Articles
NEW RESULTS OF BREEDING RIBES NIDIGROLARIA: AMPHIDIPLOID SPECIES HYBRIDS BETWEEN BLACKCURRANT AND GOOSEBERRY
Since 1949 crosses followed by polyploidization have been made between cultivars and wild species of black-currant and gooseberry to combine resistance with useful plant and fruit characteristics.
Selfings of primary amphidiploids showed the expected complex heredity of resistance and growth character.
The fertility, however, was low.
Progeny tests of seedlings derived from open pollination led to the same results, except in a few cases.
These F2-plants showed a sufficient self-fertility, heterosis and the desired combination of resistances which proved that they must have been derived from two different genetic types of primary amphidiploids.
One of the two hybrids originated from x (R. nigrumx mildew-resistant R. divaricatum) and the other from x (R. nigrumx R. grossularia), resistant to white pine blister rust.
These fertile F2-hybrids represent "double-hybrids" with increased heterozygosity.
The first cultivar of the new species hybrids Ribes nidigrolaria was introduced by Bauer in 1977 under the name of "Josta".
Today there are already 2000 seedlings of about 70 selected F2- and F3-clones derived from 12 genetically different primary amphidiploids of the two crossing lines mentioned above.
There is a variation with respect to fruit characteristics and ripening.
To select cultivars suitable for mechanical harvesting is one of the main aims today.