AC Harrow Crisp


Denomination: 'AC Harrow Crisp'
Botanical Name: Pyrus communis
Applicant/Holder: Agriculture & Agri-Food Canada, Harrow
Greenhouse & Processing Crops Research Centre
2585 County Road 20
Harrow, Ontario
N0R 1G0
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: 2000-03-28
Application Number: 00-2184
Grant of Rights Date: 2003-02-28
Certificate Number: 1432

Variety Description

Varieties used for comparison: 'Harrow Delight', 'Harvest Queen', 'Bartlett' and 'Bosc'

Summary: 'AC Harrow Crisp' has a more erect growth habit than 'Bartlett' and 'Bosc'. The leaf blade of 'AC Harrow Crisp' has a more upwards attitude than the leaf blade of 'Harrow Delight', 'Harvest Queen' and 'Bosc'. 'AC Harrow Crisp' has a flatter leaf blade than 'Harrow Delight' and 'Harvest Queen'. 'AC Harrow Crisp' has larger fruit than 'Harrow Delight', 'Harvest Queen' and 'Bartlett'. 'AC Harrow Crisp' has a low amount of red over colour on the skin at maturity while 'Harvest Queen', 'Bartlett' and 'Bosc' have no over colour. 'AC Harrow Crisp' has no russet while 'Bosc' has a high amount of russet. 'AC Harrow Crisp' has a longer fruit stalk than 'Harrow Delight', 'Harvest Queen' and 'Bartlett'. 'AC Harrow Crisp' has white flesh while the reference varieties have cream coloured flesh. 'AC Harrow Crisp' is resistant to Fire Blight while 'Bartlett' and 'Bosc' are moderately susceptible. 'AC Harrow Crisp' matures later than the reference varieties except for 'Bosc' which is later maturing.


The one year old trees of 'AC Harrow Crisp' produce a medium number of side shoots and have a small bulge at the graft. The growth habit of four year old trees is semi-erect. One year old shoots have short to medium internodes and are brown on the sunny side. The shoots have a medium number of lenticels which are medium in size. The vegetative bud is elongated in shape and is not adpressed to the shoot. The colour of the young shoot is reddish-green and pubescence on the tip is weak to medium.

The attitude of the leaf blade in relation to the shoot is upwards. The leaf blade is medium in length and the length to breadth ratio is low to medium. In cross-section, the leaf blade is flat to intermediate. The base is obtuse in shape and the shape of the upper part of the leaf blade is right angled. The tip is pointed acuminate and the margins have shallow indentations which are intermediate between serrate and crenate. The midrib has very little curvature and there are no glands present. The angle of the petiole with the shoot is less than 30 degrees and the petiole is medium in length. There are no stipules present.

'AC Harrow Crisp' flowers mid-season and has a low tendency for secondary bloom. The pedicel has medium pubescence and is medium to long in length. The sepals are medium to long in length and horizontal to recurved towards the pedicel. The flower petals are touching, are short to medium in length and almost as long as broad. The base of the petal is u-shaped and the margins have strong undulation. The petal claw is short to medium in length. The stigma is positioned level with or above the anthers and anther size is large. The receptacle is slightly hollowed in shape.

'AC Harrow Crisp' has large fruit which is symmetric in longitudinal section. The shape in profile is concave to straight and the length relative to the maximum diameter is medium. The position of maximum diameter is towards the base. At maturity, the ground colour on the shaded side of the skin is yellow. There is a low amount of red over colour on the skin at maturity. The fruit has no russet. The stalk is medium to long in length and is thin to medium in thickness. The stalk is straight to slightly curved in shape and insertion is oblique. The stalk cavity is shallow. The eye is medium in size and opening at harvest is intermediate. The eye basin is medium in depth and narrow to medium in width. The margin of the eye basin is even to slightly ribbed. The sepals are convergent to upright at harvest and are short to medium in length. The fruit core is medium in diameter and the cells are elongated in shape. Core breakdown is moderate. The seeds are elongated in shape. The fruit flesh is white and the texture is fine. Fruit juiciness is weak and taste is intermediate between acid and sweet. The fruit has very few stone cells which are located throughout the flesh and are very small in size. The skin texture is medium between tender and tough and is thin to medium in thickness. Fruit aroma is mild and storage life is short to medium. 'AC Harrow Crisp' is resistant to Fire Blight (Erwinia amylovora).

Origin & Breeding History: 'AC Harrow Crisp' originated from the controlled cross between 'Bartlett' and US56112-146, made in 1972 at the Agriculture and Agri-Food Canada Research Station in Harrow, Ontario. It was selected as a hybrid seedling in 1979 and propagated by budding onto pear seedling rootstocks. In 1981, it was advanced as HW610 and testing began in 1982. Testing in regional trials was conducted from 1984 to 1999.

Tests & Trials: Tests and trials for 'AC Harrow Crisp' were conducted at the Agriculture and Agri-Food Canada Research Station in Harrow, Ontario. The trials consisted of five trees per variety, planted in a randomized complete block design. The trees were on Bartlett open pollinated rootstock. Plant Breeders' Rights data were collected from 1994 to 1999.

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