1. BIOTECHNOLOGY FOR CROP IMPROVEMENT
GP 509
SUBMITTED TO:
Dr.D.SHIVANI
PROFESSOR
DEPT. OF GENETICS AND PLANT BREEDING
SUBMITTED BY:
K.BHARGAVA REDDY
RAM/18-56
MSC(AG)1ST YEAR
2. Marker assisted selection
CONTENTS:
What is MAS??
Marker and types
Prerequisites for marker assisted breeding
Features of MAS
General Steps in MAS
Applications
Merits and demerits
3. WHAT IS M.A.S.?
“Marker assisted selection or Marker aided selection (MAS) is
an indirect selection process where a trait of interest is selected
based on a marker (morphological, biochemical or DNA/RNA
variation) linked to a trait of interest (e.g. productivity, disease
resistance, abiotic stress tolerance, and quality), rather than on
the trait itself.”
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5. TYPES OF MARKERS
Morphological Markers:- these are related to size, shape, color
and surface of various plant parts
Cytological Markers:- such markers are related to variations in
chromosomes morphology
Biochemical Markers:- such markers are related to variations in
protein and amino acid banding patterns.
DNA markers:- they are related to variation in DNA fragments
generated by restriction end nuclease enzyme
6.
7. DNA MARKERS IN CROP
IMPROVEMENT
Germplasm characterization
Varietal identification
Tracing genetic origin of crop plants
Gene tagging
Genome mapping
MAS
8. MOLECULAR BREEDING
Conventional plant breeding is primarily based on
phenotypic selection of superior individuals among segregating
progenies resulting from hybridization.
studies have been made in crop improvement through
phenotypic selections for agronomically important traits,
considerable difficulties are often encountered during this
process, primarily due to G×E interactions.
MOLECULAR BREEDING helps to encounter this problems.
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13. FEATURES OF M.A.S.
Application
High accuracy
Rapid method
Environmental effect
Permits QTL tagging
Laboratory
Cost
Material developed
Speed of progress
17. DEVELOPMENT OF BREEDING
POPULATION
The selected parents are crossed
to obtain F1
50-100 F2 Plants are sufficient
for the study of segregation of
RFLP markers.
23. FACTOR FOR SUCCESS OF MAS
Availability of genetic map with an adequate number of
uniformly-spaced polymorphic markers to accurately locate
desired QTLs or major gene(s).
Close linkage between the QTL or a major gene of interest and
adjacent markers.
Ideally markers should be <5 cM from a gene or QTL
Using a pair of flanking markers can greatly improve reliability
but increases time and cost.
Adequate recombination between the markers and rest of the
genome.
Ability to analyze a larger number of Animals in a time and cost
effective manner.
24. MAS can enhance conventional breeding in
Early selection of traits
Independent to season and location for the trait
Gene pyramiding
Recovery of recurrent parent
Selection of parental lines with wider genetic base
Monitoring seed purity and germplasm identity
It is being used for transfer of male sterility into cultivated
genotypes from different sources.
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29. APPLICATIONS:
• Rapid method of transferring resistance to biotic and abiotic stresses
in crop plants
• Useful in gene pyramiding
• Transfer of male sterility and photoperiod insensitivity
• Improvement of quality characters (Eg. Protein quality in maize)
• Successfully used for transferring desirable transgene from one
cultivar to another (Eg. Bt gene)
• Effective in introgression of desirable genes from wild into
cultivated genotypes
• Effective in genetic improvement of plant and animals
• Genetic improvement of tree species (20 years)
• Wide application for genetic improvement of oligogenic traits as
compared to polygenic traits
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31. LIMITATIONS
Costly method
Well trained man power requirement
Detection of various linked marker are difficult to detect
,laborious ang time consuming task
Involves use of radioactive isotopes
Less efficient than phenotypic selection in long term
More difficult for QTL