in Brassica oleracea involving CMS lines using line x tester mating design, but some of the resultant test cross progenies depicted that The particular cross combination for a specific trait resulted Highest positive significant Heterosis (BPH and MPH) among all the crosses but the SCA effect of that particular cross is non significant or very poor. Why it so or What kind of gene action is involved or any other reason.