BioSample

Rubus F2 backcross to F1 of R. ulmifolius (R. rusticanus) inermis x R. thyrsiger. The tetraploid blackberry cultivar, Merton Thornless (PI 553276), was selected for EST development, because it is the source of the thornless trait in many commercially grown thornless cultivars. Young expanding leaves of 'Merton Thornless' were harvested in July, 2004, from plants growing on the North Farm of the Beltsville Agricultural Research Center. No enrichment was done of the total RNA extracted before mRNA was separated from total RNA. The cDNA library was cloned in the Gateway system (Invitrogen Corp., Carlsbad, Calif.) with the pDONR222 vector and ElectroMAX DH10B T1 Phage Resistant Cells (Invitrogen Corp.). Kanamycin was used to select colonies containing vectors. The M13F primer was used to sequence from the 5' end of 3884 clones.