Clonal selection and it’s utilization in
Progeny of a single plant
obtained by asexual
reproduction is known as
Crop which are propagated
asexually or by vegetative
means clonal crops.
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.
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
1. Somatic mutation
2. Mechanical mixture
3. Sexual reproduction
4. Segregation in F1
Compairision among Clones, Purelines and
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
Artificial self pollination and
selection for several generation
Maintained through Asexual reproduction Natural self
Artificial self pollination or Close
Used as a variety Yes Yes No (Used for Hybrid and synthetic
Genetic makeup of plant with in an
Heterozygous Homozygous Almost Homozygous
The loss in vigour and productivity of clone with time is known as
Clonal degeneration= Degeneration is inherent in the clone.
Degeneration may result from
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.
Improvement of asexually propagated crops by
selecting superior clones is known as clonal selection.
Superior clones can be isolated from three types of materials
1) Local variety
2) Introduced variety
3) Inter crossed population
Breeding procedure of clonal
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.
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
SEVENTH YEAR :-
The best clone release as a new variety.
a) Seed multiplication for distribution begins.
1) 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.
1) Highly prone to new disease of new Races.
2) Can’t create new variability.