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Dena is a grapevine variety heterozygous for the mutant Gibberellic Acid Insensitive
(GAI) allele that confers dwarfness and continuous flowering. Dena vines are dwarf, with
internodes less than one-third the length of related non-dwarf plants. Dena vines
preferentially produce inflorescences in place of tendrils and consequently the vines are
continuously flowering. When cultivated in a greenhouse, Dena vines flower throughout
the year. Dena vines produce the pistillate flower type, with non-functional male flower
parts. The pistillate flowers of Dena vines are fertile and develop into seeded grapes
when cross pollinated. The pistillate flowers of Dena make the development of new
populations of dwarf vines very easy, because hybridization can be accomplished without
the need for emasculation. Dena vines can be grown to flowering in a 750 ml pot. In
comparison to the Pixie grape variety, Dena vines grow more quickly, although the
internodes are still very short and Dena vines are considered true dwarf vines (as are
Pixie grapevines). Dena vines are easier to cultivate in the greenhouse than Pixie
because of faster growth and Dena vines are more resistant to common greenhouse pests and
diseases than are Pixie vines.
Dena resulted from selection of a dwarf seedling in a population derived from controlled hybridization of the grape rootstock 187G (pistillate flowered seed parent, unpatented) with the dwarf grape variety Pixie (perfect flowered pollen parent, unpatented), Vitis vinifera L. The original Dena vine grew from a seed planted in 2009 and the cross pollination that created the seed was made on May 6, 2008. Dena grapevine was tested by USDA ARS with the selection number PC08124-5.
Dena grapevine originated from a cross of two non-patented grapevine varieties. The seed
parent is the rootstock 187G and the pollen parent is the dwarf grapevine Pixie. Both
the rootstock 187G seed parent and the dwarf grapevine Pixie pollen parent are free from
intellectual property restrictions and encumbrances. No proprietary information or
inventions are needed to fully utilize the Dena grapevine.
The Dena grapevine variety will be useful for the development of new populations of GAI
dwarf grapevines for genetics and breeding research. Grapevine pollen can be applied to
Dena grapevine flowers on vines growing in a greenhouse and the resulting population
should be expected to segregate 1:1 dwarf:non-dwarf grapevines. The dwarf seedlings of
Dena would be expected to begin flowering in 90 to 100 days, with mature fruit 90 – 120
days later. Thus, Dena enables rapid development of GAI dwarf grapevine populations that
flower and fruit very rapidly and with small space requirement for genetics and breeding
research. Because Dena vines are pistillate flowered, no emasculation is needed for the
production of hybrid seeds, which makes using Dena as a parent in population development
very simple. |
