SJM15

Apple

Variety Description

Varieties used for comparison: 'Malling 26' and 'Ottawa 3'

Summary: 'SJM15' is an apple rootstock variety which has a higher tendency to produce suckers than 'Ottawa 3' and less pubescence on the upper half of dormant one-year-old shoots than either reference variety. The dormant one-year-old shoots of 'SJM15' are thinner and more flexible with larger lenticels than those of 'Ottawa 3'. The growing tip of the shoot is greenish yellow for 'SJM15' while it is white for 'Malling 26' and red for 'Ottawa 3'. Pubescence of the upper side of the shoot tip leaves is sparse for 'SJM15' while it is dense for 'Malling 26'. The shoot tip leaves of 'SJM15' are bronze green while those of 'Malling 26' are pale green and those of 'Ottawa 3' are green. 'SJM15' has larger leaves than 'Malling 26' and smaller leaves than 'Ottawa 3'. Pubescence on the lower side of the leaves is absent for 'SJM15' while it is dense for 'Malling 26' and sparse for 'Ottawa 3'. Bud burst occurs earlier for 'SJM15' than either reference variety. 'SJM15' produces fruit which is symmetrical in side view and smaller than that of 'Malling 26' whose fruit is asymmetrical in side view. The fruit of 'SJM15' has weaker ribbing than that of 'Ottawa 3'. 'SJM15' has a smaller eye than the reference varieties. The eye basin of 'SJM15' is absent while it is medium deep for 'Malling 26' and very shallow to shallow for 'Ottawa 3'. The fruit stalk of 'SJM15' is thicker and shorter than that of 'Ottawa 3' and thinner and longer than that of 'Malling 26'. 'SJM15' has a very strong bloom of the skin while it is weak for 'Malling 26' and weak to moderate for 'Ottawa 3'. 'SJM15' has a greater amount of skin over colour than both reference varieties. The skin over colour for 'SJM15' is red to dark red while it is orange to pink for 'Malling 26' and pink to red for 'Ottawa 3'. The fruit flesh for 'SJM15' is yellowish while it is white for 'Malling 26' and cream for 'Ottawa 3'.

Description:

TREE: end use as clonal rootstock, low tendency to produce suckers, poor root anchorage, dwarfing to very dwarfing effect

BASAL SHOOTS IN STOOL BED: intermediate vigour, few, straight

DORMANT ONE-YEAR OLD SHOOT: sparse pubescence on upper half, strong shine of bark, moderate flexibility, many large lenticels, predominantly reddish brown on sunny side
LATERAL BUD: small to medium in size, pointed tip, adpressed position relative to axis of shoot, small to medium sized support
GROWING TIP: greenish yellow

SHOOT TIP LEAVES: straight in cross section, sparse pubescence on upper side, bronze green on lower side
LEAVES: no lobes, medium in size, acuminate apex, serrate margin, moderate glossiness on upper side, no pubescence on lower side, weak anthocyanin colouration of veins, medium green upper side, absent to very weak anthocyanin colouration of upper side, medium to large stipules

FLOWER BUD: medium to dark pink at full balloon stage
FLOWER: single type, green pedicel
PETAL: ranging from almost round to oblong and broad ovate in shape, overlapping margins, purple red (RHS 58A) blush along margins on upper side, purple red (RHS 58A) irregular patterns on lower side

FRUIT: very small, flat to flat globose in shape, symmetric in side view, very weak to weak ribbing, crowning at distal end absent or weak when present, small eye with closed to half open aperture, persistent calyx in mature fruit, medium to long sepals, variable spacing at base of sepals, either raised or flat distal end in relation to fruit surface, no eye basin, thin and long stalk, medium deep and narrow stalk cavity
FRUIT SURFACE: smooth, very strong bloom, no translucency, yellow ground colour, high amount (60-80%) of red to dark red over colour, solid to washed out over colour, low amount of russet positioned around stalk cavity, small to medium sized lenticels, slightly to intermediately prominent lenticels
FRUIT IN CROSS-SECTION: yellowish flesh, absent or very weak core line, aperture of locules closed

SEED: brown at maturity, ranging from globose and conical to obtuse in shape

REACTION TO INSECTS: resistant to woolly apple aphid (Eriosoma lanigerum Hausmann)

Origin & Breeding History: 'SJM15' originated from a cross between Malus baccata (L.) Borkh. variety 'Nertchinsk' and 'Malling 9', a clonal selection of Paradis Jaune de Metz. The cross was conducted at Agriculture and Agri-Food Canada (AAFC) in Manitoba in 1960. This breeding program was terminated and the resulting seedlings were transferred in 1971 to the AAFC Apple and Rootstock Breeding Program in Saint-Jean-sur-Richelieu, Québec for further evaluation. 'SJM15' was selected in 1984 based on its winter hardiness, ease of propagation, pest resistance and disease resistance. It was planted in 1997 in several replicated trial plots in Frelighsburg and also at two grower sites in Québec.

Tests & Trials: The test and trial for 'SJM15' was conducted within stool beds and self rooted orchards at l'Acadie Research Sub Station of Agriculture and Agri-Food Canada in l'Acadie, Quebec during the summers of 2000 and 2003. The trial included 3-4 root stocks of each variety and 4 self rooted trees of the candidate variety, 5 self rooted trees of reference variety 'Malling 26' and 8 self rooted trees of reference variety 'Ottawa 3'. All colour characteristics were determined using the 2001 Royal Horticultural Society (RHS) colour chart and measured characteristics were based on ten measurements except for the measured leaf characteristics of 'Malling 26', which were base on 8 measurements.

Comparison table for 'SJM15' with reference varieties 'Malling 26' and 'Ottawa 3'

Dormant one-year-old shoot: thickness (mm)

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Apple: 'SJM15'

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Apple: Reference variety 'Ottawa 3'

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Apple: Reference variety 'Malling 26'