This document discusses marker assisted selection (MAS) for crop improvement. It defines MAS as using markers linked to traits of interest, like productivity or stress tolerance, to indirectly select for those traits. It describes different types of markers, including morphological, cytological, biochemical and DNA markers. It outlines the general steps in MAS, including selecting parents, developing breeding populations, isolating DNA, scoring markers, and examples of MAS applications. Key benefits of MAS include early selection, independence from environment, and gene pyramiding, while limitations include cost and requirement of well-trained personnel.

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.”

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

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.

13. FEATURES OF M.A.S.
 Application
 High accuracy
 Rapid method
 Environmental effect
 Permits QTL tagging
 Laboratory
 Cost
 Material developed
 Speed of progress

15. General Steps in MAS

16. SELECTION OF PARENTS
Contrasting characters (or) Divergent origin
Homozygous
Self pollinated (homozygous)
Cross pollinated (inbreed lines)

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.

18. ISOLATION OF DNA

19. SCORING RFLPs

20. OVERVIEW OF MARKER GENOTYPING

21. EXAMPLES OF M.A.S.

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.

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

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