Advantages of Developing F sub(1) Hybrids from Native Varieties: The Case of 'Akita-Oni-Shibori' (a Pungent Japanese Radish Variety)

'Akita-Oni-Shibori' is an F sub(1) hybrid developed from the inbred fixed lines of 'Matsudate-Shibori', a native Japanese radish variety. Although 'Akita-Oni-Shibori' is an F sub(1) hybrid of related lines, it shows heterosis in its yield characteristics, such as the leaf weight, root weight, and T-R ratio, compared with its parental inbred lines. On the other hand, 'Akita-Oni-Shibori' does not show heterosis in its morphological characteristics, internal characteristics of the root, or component characteristics (content of isothiocyanate and sugar), indicating its acquisition of dominant or additive effects. Compared with the original cultivar 'Matsudate-Shibori', 'Akita-Oni-Shibori' exhibits marked uniformity in its morphological characteristics and internal characteristics of the root. In addition, high-level uniformity even in its component characteristics (content and composition of isothiocyanate and sugar) has been confirmed. These suggest that the development of the F sub(1) variety is effective for achieving the commercialization of 'Matsudate-Shibori'. On the other hand, native 'Matsudate-Shibori' has diverse genetic resources and it is necessary to continue preserving them.