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Plant Science into Practice
Dr Tina Barsby
Genetics, Plant Breeding and Agriculture
Plant Science into Practice
Dr Tina Barsby
NIAB, Huntingdon Road, Cambridge, UK
Agriculture: the most important event in human history
Matthew 7:18-7:20 A good tree cannot bring forth ev il fruit, neither can a corrupt tree bring forth good fruit. Every tree tha t bringeth not forth good fruit is hewn down, and cast into the fire. Wherefor e by their fruits ye shall know them.
Meeting the Demands of a Growing Global Market
• World population continues to increase• Per capita food consumption continues to rise• Consumers continue to demand improved taste, convenience, and nutrition
GROWING WORLD POPULATION (B)
Source: FAO, WHO
RISING CEREAL DEMAND (MMT)
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1981 1999 2015 2030
500
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1981 1999 2015 2030
TRANSITION NATIONS DEVELOPED NATIONS DEVELOPING NATIONS
“To feed the eight billion people expected by 2025, the world will have to double food production…”CSIS - Seven Revolutions
Feeding future populations means doubling the produ ctivity and improving the nutritional quality of crops
Plant Science into Practice
Dr Tina Barsby
‘Better seeds …better crops ’• Food crisis after WW1 • NIAB established by charitable
donations for ‘the improvement of
crops with higher genetic quality’
• Barriers to plant breeding, and to access for growers to improved varieties, were recognised barriers to enhanced food production
Plant Science into Practice
Dr Tina Barsby
The First Farmers Leaflets1932 Farmers leaflet1931 Farmers leaflet
Plant Science into Practice
Dr Tina Barsby
•DuPont Food security index (there are others)•http://foodsecurity.eiu.com
AvailabilityAffordabilitySafety and Quality
Plant Science into Practice
Dr Tina Barsby
Plant Science into Practice
Dr Tina Barsby
Plant Science into Practice
Dr Tina Barsby
Agriculture in Tanzania
• Agriculture Sector Development Strategy 2001
strong donor (esp World Bank) support
• Kilimo Kwanza 2009: ten pillars support large
and small scale
• External interests in large scale agriculture
• Specialised areas: flowers, seeds
• Small scale is unpredictable poor performing
• Tanzania Development Vision Review 2025
requires a 6% p.a. growth in Agriculture
Agriculture in Tanzania
• Global challenges
• Local challenges of climate, soil,
infrastructure, prices, growth of cities, exports
• Large and small farms needed (outgrowers)
• Small farm improvement is needed to reduce
poverty
• Genetics and plant breeding transcends all of
this!
Norman E. Borlaug
Genetic Software & Hardware
Growth rates due to early years of the Green Revolution (1961-1980)
0
0.5
1
1.5
2
2.5
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Latin America Asia Middle East Africa
Other inputsCultivars
Growth rates due to late years of the Green Revolution (1981-2000)
-0.5
0
0.5
1
1.5
2
2.5
Latin America Asia Middle East Africa
Other inputsCultivars
Wheat
Genetic history: plant breeding.
Dwarfing genes allow increased:
•Nitrogen fertiliser levels.
Which increased susceptibility to disease. But plants were protected by newly developed:
•Fungicide
Dwarfing genes reduced the weight of straw, changing the distribution of resources and resulting in:
•Higher grain yields.
In addition, pleiotropic effects of the dwarfing gene include more grains per ear.
• What do plant breeders do? • How do they ‘introduce dwarfing genes’?• Where do these new genes come from?• Other questions?
Pedigree method
Performance under farmers’ conditions and farmers’acceptance
Participatory maize breeding in Africa
• Prioritize most important stresses under farmers’conditions
• Manage trials on experiment station and evaluate large numbers of cultivars,
• Select the best, and …
• Involve farmers– Mother trials in center of farming
community grown under best-bet input conditions
– Farmer-representative input conditions
– Farmer-managed baby trials
• Partnership with extension, NGOs, rural schools, and farmer associations
The Mother / Baby trial design
Collaborative, on-farm evaluation of maize cultivars
Holistic Research
“No matter how excellent the research done in one scientific discipline is, its application in isolation will have little positive effect on crop production. What is needed are venturesome scientists who can work across disciplines to produce appropriate technologies and who have the courage to make their case with political leaders to bring these advances to fruition. ”
Norman E. Borlaug
•Father of the Green revolution: Norman Borlaug.
•Where did he find the dwarf gene-Diversity! Japanese accession..Gene Banks importance
•How did he make possible to grow dwarf wheat in a variety of environments? Hybridisation, crossing
Fundamental role of Diversity & Selection
Reference: Michael Balter (2007) Seeking Agriculture’s Ancient Roots, Science 316, 1830-1835
Crop Biodiversity
The Seed Vault at SvalbardGlobal Crop Diversity Trust
Sources of novel variation
• International germplasm
• Landrace, or traditional varieties
• Wild relatives
• Progenitor species
Vavilov 1887-1943
•Soviet botanist & geneticist•Discovered and identified centres of origin of cultivated plants•Criticised the non-Mendelian concepts of Lysenko•Arrested in 1940, died of malnutrition in prison in 1943.
Many plant species have been domesticated around the world
All of the principal crops we rely on today come from domesticated species
The practice of artificial selection has been practiced by farmers for thousands of years and has transformed wild plants into the crops we depend on today through this process of domestication
Domestication: the first plant breeders
Domestication traits: traits that distinguish seed & fruit crops from their progenitors
Crop origins and diversification
Science 316, 1830-1835
ESEB Congress, Uppsala,
Sweden, August 2007
Little overlap between centres of origin & today’s
productive agriculture.
ESEB Congress, Uppsala,
Sweden, August 2007
Nature Vol 418, 700-707
Gene Banks
• Preserve Diversity• Collections, libraries• International, National and Local• Curation• Need maintenance, checking for viability..• Access• Link to other information
BIOLOGY is the science of the BIOLOGY is the science of the natural world & critical to the natural world & critical to the
future of agriculture.future of agriculture.
‘all life depends on sunlight and a green leaf’
Courtesy Tobert Rocheford and Catherine Bermudez Kandianis
Keith Weller
Doug Wilson
Scott Bauer
Keith Weller
• Organisation and Importance of Diversity• Linking biological knowledge to seed bank
collections• Selection is a powerful tool but need to
understand & know what to select for• The characteristics of plants are controlled
by genes.
DNA - the code for life
• The DNA code consists of just 4 building blocks:– A, C, T and G.
• Whether we are bacteria, fungi earthworms, mushrooms or humans our DNA has the same building blocks, just in a different order.
A C T G ...GCCTTACG…
....ACTGCCTGGAAC….….TGACGGACCTTG….
Source: Microsoft Encarta
Source: Microsoft Encarta
Maize has more molecular diversity than humans and apes combined
Silent Diversity (Zhao PNAS 2000; Tenallion et al, PNAS 2001)
1.34%
0.09%
1.42%
Genes (Every organism carries inside itself what are known as genes)
• DNA is divided into sections called genes.
• Each gene codes for a protein
• Each protein has a function
• DNA makes up the chromosomes
Chromosome changes: mutations
DNA isolation
• DNA• Chromosomes• Nucleus• Cells• Tissues• (Fruits)
Genes provide the foundation of new products for farmers
biomass utility?improved agronomy?tolerance to cold?
yield?tolerance to drought?flowering time?
Genes Protein Trait Product
Wheat a classic allo-hexaploid
ESEB Congress, Uppsala,
Sweden, August 2007
Science Vol 316, 1862-1866
Plant Breeding: Mining Diversity
• Genotypic and phenotypic assessment of 440 CIMMYT primary SHW
• Identified reduced group of 94 for back-crossing to Xi19 & Paragon by diversity analysis
• Develop UK adapted synthetic backcross derived lines (SHW-D) approx. 6,000 lines
• Assess agronomic characteristics of SHW-D including pest & disease resistance, yield components, drought tolerance and nitrogen use efficiency
SHW back-crossing by NIAB
SHW back-crossing by CIMMYT
Delayed senescence Increased grain sites
Paragon x SHW BC1F2 selections
Drought in Africa between now and 2090
Red, Orange =
More prone to drought
Blue =
Wetter and less prone to drought
Hadley Centre, Met Office, UK
Evaluation of drought toleranceHigh spike photosynthesis
Stem reserves
Large seed
Early ground cover
Leaf traits: wax, rolling, thickness, etc.
Long coleoptile
Water relations: stomatal conductance, etc.
Cellular traits: osmotic adjustment, heat tolerance, etc.High pre-anthesis biomass
Drought assessment at CIMMYT Mexico
Tractor-mounted Giddings soil corer
Drought trials at Obregon, N. Mexico
Conventional pedigree selection
Reproduced from Koebner & Summers 2003
Marker- Aided Selection
• Isolating DNA
• ‘Cutting’into pieces
• Amplifying
• Visualising
• Locating
Chromosome changes: mutations
• A new characteristic is the result of gene
mutation
• Genes can be amplified and ‘seen’ as
molecular markers.
• Breeders are choosing genes or
combinations of genes which give the
characters the farmer needs
• The crop is then multiplied and sold
Tissue Culture
• Margaret Karembu of ISAAA talking about TC
in bananas
Genetics
• The science underlying plant breeding.
Heredity
•Heredity is the passing of traitsto offspring (from its parent or ancestors).
Offspring resemble their parents more than they
resemble unrelated individuals (why is this so?)
Charles Darwin
Evolution is driven by natural selection
Darwin’s mentor
Great Teachers often feature in the development of Great People!
Gregor Johann Mendel, (b. 22 July 1822; d. 6 January 1884)Moravia, Austro-Hungarian Empire
Originator of the concept of the gene
(autosomal inheritance)Birthplace of Modern Genetic Analysis
Augustinian monastry garden, St. Thomas,
Brünn, Austria
Brno (Czech Rep.)
Experimemts, 1856-1870
Mendel’s Laws
• Law of equal segregation (First Law)- The two members of a gene pair
segregate from each other into the gametes; so that half the gametes carry one member of the pair and the other
half of the gametes carry the other member of the pair.
• Law of Independent Assortment (Second Law)
- different gene pairs assort independently during gamete formation
Reasons for choosing to study garden pea
•Can be grown in a small area
•Produce lots of offspring
•Easily identifiable traits
•Can be artificially cross-
pollinated
A pea flower with the keel cut and opened to expose the reproductive parts
Artificial cross pollination
Genes (The genes are codes or messages. They carry information. The information they carry is used to tell the organism what chemicals it needs to make in order
to survive, grow or reproduce )
• Genes make us who we are
• We receive our genes from our parents
• The same is true for all animals, plants and microbes
The seven character differences studied by Mendel
purple-flowered (f) x white flowered (m)
Summary and conclusions of Mendel’s experiments
•After crossing pure parental strains, the
F1 produced 100% of one character.
•After self-pollinating the F1, both
characters showed up in a 3:1 ratio.
•Because the same types of ratio kept
coming up, Mendel believed that there
must be some mathematical formula or
explanation for the observed data
•The first assumption made by Mendel
was that there must be a ”pair of
factors” that controls the trait in pea
plant. This “pair of factors” idea helped
him formulate his principles
Dominant and recessive traits
Mendel’s Laws
• Law of equal segregation (First Law)- The two members of a gene pair
segregate from each other into the gametes; so that half the gametes carry one member of the pair and the other half of the gametes carry the other
member of the pair.
• Law of Independent Assortment (Second Law)
- different gene pairs assort independently during gamete formation
Information from genes.
Plant Science into Practice
Dr Tina Barsby
•Agriculture depends on plant breeding, choosing the best, crossing the best with the best and hoping for the best…•With a little guidance from genetics!•Multiplication and propagation
Plant Science into Practice
Dr Tina Barsby
•Developing an industry-wide resource, showcasing new technology and innovation in plant genetic developmentfor the agriculture and horticulture sectors, on themes of:
Sexual reproduction in plants
F1 Hybrids
ESEB Congress, Uppsala,
Sweden, August 2007
Hybrid vrs Open pollinated maize
On the right a new, hybrid
maize variety developed by
CIMMYT with PASS funding.
On the left, a local landrace
variety
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USA: Historic Maize Yields
Yield(tonnes/ha)
6
5
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1
0
1875 1925 1975
0
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1929
1933
1937
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1945
1949
1953
1957
1961
1965
1969
1973
1977
1981
1985
1989
1993
1997
Year
Yie
ld (
kg/h
a)
United States
Inbred Varieties Hybrid Cultivars
History of Hybrids in Sorghum
Hybrid Seed Production– Getting the cross
• Hybrids are produced by hand emasculation
in corn.
• In wheat, chemicals are used to sterilize the
pollen.
• Cytoplasmic male sterility (CMS) is used for
hybrid seed production in sorghum and
pearl millet.
Training of Seed Growers in Hybrid Production
Crossing A and B lines Heat sterilization of pollen using polythene bag
Identifying the different parts of the sorghum plant
Hybrid Vigour is the superiority of progeny (offspring) (F1) over the mean of its two parents (P)
heterozygous
heterosis inbreeding depression
homozygous
selfing
Concepts of Hybrid Production - Hybrid Vigour (Heterosis)
• Making FI Hybrids
• And the F2…
Plant Science into Practice
Dr Tina Barsby
•Developing an industry-wide resource, showcasing new technology and innovation in plant genetic developmentfor the agriculture and horticulture sectors, on themes of: