Tree Fruits – Pears

This document reviews the major pear cultivars recommended for Ontario in the Pear Cultivars factsheet. In it, the term cultivar is any horticulturally recognized and named type or sort that can only be maintained through vegetative propagation or the use of selected breeding lines and seed sources. Spring frost during bloom is a threat in most regions of Ontario. To ensure fruiting, pears should be grown in areas that have some moderating affect from one of the Great Lakes or on a site with a slope that allows for good air drainage.

Cultivars and requirements are described below.

Growth Climate Zones

Pear cultivars below are recommended for hardiness zones 5b, 6a, 6b, 7a and 7b. We suggest that the cooler the climate zone the later the harvest date of the pear variety to be planted should be chosen. In Pear Cultivars, Table 2, Average Date of First Harvest for Pear Cultivars, the average dates of the first commercial harvest of pear cultivars at the University of Guelph, Department of Plant Agriculture, Vineland are shown. Actual harvest dates and performance characteristics in any region may differ from dates above and general cultivar characteristic descriptions below.

Pollination Requirements

Under Ontario conditions, commercial pear cultivars are considered self-unfruitful; consequently, cross-pollination with a suitable pollenizer cultivar is required. Our experience with Barlett in Ottawa, is that heavy fruit set on isolated trees may occur if proper pollinating insects are present.

Honeybees, bumblebees and large flies are the major agents responsible for transferring pollen among plum cultivars. Like plums, pear blossoms have low sugar content (10%) and may suffer competition with flowers for pollenizing insects.

Cross-incompatibility (the inability of pollen from one cultivar to set fruit on another) is seldom found among diploid pear cultivars. The only exception of importance is the cross-incompatibility of Bartlett pollen with Seckel.

Bosc is an ideal pollenizer for Bartlett and is adequately pollinated by Bartlett as well. Anjou is a satisfactory pollenizer for Bartlett.

AC™ Harrow Crisp tends to be a poor pollinator and will not consistently pollinate Bartlett, but Bartlett will pollinate AC™ Harrow Crisp to a limited extent. In pollination studies in 2000, good fruit set was obtained when AC™ Harrow Crisp was self-pollinated or pollinated by HW 614, with limited fruit set when pollinated by Bartlett. AC™ Harrow Crisp pollinated Bosc, Anjou, Flemish Beauty and AC™ Harrow Gold, with limited fruit set on Bartlett and Clapp’s Favourite.

AC™ Harrow Gold pollination of Bartlett has been variable. In some years, it does not appear to pollinate Bartlett, while in other years, good fruit set has been obtained with AC™ Harrow Gold pollen. In pollination studies in 2000, AC™ Harrow Gold pollinated Bartlett, Bosc, Anjou and Flemish Beauty. Bartlett does appear to consistently pollinate AC™ Harrow Gold. Bartlett, Bosc and AC™ Harrow Crisp pollinated AC™ Harrow Gold in recent pollination studies.

Cultivars

Below are cultivars from Table 1, Recommended Pear Cultivars. For pictures of fruit see the Pear Photo Gallery. Name colour code are:  green for first choice due to the best characteristics of late maturity, fruit properties, and disease tolerance of trees; orange for second choice for trees that are slightly less than optimal but still excellent; and red for not recommended because of one or more severe limitations. Names uncoloured in black are considered undistinguished but may still be planted as good trees. Cultivar characteristics that have factored into the colour coding are shown in bold. Cultivars are:

  • Anjou. When well grown and properly handled, Anjou is a good quality dessert pear of long storage and shipping life. The skin is light green and, unlike Bartlett, does not change from green to yellow upon maturity. The flesh is very mild, aromatic and fine-textured. Lack of fruit-set is a common weakness of this cultivar. The tree is more fire blight resistant than the Bartlett cultivar.
  • Bartlett. This cultivar comprises about 75% of total pear production in North America. In Ontario, it is the leading cultivar by hectares and number of trees. Bartlett trees are productive and adaptable to a wide range of soils and climatic conditions. Careful orchard management is required to avoid fire blight and still obtain satisfactory yield and quality. Pick fruit at a pressure of 6.8-8.0 kg (15-19 lb) as measured on a pared surface of the fruit using a pressure tester with an 8 mm diameter tip plunger. Store fruit immediately at -1° C (30° F) until a week before it is used. Rapid removal of field heat and prompt cooling of harvested pears are associated with successful long-term storage. The maximum storage period for Bartlett at -1° C is about 2½-3 months.
  • Bosc. A high quality, flavourful, dessert winter pear with excellent keeping and shipping quality. Bosc is widely grown as a dessert pear in the western U.S. It is an important and well-adapted pear in milder regions of Ontario. The trees are very productive, come into bearing late and are susceptible to fire blight. They are difficult to train due to their leggy growth habit and lack of branching.
  • Clapp’s Favorite. An attractive, large, productive, good quality pear maturing 2 weeks ahead of Bartlett. Pick fruit when they attain sufficient size, at least 10 days before full maturity. Failure to harvest fruit at the proper stage of maturity results in rapid core breakdown. The tree is vigorous, bears early and regularly, does well on heavy soils and is very cold hardy. It is susceptible to fire blight, however.
  • Flemish Beauty. The hardiest cultivar available for colder districts of Ontario. Flemish Beauty is susceptible to scale and fire blight. The tree is very productive and vigorous. The fruit are high in quality, but require careful timing of harvest to obtain full flavour and freedom from breakdown.
  • French Bartlett (Doctor Jules Guyot). An old cultivar that was introduced to North America around 1885. Guyot resembles Bartlett in shape and colour, but tends to be larger and rougher. Trees come into bearing early, but breakage of branches is sometimes a problem. Guyot is not as good in quality as Bartlett but is quite acceptable. It ripens with or just after Clapp’s Favorite.
  • Giffard. An early summer pear of good quality and medium size. When picked at the correct stage of maturity, it keeps well. It is suitable only for limited commercial planting as an early roadside and farm market cultivar.
  • AC™ Harrow Crisp (formerly HW 610) (Parentage: Bartlett x US56112-146). It is a very attractive pear with red blush on smooth yellow skin. The cream-white flesh is smooth, grit-free and firm even when fully ripe, with a mild sweet flavour. The fruit matures at the end of Aug. or early Sept., about the same time as Bartlett. It can be picked over a 2-week period. Early picked fruit can be stored for about 2 months, but storage life is reduced with later picking. If kept too long or picked too late, it will deteriorate internally without external signs. Fruit size on unthinned trees is slightly larger than Bartlett. It has a good to very good rating for fresh fruit quality. When processed as pear halves, it has maintained its integrity, received good to very good ratings, and has been included in a CanAdapt pear trial. The tree is medium in size, conical and upright, annually productive and hardy. The tree has excellent resistance to natural fire blight infections (9.5 rating compared to Bartlett reading of 4.2), similar to Harrow Sweet and Harvest Queen. Following inoculation, lesion development may extend to about 15% of current season’s growth. Precocity of AC™ Harrow Crisp is similar to Bartlett, trees coming into production about 4 years after planting. AC™Harrow Crisp is protected under the Plant Breeders Rights Act (application number 00-2184).
  • AC™ Harrow Gold (formerly HW 616) (Parentage: Harvest Queen x Harrow Delight). Fruit are picked about 10 days before Bartlett, between Harrow Delight and Harvest Queen. An attractive yellow fruit, with good size (larger than Harvest Queen, similar in size to Bartlett), smooth skin, fine texture, very good flavour with a good balance between sweetness and acidity, and exceptionally juicy. The fresh fruit quality of AC™ Harrow Gold is rated similar to Bartlett. As with many other early season pears, the fruit will not store for very long (probably no more than 4-6 weeks) in common cold storage, but it is excellent for roadside stands. This cultivar has received good to very good processing ratings and has been included in the CanAdapt pear trial. AC™ Harrow Gold has excellent resistance to natural fire blight infections (9.6 rating); however, in some years following inoculation with the causative organism, lesions have developed which have extended to about 25% of current season’s growth. Precocity in a second test planting appears to be similar to that of Bartlett. AC™ Harrow Gold is protected under the Plant Breeders Rights Act (application number 00-2185).
  • Harrow Delight. The fruit, smaller than Bartlett, are greenish yellow in colour with a red blush. The cultivar ripens 2 weeks before Bartlett and is resistant to fire blight. Pick fruit while still green; otherwise, it drops heavily. Harrow Delight is pollen-compatible with Bartlett, Bosc, Anjou and Harvest Queen.
  • Harvest Queen. The fruit resemble Bartlett in shape, colour, texture and flavour, but are smaller than Bartlett. Thinning will improve fruit size and reduce the tendency toward biennial bearing. Harvest Queen ripens 1 week before Bartlett and is as resistant to fire blight as Kieffer. Fruit hangs well on the tree and size will improve with delayed picking. Harvest Queen is pollen-compatible with Bosc, Anjou and Harrow Delight, but not Bartlett.
  • Harrow Sweet™ (PBR #0572). Fruit size is comparable to Bartlett, colour is yellow with a red blush at maturity, and taste is sweet, juicy and excellent. The cultivar ripens 3½ weeks later than Bartlett and trees show good resistance to fire blight. Harrow Sweet is reciprocally pollen-compatible with Bartlett.
  • Kieffer. Strictly a canning pear of poor quality and a poor pollenizer for major pear cultivars grown in the province. Although it is highly fireblight resistant, most Kieffer plantings have been removed and planting Kieffer is not advised in Ontario.
  • Seckel. A very high-quality, attractive, productive, small, late pear. The core tends to break down in the middle near harvest. In Ontario it has been used for pickling. Seckel should be planted only in home gardens and for special markets in Ontario.

Rootstock

Pear rootstocks belong to several species of pear (Pyrus) and a few are even in different genera (Cydonia, quince; Crataegus, hawthorn; Sorbus, mountain ash). In the past, Bartlett pear seedlings (Pyrus communis) have been used exclusively in Ontario as the standard rootstock for pear orchards.

Standard Rootstocks

  • Bartlett Seedling: produce vigorous trees and are adaptable to a wide range of soil and climatic conditions but they are all susceptible to fire blight.

Semi-dwarfing to semi-vigorous rootstocks

    • Old Home x Farmingdale Clones: are productive and do not show excessive suckering and are all highly resistant to fire blight and winter injury.
      • OHXF 40. Although it has only limited testing, early observations indicate that growth control with early production can be achieved.
      • OHXF 69. Trees from this rootstock may produce a tree approximately 70%-80% the size of a standard pear seedling. Reports from the west coast indicate that it may be somewhat susceptible to growing one-sided root systems.
      • OHXF 87. This rootstock is the highest producer of the Old Home series. It has demonstrated the ability to set fruit early and bear heavily. If allowed to crop heavy, it will give the grower a tree smaller than Bartlett Seedling.
      • OHXF 97 Is roughly the same size as Bartlett seedling trees but highly precocious. It is resistant to fire blight, pear decline, winter hardy and compatible with most cultivars.

Dwarfing rootstocks

Pear growers have been limited to Quince selections (Cydonia oblonga) for use as dwarfing rootstocks. Table 3, Graft compatibility of pear cultivars on Quince rootstocks, lists the pear cultivars, which are compatible and incompatible, when grafted directly on Quince.

Guidelines for orchard management of this rootstock are found in Pear Cultivars. Varieties used are:

  • Quince A. This rootstock is reasonably winter hardy (to -26° C.), tolerates excess soil moisture but not standing water, restricts vegetative growth of the pear scion cultivar, and induces fruit production at a younger age. It is not unusual to have fruit on 2 yr-old trees in the nursery or orchard.
  • Quince C. This is another clonal selection but has not proven to be as winter hardy as Quince A. It is more dwarfing than Quince A and very susceptible to leaf-spot fungus in the nursery.

This Series

References

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