SJM44

Apple

Variety Description

Varieties used for comparison: 'Malling 26' and 'Malling 9'

Summary: 'SJM44' is an apple rootstock variety with wavy basal shoots while those of the reference varieties are straight. 'SJM44' has weak pubescence on the upper half of the dormant one-year old shoots, whereas both 'Malling 26' and 'Malling 9' have very strong pubescence. The lenticels on the shoots are very numerous and small for 'SJM44' and they are less numerous and large for 'Malling 26'. The leaves of 'SJM44' have weak to medium pubescence on the lower side, whereas 'Malling 26' has dense pubescence and 'Malling 9' leaves are glabrous on the lower side. Self rooted trees of 'SJM44' produce white flower buds with pink along the margins, whereas 'Malling 26' buds are medium pink. The flowers of 'SJM44' are larger than those of 'Malling 26'. 'SJM44' produces very small fruit, compared to those of 'Malling 26' which are medium in size. 'SJM44' fruit are globose in shape with a raised eye (calyx) and yellow ground colour, whereas 'Malling 26' fruit are flat in shape, have a medium to deep eye basin and a green-yellow ground colour. The overcolour of 'SJM44' is pink, while it is orange to pink for 'Malling 26'.

Description:

TREE: low suckering tendency, poor root anchorage, dwarfing

BASAL SHOOTS IN STOOL BED: intermediate vigour, medium number, wavy

DORMANT ONE-YEAR OLD SHOOT: weak pubescence on upper half, shiny bark, weak to medium flexibility, very many small lenticels, reddish brown colour on sunny side
LATERAL BUD: small, pointed tip, slightly held out relative to axis, small bud support
GROWING TIP: red

SHOOT TIP LEAVES: concave to straight in cross section, very weak pubescence on upper side, green on lower side
LEAVES: dark green, no lobing, medium size, oriented outwards, cuspidate apex, serrate margin, weak to medium glossiness, moderate pubescence on lower side, weak anthocyanin on veins, absent to very weak anthocyanin colouration on upper side
STIPULES: medium size

FLOWER BUD: white (in full balloon stage) with medium pink along the margin
FLOWERS: single, green pedicel
PETALS: white, very large, circular shape, overlapping margins

FRUIT: very small, globose shape, symmetric in side view, weak ribbing, no crowning at distal end, eye is medium to large and closed, persistent calyx, medium to long sepals, sepals overlapping, no eye basin (raised eye)
FRUIT STALK: thin, long, stalk cavity narrow and shallow to medium in depth
FRUIT SURFACE: smooth, yellow ground colour, low to medium amount of pink overcolour, overcolour is washed with streaks and flecks, very low amount of russet around stalk cavity, lenticels small and slightly prominent
FRUIT IN CROSS-SECTION: yellowish flesh, no core line, closed locules

SEED: brown at maturity, normal shape

REACTION TO INSECTS: Resistant to woolly apple aphid (Eriosoma lanigerum)
REACTION TO DISEASES: Resistant to scab (Venturia inaequalis)

Origin & Breeding History: 'SJM44' originated from a cross between Malus baccata (L.) Borkh. variety 'Nertchinsk' and 'Malling 9', made in 1960 at Agriculture and Agri-Food Canada, Morden Manitoba. The selection was made in 1971at AAFC in St-Jean-sur-Richelieu, Quebec based on criteria including vigour, winter hardiness, disease resistance, dwarfing effect and the effect on the tree branch structure.

Tests & Trials: Tests and trials for 'SJM44' were conducted at the L'Acadie Research Sub Station of Agriculture and Agri-Food Canada, St-Jean-sur-Richelieu, Quebec. The trial included 3 to 4 root stocks of each variety and 4 self rooted trees of each variety. The stoolbed was planted in 2000 and self rooted trees of the varieties were planted in an orchard in 1999 and allowed to develop into fruiting trees. Measurements and observations were recorded in 2005. Measured characteristics were based on 10 measurements.

Comparison tables for 'SJM44' with reference varieties 'Malling 26' and 'Malling 9'

Dormant one-year old shoots: thickness (mm)

Dormant one-year old shoot: length of internode (mm) (at middle third of shoots)

Flower: diameter (cm)

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Apple: 'SJM44'

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Apple: Reference variety 'Malling 9'

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Apple: Reference variety 'Malling 26'