Inheritance and stability of the virus-resistant gene in the progeny of transgenic sweet potato

Viral diseases of sweet potato are very prevalent and often seriously damaging to the plants. In particular, the severe strain of the sweet potato feathery mottle virus (SPFMV‐S) causes ‘obizyo‐sohi’ disease in Japan. In order to confer viral resistance against SPFMV using current biotechnology, a transgenic sweet potato has been produced, introducing hygromycin‐resistant (hpt) and SPFMV‐S coat protein (CP) genes, which have shown a significant resistance to SPFMV‐S. In the breeding programme, it is important to confirm that the viral resistance conferred in T₀ plants can be inherited by their progeny. In the present study, progeny were obtained from crosses between the transgenic T₀ and a non‐transgenic variety of sweet potato. The results showed that the CP gene was inherited by the next generation and that the stability of viral resistance was also confirmed. Thus, this production system for the virus‐resistant transgenic sweet potato is useful in practical breeding.