The reactions of tolerant varieties to PRSV isolates are also known to vary and depend on the challenge virus strain. In one study with tolerant germplasm and PRSV isolates from Jamaica, diverse reactions dependent on the challenge isolate and disease pressure were observed
in infectivity assays under greenhouse conditions (Turner et al. 2004). Useful reactions of no symptoms or mild symptom expression were obtained with tolerant cultivars from Taiwan (‘Red Lady’), Thailand (‘Thapra’) and Florida