Apple tree rootstock named ‘G.484’

Abstract

A new and distinct variety of apple tree rootstock Malus hybrid ‘G.484’ is described herein. The new variety is a dwarfing, precocious and productive rootstock that is resistant to fire blight (Erwinia amylovora) and crown rot (Phytophthora cactorum). The ‘G.484’ rootstock is useful in that it can be propagated clonally and used as a rootstock or root system for apple trees as well as for interstems of apple trees.

Claims

1. A new and distinct variety of apple tree named ‘G.484’ as herein described and illustrated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) New apple tree rootstock ‘G.484’ is illustrated by the accompanying photographs. The ages of the trees depicted in the photographs are noted below. The colors shown are as true as can be reasonably obtained by conventional photographic procedures.

(2) FIG. 1 shows a one year dormant shoot (including buds and bark).

(3) FIG. 2 shows adaxial (upper) and abaxial (lower) laminae of leaves.

(4) FIG. 3 shows fully mature fruit (interior and exterior).

(5) FIG. 4 shows a fully developed stool bed with leaves and shoots.

(6) FIG. 5 shows graft unions on finished trees.

(7) FIG. 6 shows a bundle of rooted rootstock liners.

(8) FIG. 7 shows 4-year-old trees in organic production.

DETAILED BOTANICAL DESCRIPTION

(9) The following description of apple tree rootstock ‘G.484’ contains references to color names taken from The Royal Horticultural Society Colour Chart (R.H.S.), 2001 edition. Botanical descriptions follow the Manual of Cultivated Plants (Bailey, 1949). Tree: Habit.—A self-rooted tree of ‘G.484’ is a shrub typically standing about 2-2.5 meters tall by about 2 meters wide when 7 years old. While it can be trained to a single dominant trunk, the persistent production of some root-borne suckers (i.e., new shoots emerging from below ground) means that it can evolve into a multi-trunk shrub. Liners planted in the nursery stop apical growth mid-season. Productivity.—In an intermediate field trial performed in an apple orchard Geneva, N.Y., the ‘G.484’ rootstock received the cultivar ‘Fuji’ (Malus domestica; Not patented) as the scion and was compared to the Malus domestica check rootstocks ‘M.9 EMLA’ (Not patented), ‘M.26’ (Not patented) and ‘M.7’ (Not patented). ‘G.484’ displayed similar or higher cumulative production and similar yield efficiency (kg yield/cm.sup.2 trunk cross sectional area) to all the check rootstocks. Precocity.—Scion cultivars budded on ‘G.484’ exhibit the same precocity as those budded on ‘M.26’. Fertility (fecundity).—The ‘G.484’ plant produces flowers and fruits regularly. Dormant shoots (buds and bark): Dormant mature shoots.—Color: Greyed-Red (RHS 179A) where exposed to full sunlight grading to Yellow-Green (RHS 152A) with diminished light exposure. Texture: Pubescence which gradually disappears in older tissues. Size: 35-60 cm long; generally devoid of spines. Diameter: One year shoots can be 1.2 cm at the base and 0.8 cm at the apex, varying depending on placement of shoots in the plant. Axillary buds.—Size: 4-6 mm long and 4 mm wide with evident pubescence. Shape: Obtuse, sessile, somewhat protruding. Texture: Evident pubescence. Bark on three-year-old shoots.—Color: Greyed-Orange (RHS 172A to 172B). Lenticels: Color: Greyed-Orange (RHS 163B). Size: 0.3-0.4 mm in diameter. Quantity: 3-4 lenticels per cm.sup.2. Leaves: Mature leaves.—Leaf arrangement: Alternate. Shape: Simple, flat, ovate. Size: Length: 80 mm. Width: 55 mm at the widest point. Laminae: Somewhat flat. Apex: Somewhat acuminate. Base: Nearly symmetrical rounded. Margin: Serrated, with about 3 serrations per cm. Upper surface: Color: Green (RHS 143A to 143B). Texture: Glabrous and translucent. Lower surface: Color: Yellow-Green (RHS 152D). Texture: Somewhat pubescent. Venation: Netted. Venation color: Gradation of Yellow-Green (RHS 153A) to shades of Greyed-Red (RHS 179A). Leaf poise: 25°-35° from the shoot, depending on shoot orientation. Stipules: Length: 6 mm. Width: 2 mm. Color: Green (RHS 143A to 143B) with some Greyed-Red (RHS 179A) at the base. Petioles: Diameter: 3 mm. Length: 15 mm. Texture: Somewhat pubescent. Color: Gradation of Yellow-Green (RHS 153A) to shades of Greyed-Red (RHS 179A) at the base attached to the stem. Flowers: Habit.—Flowers borne on spurs, shoot terminals, and from lateral buds on growth from previous season. Flower diameter.—40 mm. Fragrance.—None. Buds.—Location: Located on spurs and terminals; are mixed, typically producing a truss of 5 to 6 flowers and one bourse shoot. Pubescence color: Greyed-White (RHS 156D). Color of scales beneath pubescence: Grey-Brown (RHS N 199B) to Greyed-Green (RHS N 189A), depending on exposure to sun. Shape: Lateral buds are obtuse, sessile and somewhat appressed. Size: Length: 4 mm. Width: 3 mm. Habit: Buds near the base of the shoot of the previous season usually produce 3 to 5 flowers and a single short shoot; mid-shoot buds may have 2-4 flowers; and more distal buds are usually vegetative. Pedicel.—Length: 15 mm. Diameter: 2 mm. Texture: Somewhat pubescent. Color: Yellow-Green (RHS 151A). Petals.—Size: Length: 25 mm. Width: 18 mm. Shape: Spatulate. Apex: Obtuse. Margin: Smooth. Texture: Smooth. Arrangement: Intermediate. Color: Closed petals: Red (RHS 54A). Opening petals: Flowers change color (intensity) as they open. Petals on the same flower will transition from Red to White with some red striations as they open and fully expand. Open petals: White (RHS 155D) with Red (RHS 54A) striations in some of the petals. Reproductive organs.—Pistils: Length: 6 mm. Color: Yellow-white (RHS 145B). Stamens: Length: 4 mm. Color: White (RHS 155D). Anther color: Yellow-Brown (RHS 167D). Fruit: Mature fruit.—Size: Height: 40-45 mm. Diameter: 45-50 mm. Shape: Obloid. Color: Yellow-Orange (RHS 17C). Sepals: Persisting on an inset calyx. Flesh: Taste: Astringent (not meant for consumption). Color: Yellow-Orange (RHS 18A). Seed: Texture: Glabrous, smooth. Color: Greyed-Red (RHS 179A), translucent. Shape: Tear drop shape. Size: Length: 2-4 mm. Diameter: 3 mm at the widest point. Number: Generally five seed per fruit. Disease resistance: As described above, the ‘G.484’ rootstock of the present invention exhibits resistance to fire blight. The percent lesion measured after inoculation of potted liners in the greenhouse using four different strains of E. amylovora was negligible for two of the strains and moderate for the other two, indicating a specific resistance to the bacterium. The ‘G.484’ rootstock, having survived the inoculation with crown and root rot, is also considered resistant to crown and root rots caused by Phytophthora cactorum. ‘G.484’ has displayed tolerance to the replant disease complex.