Assignmenton

Clonal selection and it’s utilization in fruit breeding

Presented by

Mr Manas Kumar

Patel

(01Fsc/2014)

Clone

Progeny of a single plant obtained by asexual reproduction is known as clone.

Crop which are propagated asexually or by vegetative means clonal crops.

Clones developed by asexually

Features of Clones Homogeneous constitution :- Plants of a clone have similar genetic constitution.

Heterozygosity :- Phenotypically similar but heterozygous.

Lack of genetic variation :- Phenotypically variation present within a clone is due to environmental effect not genetically.

P=G+E+GE+mu

Immortality :- Maintained by asexual reproduction

Vigorous growth :- Clonal selection is useful in conserving the heterosis far a long period of time.

Wider Adaptation :- Due to high level of heterozygosity than pure lines.

Origin of Genetic variation within Clones.

1. Somatic mutation

2. Mechanical mixture

3. Sexual reproduction

4. Segregation in F1

Compairision among Clones, Purelines and Inbreds

Particulars Clone Pureline Inbred

Mode of pollination Cross pollination Self pollination Cross Pollination

Natural mode of reproduction Asexual Sexual Sexual

Genetic makeup of plant population Heterozygous Homozygous Hetrozygous

Obtain through Asexual reproduction from a single plant

Natural S.P. from a single homozygous plant

Artificial self pollination and selection for several generation

Maintained through Asexual reproduction Natural self pollination

Artificial self pollination or Close Inbreeding

Used as a variety Yes Yes No (Used for Hybrid and synthetic Hybrid development)

Genetic makeup of plant with in an entity

Heterozygous Homozygous Almost Homozygous

Clonal DegenerationThe loss in vigour and productivity of clone with time is known as clonal degeneration. Clonal degeneration= Degeneration is inherent in the clone. Degeneration may result from

1) Mutation

2) Viral diseases

3) Bacterial diseases

Method of improvement

A single outstanding plant select from a population forms the basis of a new variety.

The breeding behaviour of genotype of this plant is not important since there would be no further sexual reproduction.

An improved variety that has becomes variable, or from a population produces by crossing two or more clones.

Clonal selections

Improvement of asexually propagated crops by selecting superior clones is known as clonal selection.

Superior clones can be isolated from three types of materials1) Local variety2) Introduced variety3) Inter crossed population

Step for

clonal

selection

Breeding procedure of clonal selection

FIRST YEAR :-

a) From a mixed variable population, few hundred to few thousand desirable plant are selected.

b) A rigid selection can be done for simply inherited characters with high heritability.

c) Plant with obvious weakness are eliminated.

SECOND YEAR:-

Clones from the selected plants grown separately.

a) Desirable clones selected

THIRD YEAR :-Preliminary yield trials with standard checks.

a) Selection for quality, disease resistance etc. Disease nurseries may be planted.

b) Few outstanding clone selected.

FOURTH-SIXTH YEAR :-

Multilocation yield trials with standard checks.

a) Best clone identified for release as a new variety.

SEVENTH YEAR :-

The best clone release as a new variety.

a) Seed multiplication for distribution begins.

Schematic representation

of clonal selection

Merits1) Useful in conserving heterosis for several generations

i.e. method retains all the characteristic of the parental clone for several years.

2) Highly uniform and stable

3) Effective method for genetic improvement of asexually propagated crop plants.

Demerits:-1) Highly prone to new disease of new Races.

2) Can’t create new variability.

Papaya:-

Pineapple:-

Litchi:-

Aonla:-

Bael:-

Pomegranate:-

– CO-1, CO-2, CO-5, CO-6, Pusa giant, Pusa dwarf.

– Singapore Spanish, MasmerahPuerto Rico

– glorff,Saharanpur sel, swarna roopa.

– NA-4, NA-5, NA-6, NA-7,NA-8,NA-10

– NB-1,NB-5, NB-6

– G-137,CO-1, YCD-1

crop Clonal variety

Achievements in fruit crops:-crop

Mango:-.

Grapes:-

Guava:-

Sapota:-

Clonal var– Dasehari-51, Niranjan, Cardoz mankurad, Payur-1

– Pusa seedless, Thomson seedless, Perlet, Tas –e- ganesh, Sonaka, Rao sahebi, dilkhus.

– L-49 Jyoti, Alandi, S-1, Arka mridula,

– Cricket ball, Kirthi bharti, Badami, Baramasi, Guthi, Thagarampudi.