In vitro mutation induction of raspberry species (Rubus) using gamma ray irradiation
摘要
Raspberry species produce highly nutritious fruits that are used for fresh consumption and frozen and processed products, such as jellies, juices, jams, and desserts. Efforts have been made to improve raspberry yield and fruit quality using conventional breeding. However, the narrow genetic diversity in raspberry species limits the progress of raspberry breeding. In this study, in vitro leaf and petiole tissues of three raspberry cultivars, ‘Amethyst,’ ‘Joan J,’ and ‘Polana,’ were irradiated with gamma rays at 0, 25, 50, or 100 Gy for mutation induction. In vitro shoots were then regenerated from the gamma ray–irradiated tissues in woody plant medium (WPM) supplemented with 20.0 g·L−1 sucrose, 6.5 g·L−1 agar, 200.0 mg·L−1 polyvinylpyrrolidone (PVP), and 1.0 µM thidiazuron (TDZ). Regenerated shoots were rooted in one-half MS medium containing 0.5 µM naphthaleneacetic acid (NAA). Rooted plants were first grown in the greenhouse and the survived raspberry plants were planted in the field. Results showed that gamma ray irradiation significantly decreased the shoot regeneration of the three raspberry cultivars; however, three raspberry cultivars responded differently to gamma ray irradiation in shoot regeneration. Of which ‘Joan J’ and ‘Amethyst’ were more tolerant to gamma ray irradiation than ‘Polana.’ More shoots were regenerated from leaf tissues than from petiole tissues. Morphological variations in leaf, cane, plant structure, and fruit were observed in the field. This research demonstrates that in vitro mutation induction using gamma ray irradiation could be a useful tool to develop genetic materials that have potential for breeding and germplasm improvement of raspberry and other Rubus species.