Heavy-ion beam-induced sterile mutants of verbena (Verbena×hybrida) with an improved flowering habit
Sterile mutants of <i>Verbena</i>×<i>hybrida</i> were isolated at high frequency from nodal cultures of developed plants irradiated with heavy-ion beams. Sixty four <i>in vitro</i>-cultured nodes of fertile cultivars 'Temari Sakura' (FS), 'Temari Coral Pink' (FC) and 'Temari White' (FW) were irradiated with 1 to 10Gy of <sup>14</sup>N-ion beam (1890MeV). Lateral shoot development of FS, FC and FW was not affected by irradiation with up to 10Gy. After open-pollination, shoots with inflorescence forming unenlarged ovaries were selected and propagated several times by cutting. Shoots were grown to flowering and the selection process for isolating stable sterile mutants was carried out by the same method. Finally, one mutant out of 104 FS lateral shoots (5Gy), one mutant out of 115 FC shoots (5Gy) and 3 mutants out of 108 FC shoots (10Gy) were successfully isolated. With the exception of sterility all these mutants showed normal morphology. Two sterile mutants SS and SC, which were isolated from 5Gy-irradiated FS and FC, respectively, were characterized by their flowering habits. These two mutants grew well, had a larger number of inflorescences, and a better longevity compared with their parental cultivars. These results show that heavy-ion beam irradiation is an excellent tool for isolating sterile mutants without alterations in others important traits at a high frequency. In addition, the characterization of SS and SC indicated that they have different sterile phenotypes: male and female gametes of SS are non-functional, in contrast, SC exhibits self-incompatibility, which results in mutants unable to produce seeds.
- Plant biotechnology
Plant biotechnology 25(1), 91-96, 2008-03-01
Japanese Society for Plant Cell and Molecular Biology