Blackcurrant material from the gooseberry ("Ribes grossularia"), the red currant ("Ribes rubrum") and the flowering currant ("Ribes sanguineum"). The resulting offspring were further back-crossed to "R. nigrum". Cultivars produced include 'Tisel' and 'Tiben' in 2000 and 'Ores', 'Ruben' and 'Tines' in 2005. Further cultivars 'Polares' and 'Tihope' are being tested. Since 1991, New Zealand has become an important centre for research and development, as its temperate climate is particularly suitable for cultivation of the crop. Breeding programmes are concentrating on yield, large fruit size, consistency of cropping and upright habit. In North America, there is a need for this fruit to
Allium nigrum to 60 cm long and 2.5 cm across. Later the leaves become reflexed. Scapes are smooth and round in cross-section, 80–100 cm tall. The scape carries a dense umbellate inflorescence with star-like flowers up to 9 mm across; tepals white with a green midevein; anthers purple or yellow. The ovaries are black-green (but flushed with red in the Levant) in anthesis, but green when younger or following anthesis. Type species of Subgenus (Section) "Melanocrommyum". Molecular evidence suggests that "A. nigrum" is a polymorphous species consisting of several infraspecific groups. Alliances: Allium nigrum alliance: "Allium nigrum" L. and "A. multibulbosum" Jacq.