Pyrus communis, known as the European pear or common pear, is native to central and eastern Europe and southwest Asia. The document discusses the breeding of pear, including its botanical information, genetic resources, varieties, breeding objectives, floral biology, breeding systems, and achievements and prospects. The key points are: Pears have a chromosome number of 2n = 51 and are triploid; breeding objectives include improving quality, disease resistance, early bearing, and consistent cropping; methods used in pear breeding include hybridization, mutation breeding, and biotechnology.

2. Assignment on breeding of pear
Course title : Breeding of fruit crops
Course No : FSC 506
Submitted by:
Pawan Nagar
M.SC.(Horti.)
fruit science
Reg. No :04-2690-2015

3. pear
Botanical Name :- Pyrus communis L
Family:- Rosaceae
Origin:- Europe
Chromosome No.:- 2n = 51(Triploid)

4. Introduction
 Pyrus communis, known as the European pear or common
pear, is a species of pear native to central and eastern Europe and
southwest Asia.
 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
Pyrus pashia
Pyrus serotina
Pyrus salicifolia

5. Ploidy levels in Pear
1.Triploid (2n = 51)
2. Tetraploids (2n = 68)
3. Hexaploid (2n = 102)

6. Genetic Resources
 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
Thompson 1967).

7. Different cultivar of Pear
Blake's Pride pear Packham's Triumph pear
Clairgeau pear
Louise Bonne of Jersey
pear

8. Varieties of Pear
 Eight varieties of pears, from left to right, Bartlett, two Red
Bartlett varieties, Anjou, Bosc, Comice, Concorde, and Seckel.

9. Breeding objectives
 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
resistant.

10. Floral biology
1. Pear blossoms are white, rarely pinkish, and born in umbel like
Corymb.
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
base.
4. The ovary has 5 locules with 2 ovules per locule with a
maximum seed set obtain of ten.

12. Breeding system
 Incompatibility and sterility
 Polyploidy
 Mutation
 Hybridization and mating designs
 Parental selection, progeny testing, and progeny size

13. Mutation breeding
 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.

14. Biotechnology
 Cell and tissue culture
 Somaclonal variability and
genetic improvement
 Transformation

15. Breeding for specific tree and production
characters
1. Growth habit
2. Precocity
3. Self incompatibility
4. Parthenocarpy
5. Productivity

16. Fruit character
1. Fruit quality
2. Flavour
3. Texture
4. Skin colour
5. Russets
6. Flesh colour
7. Fruit size
8. Fruit shape
9. Ripening Season
10.Storage quality
11.Processing quality

17. Achievement and Prospects
Scion cultivars
 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.

18. 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
1980.
 The release of such partially resistance or tolerant cultivars such
as ‘Harrow Sweet’, ‘ ‘Harrow Crisp’, ‘Blake’s Pride’, ‘Aida’ and
‘Boheme’.