Final answer:
The claim that turfgrass cultivars are either immune or susceptible with no partial resistance to stripe smut is false as partial resistance is indeed possible with varying levels of susceptibility among cultivars.
Step-by-step explanation:
The statement that any particular turfgrass cultivar is either immune or susceptible to stripe smut, with no partial resistance to the causal pathogen, is false. In biology, particularly in the study of plant pathology, it is well understood that resistance to diseases like stripe smut, caused by fungal or bacterial pathogens, is not always a binary condition of immune or susceptible. Instead, some cultivars may exhibit partial resistance, which provides them with a reduced level of susceptibility to the disease. This resistance can vary between different cultivars and within a specific species, and it can involve a range of physiological and genetic responses to the pathogen.