An assessment of the genetic integrity of micropropagated raspberry and blackberry plants

Abstract

In vitro clonal propagation of small fruit species has been one of the most broadly exploited approaches in biotechnology. However, the most critical aspect of this propagation technology has been the maintenance of genetic fidelity of tissue culture-raised plants. In the present study, three techniques were deployed in the assessment of genetic fidelity of micropropagated plants (TC plants) of blackberry cultivar Cacanska Bestrna' and raspberry cultivar 'Meeker' in the second year after planting in the open field, in comparison to plants originating from the standard planting material (ST plants). Flow cytometry analysis deployed to estimate the DNA ploidy level and relative nuclear DNA content in TC and ST plants revealed no significant differences in nuclear DNA content between plants of different origin. Chromosome counting in root/shoot tip meristems also showed a normal tetraploid chromosome number (2n = 4x = 28) in TC blackberry plants and a normal diploid chromosome number (2n = 2x = 14) in TC raspberry plants. Polyacrylamide gel electrophoresis of peroxidase (POX) extracted from the leaf tissue revealed no differences in POX profiles between TC and ST plants either. The results obtained in this study verify the suitability of micropropagation by axillary branching for commercial exploitation in blackberry and raspberry.