Post on 15-Apr-2017
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.