Cytisus scoparius L plant named ‘MEI KING’

Abstract

A new variety of C. scoparius L. named ‘MEI KING’ is a dwarf shrub suitable for use a potted plant, garden shrub or ground cover.

Description

The present invention relates to a new and distinct horticultural variety of Cytisus scoparius L.

BACKGROUND OF THE INVENTION

C. scoparius L . is a woody shrub of the pulse family originally from Middle Europe and the coast of the Mediterranean Sea. Horticultural varieties of C. scoparius L . having flowers in various colors such as yellow, white, red, cream and mixed colors etc. have been bred. The majority of such varieties are erect and low to slightly tall in height, although there are some which are dwarf such as creeping varieties. Because of the drawback of the required trimming and selection, C. scoparius L . is rarely used for ornamental planting.

However, C. scoparius L . presents the advantage of vigorous growth even in unfertile wasteland, so if a dwarf variety having a wide variety of flower colors could be bred, its use as a ground cover, ornamental shrub, etc. will be possible, with a wide variety of applications to be expected.

The present inventors have developed a new dwarf variety of C. scoparius L . by a combination of mutagenesis by rapid irradiation and tissue culture technique, as described below:

1. In July 1990, pods of the original species ‘CRIMSON KING’, formed after 3 weeks of flowering, were externally sterilized in The Institute of Radiation Breeding, National Institute of Agrobiological Resources, Ministry of Agriculture, Forestry and Fisheries, Oomiya-cho, Naka-gun, Ibaraki Pref., Japan. Young embryos removed from these pods were irradiated with gamma rays of Co 60 and 100 Gy for 72 hours.

2. The young embryos thus irradiated were cultivated in an MS agar medium containing plant hormones (i.e., naphthalene acetic acid and benzyl adenine) at 25° C. for a day length of 16 hours, whereby re-differentiated plants were obtained via multi-blastema and shoots after callus induction.

3. In March 1991, the young plants sufficiently rooted in sterile medium were transferred to potting media in pots in a greenhouse, then acclimated therein, and transferred to a field.

4. Selection of a dwarf plant from the respective plants was conducted on the basis of plant height, plant width, internode length, etc. as indicators.

5. Evaluation of the practical characteristics of the resulting selected strain was carried out in the Institute of Radiation Breeding, National Institute of Agrobiological Resources, Ministry of Agriculture, Forestry and Fisheries. In reproducing selected plants, branches were selected from the Institute of Radiation Breeding in June; cuttings each approximately 10 cm long were planted in sterilized river sand or vermiculite; and rooted plants were cultivated in a mist room. After April 1993, the evaluation was conducted in Ashigara Farm of Meiji Seika Kaisha Ltd. in Kayama, Odawara City, Kanagawa Pref., Japan, and the present variety, which was judged to be a promising dwarf plant based on the examination results obtained up to May 1997, was finally selected.

The present ‘MEI KING’ variety has a cup-shaped spreading form and extreme dwarfism with a mature height of 35 cm. Leaf attachment is sparse with many flowers borne from the base of branches, the flowers being deep red and larger than those of the original variety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the variety ‘MEI KING’;

FIG. 2 shows the variety ‘MEI KING’ at flowering time; and

FIG. 3 shows the original variety ‘CRIMSON KING’.

BOTANICAL DESCRIPTION

The original variety ‘CRIMSON KING’ is erect in form, while ‘MEI KING’ is prostrate, with spreading and cup-shaped form. The original variety is tall, with a plant height of about 160 cm, while ‘MEI KING’ is very dwarf, having a mature plant height of about 35 cm. The internode length is 0.9 cm, which is shorter than in the original variety. The leaf length is 11 cm, which is shorter than that of the original variety, and the petiole length is also shorter. The leaves are sparse as compared to the original variety. The standard petal is 21.5 mm in length and 19.1 mm in width, and the wing petal is 20 mm in length and 9.2 mm in width, and these are similar to those of the original variety.

The shape of a floral bud is long elliptic and its color is deep red. When it blooms, the entire surfaces of both the adaxial and abaxial sides of a standard petal uniformly turn to a deep red color. The adaxial face of a wing petal is deep red while the abaxial face of the wing petal is light yellow. The standard petal and the wing petal of the present variety are comparatively larger than those of the original variety. The overall size of the flower is also larger, and the color of the flower deeper, in comparison to the original variety. Filaments are yellow and curvedly projected from petals with yellow anthers at the tips thereof. Pistils are hidden behind petals and invisible from the outside. The flower emits a fragrance characteristic of leguminosae. The total bloom period lasts approximately one month, and the prime of bloom is 7 to 10 days, which is a most valuable term for a decorative plant. Sexual fertility is poor, and few flowers become fertilized. Vegetative propagation by cuttings is required for reproduction.

The distinctive characteristics of ‘MEI KING’ have been examined in plants cultured at Ashigara Farm in the period 1993-1997 as described above, according to the examination standards based on the Japanese Seeds and Seedlings Law. The characteristics of ‘MEI KING’ are set forth below, as compared to the variety ‘CRIMSON KING’.

Characteristic	’MEI KING'	’CRIMSON KING'
Plant vigor	weak to medium	medium to strong
Plant form	flat circle to flat	elliptic
Plan height	low (35 cm in 5-year	tall to very tall
	mature plant)	(160 cm)
Direction of	spreading to greatly	erect to spreading
branching	spreading
Internode length	short (0.9 cm)	medium (1.1 cm)
Leaf composition	mixture of single	mixture of single
	(one leaflet) and	(one leaflet) and
	compound (two or	compound (two or
	three leaflets) in	three leaflets) in
	varying ratio	varying ratio
Leaf shape	long elliptic	long elliptic
Color of leaf	green	green-deep green
Shape of leaf tip	sharp to obtuse	sharp to obtuse
Shape of leaf edge	smooth	smooth
Warp of leaf	convexly warped to	convexly warped to
	flat	flat
Length of leaf	short to medium	medium to long
	(11.0 mm)	(12.3 mm)
Width of leaf	medium (3.0 mm)	medium (3.5 mm)
Length of petiole	short (5-10 mm)	medium
Leaf	sparse	medium
Color of new shoots	light red	light red
Pubescence of new	little	little
shoots
Shape of flower bud	long elliptic	long elliptic
Size of flower bud	medium	medium
Size of flower	medium to large	medium
Color of standard	red	red
petal (surface)	JHS: 0415	JHS: 0415
	RHS: 53C	RHS: 53C
Color of standard	red	white to yellow
petal (back)	JHS: 0415	JHS: 2202
	RHS: 53C	RHS: 18C
		19C
		20D
		158A
		162D
		164D
Color of wing petal	red	red
(surface)	JHS: 0415	JHS: 0415
	RHS: 53C	RHS: 53C
Color of wing petal	white to yellow	white to yellow
(back)	JHS: 2202	JHS: 2202
	RHS: 18C	RHS: 18C
	19C	19C
	20D	20D
	158A	158A
	162D	162A
	164D	164D
Length of standard	short to medium	short
petal	(21.5 mm)	(20.1 mm)
Width of standard	medium	medium
petal	(19.1 mm)	(17.5 mm)
Length of wing petal	short (20.0 mm)	short (19.6 mm)
Width of wing petal	narrow (9.2 mm)	narrow (9.1 mm)
No. of stamen	medium	medium
Branch sprouting time	seasonal, late	late
	sprouting begins
	around March
Flowering time	average, begins	average
(70-80%)	mid-April to mid-May
Leaf falling time	average, begins around	average
	October and completed
	mid-winter
Disease resistance	no susceptibility to any
	serious disease, but
	susceptible to
	inchworm
Culture	can survive in poor
	soil if well drained,
	but root damage if
	poorly drained.

The ‘MEI KING’ cultivar has not been observed under all possible environmental conditions to date. Accordingly, it is possible that the phenotype may vary somewhat with variations in the environment, such as temperature, light intensity, and day length.

Claims