Download Traditional and Modern Breeding Methods

SUSTAINABILITY, GENETICS, AND FUTURE CULTIVARS
Traditional and Modern Breeding
Methods
Ray Shillito, Bayer CropScience
May 23, 2014
Lima, Peru
Slide 1
Crop Improvement is Important
Wayne Parrott
University Georgia, USA
Change in Maize Productivity (USA)
Challenges for Agri-Businesses
Limited arable
land coupled
with rising
demand
Safeguard and increase yields from constant land area
better resource management (targeted use of crop
protection, irrigation technology and fertilizers)
increase yields through innovative technologies
(hybridization, plant biotechnology)
Expand agricultural production in marginal areas
new crops with greater tolerance of drought and extreme
temperatures
Climate change
Increase tolerance of plants to climatic variability
develop new varieties using state-of-the-art technologies
improve plant health and nutrient uptake
Research and innovation are the key to mastering the challenges of
the New Ag Economy
Slide 4
Key goals for plant breeders
• Insect protection
• Salinity tolerance
• Multiple herbicide
• Cold and frost tolerance
tolerance
• Drought tolerance
• Disease resistance
• Hybrid production
• Nutrient use efficiency
• Carbon sequestration
• Oil, starch and amino acids
• Nutrient quality
Achieving all these goals will require not only traditional breeder skills, but will
be accelerated by the use of novel molecular techniques and biotechnology
Traditional Plant Breeding
• Since the beginning of civilization
• Desirable traits —bigger fruit, leafier greens,
or disease resistance
• Natural or induced mutations and selective
breeding.
• Hopefully the trait is passed on to the next
generation.
• Long, hit and miss process that can take many
generations
• Many genes may contribute to a trait
Corbis
Corbis
Corbis
Breeding of new varieties
Crossing or
mutation
Successive generations
of selection
Commercial varieties
Plant with the desired
characteristics (genes)
Thousands
Hundreds
10s
1
How Does Modern Plant Breeding
Differ
•
•
•
•
•
•
•
•
Speeding up selective breeding via markers
Genetic rather than Phenotypic
Identify genes that contribute to a trait
Efficiency through molecular tools and
robotics
Targeted process that takes less generations
Addition of Specific genes
Specific changes to Specific genes
Understanding the structure of the genome
Sources of
Crop genetic
variation
Mutagenesis
Irradiation
Transgenesis
Standing
variation
Chemical
Nucleotide
polymorph
Single
/multiple
gene(s)
Gene
content
polymorph
Transp.
Genic
Transp.
PAV
Qualitative
trait
SNP/Indels
Nongenic
Del/Dup
Reverse
screens
Forward
screens
CNV
Bob Stupar
University of Minnesota, USA
Select?
Stressresponse?
Predict?
Types of genetic variation
Bob Stupar
University of Minnesota, USA
• DNA sequence differences (SNPs/Indels)
• DNA transpositions
• DNA structural changes
– Large (>1 kb) deletions, duplications,
inversions, translocations
Mutation breeding
2543 known varieties
developed from mutation
breeding
FAO/IAEA database
(http://www-
infocris.iaea.org/MVD/)
DNA changes
– 4 bp to 8 kb deletions
– Inversions of up to 1.5 kb
– Insertions ~200 bp
– Frame-shift mutations
– Premature stop codons
Institute of Radiation Breeding
Ibaraki-ken, JAPAN
www.irb.affrc.go.jp/
DNA: Target of Modern Breeding
DNA can be considered like a strand of
pearls: each gene is made up of many
base-pairs (ATCG)
Each pearl represents a gene that
encodes a protein, or a characteristic
of the plant (a phenotype).
DNA is a strand of genes, much like a strand of pearls.
Traditional plant breeding combines many genes at once; the
undesirable ones have to be bred out.
X
X
X
X
X
X
X
X
X
Mutation breeding changes produces mutations in many
genes; the undesirable ones have to be bred out.
Modern Plant Breeding
• Marker assisted breeding is very similar to
traditional selective breeding; it uses genetic
markers to identify which plants contain the
best gene combinations.
• Genetic markers may identify the exact genes
responsible for a particular trait.
• Breeders can locate identify progeny that
that have the specific genes.
• This can speed up breeding for a desired
trait.
http://www.plantgenomesecrets.org/ Iowa State U./NSF
Traditional plant breeding combines many genes at once; the
undesirable ones have to be bred out.
X
X
X
X
X
X
X
X
Modern tools
can speed up
this process by
identifying
those plants
that have the
most desirable
combination of
genes
Modern Breeding of New Varieties
Crossing or
mutation
Successive generations
of selection
Commercial varieties
Plant with the desired
characteristics (genes)
Thousands
Hundreds
10s
1
Traditional plant breeding combines many genes at once; the
undesirable ones have to be bred out.
X
X
X
X
Modern Biotechnology
can insert specific
genes, without adding
undesirable genes,
or directly change a
target gene
X
The Modern Toolbox:
Tool
Benefits
DNA trait markers
Can eliminate need for phenotyping of plants
Individual seed
/plant testing
Saves time/money/space/labor, increases breeding
throughput
Robotics
Speed increase by integration of workflows in analysis of
markers
Expression on
introduced genes
Biotech approach to add new genes (herbicide and
insect tolerance)
“RNAi”
Biotech approach to alter biochemical pathways through
the alteration of native gene expression
TALENs/CRISPRs
Emerging techniques for the specific editing of native
genes.
Genome wide
selection/
genotyping by
sequence
Emerging technique enabled by cheap/fast DNA
sequencing for the discovery of new markers for
breeding, acceleration of backcrossing
How might modern breeding
technologies impact the supply chain?
• Increase the availability of
grain/food
• Allow food production under
changing climate conditions
• Change the composition in directed
ways
• Require improved identity
preservation