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
Acer nigrum Acer nigrum Acer nigrum (black maple) is a species of maple closely related to "A. saccharum" (sugar maple), and treated as a subspecies of it by some authors, as "Acer saccharum" subsp. "nigrum". Identification can be confusing due to the tendency of the two species to form hybrids. The simplest and most accurate method for distinguishing between the two trees is the generally three-lobed leaves of the black maple versus the generally five-lobed leaves of the sugar maple. The leaves of the black maple also tend to have a "droopy" appearance. Other differences that are not as pronounced include darker,