Assignment on breeding of pear
Course title : Breeding of fruit crops
Course No : FSC 506
Reg. No :04-2690-2015
Botanical Name :- Pyrus communis L
Chromosome No.:- 2n = 51(Triploid)
Pyrus communis, known as the European pear or common
pear, is a species of pear native to central and eastern Europe and
It is one of the most important fruits of temperate regions, being
the species from which most orchard pear cultivars grown in
Europe, North America, and Australia have been developed.
Related Species:- Pyrus pyrifolia
The commercial genotypes most commonly found today are diploids
although there are triploids (2n=51) and even tetraploids.
Commercial triploid cultivars produce little good pollen, so that
cropping in an orchard requires at least two intercompatible cultivars.
The tetraploids have aroused interest because of their extra large fruit
and leaves although generally, they yield poorly (Zielinski and
Different cultivar of Pear
Blake's Pride pear Packham's Triumph pear
Louise Bonne of Jersey
Varieties of Pear
Eight varieties of pears, from left to right, Bartlett, two Red
Bartlett varieties, Anjou, Bosc, Comice, Concorde, and Seckel.
Improvement of fruit quality.
Addition to climate adaption, disease resistance is very
important in some regions.
Early bearing and consistent cropping are important.
Adequate disease and pest resistance.
Important to develop rootstocks that induce similar size
control and precocity in the scion cultivar as Quince A
but that are more compactable winter hardy, and disease
1. Pear blossoms are white, rarely pinkish, and born in umbel like
2. The flower consist of five petals and sepals and 20-30 stamens
with anther that usually red.
3. Styles vary from 2-5 and are free but closely constricted at the
4. The ovary has 5 locules with 2 ovules per locule with a
maximum seed set obtain of ten.
Incompatibility and sterility
Hybridization and mating designs
Parental selection, progeny testing, and progeny size
Irradiation (X-rays) has been used to increase the frequency of
mutations in fruit trees .
Several kinds of mutations have been identified after irradiation in
P. communis including bloom time, blossom color, ripening time,
fruit color and growth habit .
In P. pyrifolia mutations have been induced that effected disease
resistance and self-compatibility.
At least five European and four Japanese pears have been
developed through mutation breeding.
Cell and tissue culture
Somaclonal variability and
Breeding for specific tree and production
1. Growth habit
3. Self incompatibility
1. Fruit quality
4. Skin colour
6. Flesh colour
7. Fruit size
8. Fruit shape
9. Ripening Season
Achievement and Prospects
Centuries of selection have resulted in the development of
several broadly adapted cultivars of high quality, including Bartlett,
Anjou, Comice, Bosc, Nijisseiki and Housi, that are successfully
grown in many part of the world.
Improve cold hardiness.
To reduce management cost and shorten time to bearing, pears are
being grown on dwarfing rootstocks.
High density planting.
Development of disease and pest resistant cultivars.
Resistance to Biotic and Abiotic
The resistance genes to fire blight have yet to be identified,
researchers have long known the sources of resistance and began
the breeding for fire blight resistance at Geneva in New York
State, Harrow Station in Canada and Angers in France in the
The release of such partially resistance or tolerant cultivars such
as ‘Harrow Sweet’, ‘ ‘Harrow Crisp’, ‘Blake’s Pride’, ‘Aida’ and