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Pear

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Pear

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Pear

  1. 1. 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
  2. 2. pear Botanical Name :- Pyrus communis L Family:- Rosaceae Origin:- Europe Chromosome No.:- 2n = 51(Triploid)
  3. 3. 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
  4. 4. Ploidy levels in Pear 1.Triploid (2n = 51) 2. Tetraploids (2n = 68) 3. Hexaploid (2n = 102)
  5. 5. 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).
  6. 6. Different cultivar of Pear Blake's Pride pear Packham's Triumph pear Clairgeau pear Louise Bonne of Jersey pear
  7. 7. Varieties of Pear  Eight varieties of pears, from left to right, Bartlett, two Red Bartlett varieties, Anjou, Bosc, Comice, Concorde, and Seckel.
  8. 8. 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.
  9. 9. 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.
  10. 10. Breeding system  Incompatibility and sterility  Polyploidy  Mutation  Hybridization and mating designs  Parental selection, progeny testing, and progeny size
  11. 11. 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.
  12. 12. Biotechnology  Cell and tissue culture  Somaclonal variability and genetic improvement  Transformation
  13. 13. Breeding for specific tree and production characters 1. Growth habit 2. Precocity 3. Self incompatibility 4. Parthenocarpy 5. Productivity
  14. 14. 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
  15. 15. 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.
  16. 16. 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’.

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