1.3 plants and agriculture tina barsby

Plant Science into Practice

Dr Tina Barsby

Genetics, Plant Breeding and Agriculture


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

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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


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


Dr Tina Barsby

The First Farmers Leaflets1932 Farmers leaflet1931 Farmers leaflet


Dr Tina Barsby

•DuPont Food security index (there are others)•http://foodsecurity.eiu.com

AvailabilityAffordabilitySafety and Quality


Dr Tina Barsby


Dr Tina Barsby


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)

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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

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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.


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


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.


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


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


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

To put your footer here go to View > Header and Footer 85

USA: Historic Maize Yields

Yield(tonnes/ha)

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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…


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:

Technology

1.3 plants and agriculture tina barsby