Abstract:
Mildew and gall mite resistance were successfully combined in R. nidigrolaria hybrids on the tetraploid level by R. Bauer, as well as mildew resistance in R. grossularia and R. nigrum cvs and gall mite resistance in R. nigrum cvs on the diploid level.
Donors for mildew resistance were R. divaricatum for gooseberries (cultivars released: Rixanta, Reflamba, Rolonda and Rokula), R. nigrum chlorocarpum and R. n. postratum for blackcurrants (cultivar Ometa).
Gall mite resistance is derived from R. grossularia, R. ussuriense and Scandinavian native species.
Artificial infestation and selection techniques have been developed at the Universities Giessen and Hohenheim (Steinborn 1982, Herr 1989). Resistance of selected clones was confirmed, in progeny tests resistant seedlings were selected.
On the tetraploid level in R. nidigrolaria combined resistance resulted from intercrossing of amphidiploid F1 parents x (R. nigrum cvs x R. divaricatum) and x(R. nigrum cvs x R. grossularia cvs) carrying mildew and gall mite resistance resp.
The cultivars Josta, Jogranda and Jostine were released.
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