EVALUATION OF INTERSPECIFIC CROSSING EXPERIMENTS IN FACULTATIVELY APOMICTIC BLACKBERRIES (RUBUS SUBGEN RUBUS) USING DNA-FINGERPRINTING

A series of interspecific crossing experiments in Rubus was evaluated with DNA fingerprinting to assess the proportion of apomictic vs sexual seed set. A total of 71 seedlings and their putative parents were thus analyzed by hybridization of HaeIII-digested DNA samples to a minisatellite DNA probe derived from the M13 phage. Of the offspring derived from non-hybridogenous seed parents, only about 10 % appear to emanate from sexual seed set. On the contrary, offspring derived from pollination of hybridogenous plants were in 6 cases out of 10 sexually derived. Pollen stainability with cotton blue was also investigated and could, though to a more limited extent, be used as an indicator of reproductive mode. Taxonomic treatment of Rubus and other apomictic plant groups would clearly benefit from more data on reproduction and dispersal, which may be obtained by DNA fingerprinting.