| 'Russet Burbank', the most important potato in North America, was described as a putative periclinal mutation from 'Burbank' and has not parented outstanding cultivars. The current study aimed to: (1) investigate the present chimeral status of NB 'Russet Burbank' based on tuber periderm phenotype, (2) determine if yield and/or processing characteristics of NB 'Russet Burbank' could be improved through selection of intraclones, (3) determine whether pre-selected somaclones had sufficient variation in protein content (crude (CP), total soluble (TSP)), or resistance to Phytophthora infestans (US-8) to select for, and (4) examine long-term stability in protein content. Somatic embryogenesis technology was used to regenerate intraclones of the NB clone of 'Russet Burbank' potato. Approx. 800 intraclones were regenerated and field-tested from 2005 to 2007. At harvest, we selected somaclones with the greatest yield compared with NB 'Russet Burbank' control. Following storage, tubers of selected clones were tested for processing quality characteristics and protein content. Late blight resistance was examined in the greenhouse for 2 years.;Results showed that most intraclones had tubers with russet periderm. About 4% of intraclones had non-russet tubers and 21% had patchy periderm. Presently, NB 'Russet Burbank' is not organized as periclinal chimera (Nassar et al. 2008). From 2-9% of intraclones had superior reducing sugar characteristics. Two promising somaclones with good yield and reducing sugars were selected by industry for further evaluation. Molecular characterization is now needed for advanced somaclones with improved processing features. Somatic embryogenesis technology generated sufficient somaclonal variation for potential improvement of NB 'Russet Burbank' (Nassar et al. 2009a). One advanced somaclone had greater CP content than control in 2008. One somaclone had lesser TSP content for 3 consecutive years and 7 somaclones exhibited reduced TSP content for 2 consecutive years compared with control (Nassar et al. 2009b). This is the first study to report inter-seasonal variation in protein content in potato. A full characterization of protein content in advanced somaclones is needed. Most intraclones showed resistance to P. infestans (US-8) similar to controls; field study is required. In conclusion, these studies underline the advantages of using somaclonal technology and its suitability in potato improvement programs. |
