The document discusses gene pyramiding, a plant breeding technique aimed at combining multiple genes from different parents to enhance pest resistance and crop yield. It highlights methods such as iterative hybridization, re-transformation, and co-transformation, along with examples of commercially successful genetically modified crops. The conclusion underscores the significance of gene pyramiding in improving germplasm and the role of molecular markers in streamlining the breeding process.

1. ANAND AGRICLTURAL UNIVERSITY
B. A. COLLEGE OF AGRICULTURE
Topic: Gene Pyramiding
GP-501 :- Principles Of Plant breeding (2+1)
Course Teacher: Dr. J. N. Patel
Prepared By,
Dhanya A J,
[ Reg. No: 04-2348-2014 ],
M. Sc. (Agri) Plant Molecular -
Biology & Biotechnology

2. Introduction
 The development of molecular genetics and
associated technology like MAS has led to the
emergence of a new field in plant breeding-Gene
pyramiding.
 The term gene pyramiding is used in agricultural
research to describe a breeding approach to achieve
pest control and higher crop yield.
 Gene pyramiding aims at the derivation of an ideal
genotype that is homozygous for the favorable alleles
at all n-loci. Molecular markers aid in selecting the
best plants with which to proceed.

3. Gene Pyramiding
MAS based gene pyramiding could facilitate in
pyramiding of genes effectively into a single genetic
background.
Gene pyramiding or stacking can be defined as
a process of combining two or more genes
from multiple parents to develop elite lines and
varieties.
or
Pyramiding entails stacking multiple genes leading to
the simultaneous expression of more than one gene in
a variety.

4. Strategies For Gene Stacking /
Pyramiding
Iterative Procedure / Sexual
Hybridization
Re- Transformation
Co- Transformation

5. Iterative Procedure / Sexual
Hybridization
A plant harboring one or more transgenes
is cross-hybridized with another plant
containing other transgenes. Development
of a multi-stack hybrid occurs via iterative
hybridization.
 Examples of commercial stacks
Maize: Agrisure™ Viptera™ 3220 (Bt11 x MIR162 x
TC1507 x GA21)
Cotton: Roundup Ready™ Flex Bollgard™ II
(MON88913 x MON15985)

6. Methods

7. The gene pyramiding scheme can be
distinguished into two parts (Figure 1).
The first part is called a pedigree, which
aims at cumulating of all target genes in a
single genotype called the root genotype.
The second part is called the fixation step
which aims at fixing the target genes into a
homozygous state i.e. to derive the ideal
genotype from the one single genotype

9. Re- Transformation
Examples of commercial stacks
Cotton: Bollgard™ II
A plant harboring a transgene is
transformed with other transgenes.

10. Re-transformation.
A plant harbouring transgene A is retransformed with transgene B

11. Co- Transformation
A plant is transformed with two or more
independent transgenes. The transgenes
of interest are in separate gene constructs
and delivered to the plant simultaneously.
 Examples of commercial stacks
Maize: NaturGard™ Knockout™ (Bt176), BtXtra™
(DBT418), YieldGard™ (MON810,
MON809, MON802), Herculex™ I
(TC1507), Herculex™ RW (59122),
Agrisure™ CB/LL (Bt11)
Soybean: Vistive™ Gold

12. Single-plasmid Co-transformation.
Transgenes A and B are linked on one piece of DNA and
transferred together into a plant.

13. Multiple-plasmid co-transformation.
Transgenes A and B are on different pieces of DNA that are
transformed together into a plant

15. Conclusion
 Gene pyramiding is an important strategy
for germplasm improvement.
 Molecular marker genotyping can
facilitate the gene pyramiding process by
reducing the number of generations that
breeders must evaluate to ensure they
have the desired gene combination.

16. Reference
 http://www.isaaa.org/resources/publications/pocketk/42/
 Gene Pyramiding Using Molecular Markers- Francis et
al., 2012
 http://agbiosafety.unl.edu/education/backcross.htm
 Gene pyramiding-A broad spectrum technique for
developing durable stress resistance in crops.- Joshi et al.,
2010