Denomination: 'HW623'
Botanical Name: Pyrus communis
Applicant/Holder: Agriculture & Agri-Food Canada, Vineland
Research Farm - Vineland
4902 Victoria Avenue North, P.O. Box 6000
Vineland, Ontario
L0R 2E0
Breeder: David Hunter, Agriculture & Agri-Food Canada, Vineland, Ontario
Agent in Canada: Agriculture & Agri-Food Canada
Office of Intellectual Property and Commercialization
6000 C&E Trail
Lacombe, Alberta
T4L 1W1
Tel: (403) 782-8126
Application Date: 2009-04-29
Application Number: 09-6638
Grant of Rights Date: 2010-11-25
Certificate Number: 3973
Grant of Rights Termination Date: 2028-11-25

Variety Description

Varieties used for comparison: 'Bosc', 'Harrow Sweet', 'AC Harrow Crisp' and 'Bartlett'

Summary: The predominant colour on the sunny side of the one-year old shoot of 'HW623' is brown purple whereas it is orange brown on 'Harrow Sweet' and 'Bartlett' and medium brown on 'AC Harrow Crisp'. The trees of 'HW623' begin flowering late whereas they flower early to mid-season on 'Harrow Sweet' and mid-season on 'Bartlett'. The position of maximum diameter on the fruit of 'HW623' is clearly towards the calyx whereas it is clearly to slightly towards the calyx on 'Bosc' and 'AC Harrow Crisp' and in the middle to slightly towards the calyx on 'Bartlett'. The sides of the fruit of 'HW623' are concave whereas they are concave to straight on 'Harrow Sweet', 'AC Harrow Crisp' and 'Bartlett'. The area of over colour of the fruit of 'HW623' is small whereas it is absent on 'Bosc', medium sized on 'AC Harrow Crisp' and very small on 'Bartlett'. The over colour of 'HW623' is orange red whereas it is light red on 'AC Harrow Crisp' and pink red on 'Bartlett'. There is no russetting around the eye basin, on the cheeks and around the stalk attachment of 'HW623' whereas it is very large on 'Bosc'. The stalk of 'HW623' is oblique to right-angled in relation to the axis of the fruit whereas it is straight to oblique on 'Bosc' and 'Bartlett' and oblique on 'Harrow Sweet' and 'AC Harrow Crisp'. At harvest, the area around the eye of 'HW623' is slightly ribbed whereas it is smooth on 'Bosc' and 'Harrow Sweet'.


TREE: medium to strong vigour, medium to strong branching, semi-upright habit, begins flowering late, late maturity for consumption

ONE YEAR OLD SHOOT: straight to wavy growth, medium to long internode, brown purple on sunny side, many lenticels
VEGETATIVE BUD: acute apex, adpressed in relation to the shoot, medium sized bud support
YOUNG SHOOTS: strong to very strong anthocyanin colouration of growing tip, sparse pubescence on upper third

LEAF: outwards to downwards attitude in relation to shoot, large length/width ratio, right-angled base, right-angled apex, short to medium length pointed tip, bluntly serrate margin, shallow incisions, medium curvature of longitudinal axis
STIPULES: present, short to medium distance from basal attachment

FLOWER: mainly on spurs, medium to long bud, stigma positioned above stamens
SEPALS: long, spreading in relation to corolla
PETALS: overlapping, medium to large, circular, rounded base, short claw

FRUIT: long to very long, large maximum diameter, large length/diameter ratio, position of maximum diameter clearly towards calyx, medium to large size, slightly asymmetric to strongly asymmetric in longitudinal cross section, concave profile of sides
SKIN: yellow ground colour, small amount of orange red over colour, no area of russet around eye basin, on cheeks or around stalk attachment
STALK: thin to medium in thickness, medium curvature, oblique to right-angled attitude in relation to axis of the fruit, absent or very shallow stalk cavity
EYE BASIN, AT HARVEST: converging sepals, shallow to medium depth, medium to broad, slightly ribbed relief around eye
FLESH: very fine texture, medium firmness, juicy to very juicy
SEED: elliptic

DISEASE RESISTANCE: resistant to moderately resistant to fireblight (Erwinia amylovora)

Origin & Breeding History: 'HW623' arose from the controlled cross of 'Harrow Sweet' and 'HW605' made in 1979 at Agriculture and Agri-Food Canada Research Station in Harrow, Ontario. It was selected as a hybrid seedling in 1988 and propagated by budding on pear seedling rootstocks. Trees were planted in an evaluation orchard at the Harrow Research Centre in 1993 and in November, 1999, trees in this orchard were relocated to the Agriculture and Agri-Food Canada Research Farm at Jordan Station. This selection was advanced and tested in regional trials in cooperation with the Western Ontario Fruit Testing Association beginning in 1994.

Tests & Trials: The tests and trials for 'HW623' were conducted during the 2006-2009 growing seasons at the Jordan Farm of Agriculture and Agri-Food Canada Research Centre in Vineland, Ontario. The trials consisted of a minimum of 4 trees per variety spaced 3 metres apart and 4.5 metres between rows. The trees were grafted on seedling rootstock and were originally established during the 1998-1999 growing season.

Comparison tables for 'HW623' with reference varieties 'Bosc', 'Harrow Sweet', 'AC Harrow Crisp' and 'Bartlett'

Leaf length (cm)

  'HW623' 'Bosc' 'Harrow Sweet' 'AC Harrow Crisp' 'Bartlett'
mean 8.8 7.1 7.1 6.3 6.5
std. deviation 1.1 1.3 1.2 0.8 0.7

Length of fruit stalk (mm)

  'HW623' 'Bosc' 'Harrow Sweet' 'AC Harrow Crisp' 'Bartlett'
mean 30.8 45.6 32.9 35.0 25.2
std. deviation 5.4 9.2 5.2 7.7 4.9

Click on image for larger view
Pear: 'HW623' (left) with reference varieties 'Bosc' (top centre), 'AC Harrow Crisp' (top right), 'Harrow Sweet' (bottom centre) and 'Bartlett' (bottom right)

Click on image for larger view
Pear: 'HW623' (left) with reference varieties 'Bosc' (centre, left), 'Harrow Sweet' (centre), 'AC Harrow Crisp' (centre, right) and 'Bartlett' (right)

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