Presentation at the November 2012 dialogue workshop of the Biosciences for Farming in Africa media fellowship programme in Arusha, Tanzania. Please see www.b4fa.org for more information

1. Dr Tina Barsby
Plant Science into Practice
Genetics, Plant Breeding and
Agriculture

2. Dr Tina Barsby
Plant Science into Practice
NIAB, Huntingdon Road, Cambridge, UK

3. Agriculture: the most important
event in human history

4. Matthew 7:18-7:20 A good tree cannot bring forth evil fruit, neither can a
corrupt tree bring forth good fruit. Every tree that bringeth not forth good
fruit is hewn down, and cast into the fire. Wherefore by their fruits ye
shall know them.

5. Meeting the Demands of a Growing Global Market
GROWING WORLD POPULATION (B)
9
RISING CEREAL DEMAND (MMT)
3000
8
2500
7
6
2000
5
1500
4
3
1000
2
500
1
1981
1999
2015
TRANSITION NATIONS
•
•
•
2030
1981
DEVELOPED NATIONS
1999
2015
2030
DEVELOPING NATIONS
World population continues to increase
Per capita food consumption continues to rise
Consumers continue to demand improved taste, convenience, and nutrition
“To feed the eight billion people expected by 2025, the world will have to double food production…”
CSIS - Seven Revolutions
Source: FAO, WHO

6. Feeding future populations means doubling the productivity and improving the
nutritional quality of crops

7. Dr Tina Barsby
Plant Science into Practice
‘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

8. Dr Tina Barsby
Plant Science into Practice
1931 Farmers leaflet
1932 Farmers leaflet
The First Farmers Leaflets

9. Dr Tina Barsby
Plant Science into Practice
•DuPont Food security index (there
are others)
•http://foodsecurity.eiu.com
Availability
Affordability
Safety and Quality

10. Dr Tina Barsby
Plant Science into Practice

11. Dr Tina Barsby
Plant Science into Practice

12. Dr Tina Barsby
Plant Science into Practice

13. 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

14. 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!

15. Norman E. Borlaug

16. Genetic Software & Hardware

17. Growth rates due to early years of the
Green Revolution (1961-1980)
3.5
3
2.5
2
Other inputs
Cultivars
1.5
1
0.5
0
Latin America
Asia
Middle East
Africa

18. Growth rates due to late years of the
Green Revolution (1981-2000)
2.5
2
1.5
Other inputs
Cultivars
1
0.5
0
-0.5
Latin America
Asia
Middle East
Africa

20. Wheat
Genetic history: plant breeding.
Dwarfing genes
reduced the
weight of straw,
changing the
distribution of
resources and
Dwarfing genes
resulting in:
allow increased:
•Higher grain
•Nitrogen fertiliser
yields.
levels.
In addition,
Which increased
pleiotropic effects
susceptibility to
of the dwarfing
disease. But plants
gene include
were protected by
more developed:
newly grains per
ear.
•Fungicide

21. •
•
•
•
What do plant breeders do?
How do they ‘introduce dwarfing genes’?
Where do these new genes come from?
Other questions?

22. Pedigree method

23. 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
Performance under
farmers’ conditions
and farmers’
acceptance

24. 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

25. •Father of the Green revolution:
Norman Borlaug.
•Where did he find the dwarf geneDiversity! Japanese
accession..Gene Banks importance
•How did he make possible to grow
dwarf wheat in a variety of
environments? Hybridisation,
crossing

26. Fundamental role of Diversity &
Selection
Reference: Michael Balter (2007) Seeking Agriculture’s Ancient Roots, Science 316, 1830-1835

27. Crop Biodiversity
The Seed Vault at Svalbard
Global Crop Diversity Trust

28. Sources of novel variation
•
•
•
•
International germplasm
Landrace, or traditional varieties
Wild relatives
Progenitor species

33. Vavilov 1887-1943
•Soviet botanist & geneticist
•Discovered and identified
centres of origin of cultivated
plants
•Criticised the nonMendelian concepts of
Lysenko
•Arrested in 1940, died of
malnutrition in prison in
1943.

34. Many plant species have
been domesticated
around the world
All of the principal crops we
rely on today come from
domesticated species

35. Domestication: the first plant
breeders
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

36. Domestication
traits: traits that
distinguish seed &
fruit crops from
their progenitors

37. Crop origins and diversification
Science 316, 1830-1835
ESEB Congress, Uppsala,
Sweden, August 2007

38. Little overlap between centres of origin & today’s
productive agriculture.
Nature Vol 418, 700-707
ESEB Congress, Uppsala,
Sweden, August 2007

39. Gene Banks
•
•
•
•
•
•
•
Preserve Diversity
Collections, libraries
International, National and Local
Curation
Need maintenance, checking for viability..
Access
Link to other information

40. ‘all life depends on sunlight
and a green leaf’
BIOLOGY is the science of the
natural world & critical to the
future of agriculture.

41. Courtesy Tobert Rocheford and
Catherine Bermudez Kandianis
Keith Weller
Keith Weller
Scott Bauer
Doug Wilson

42. • 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.

43. DNA - the code for life
• The DNA code consists
of just 4 building
blocks:
– A, C, T and G.
A C T G
...GCCTTACG…
....ACTGCCTGGAAC….
….TGACGGACCTTG….
Source: Microsoft Encarta
• Whether we are
bacteria, fungi
earthworms, mushrooms
or humans our DNA has
the same building
blocks, just in a
different order.
Source: M
icrosoft Encarta

44. Maize has more molecular diversity
than humans and apes combined
1.34%
0.09%
1.42%
Silent Diversity (Zhao PNAS 2000; Tenallion et al, PNAS 2001)

45. 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

46. Chromosome changes: mutations

47. DNA isolation
•
•
•
•
•
•
DNA
Chromosomes
Nucleus
Cells
Tissues
(Fruits)

48. Genes provide the foundation of new products for
farmers
Genes
Protein
yield?
tolerance to drought?
flowering time?
Trait
biomass utility?
improved agronomy?
tolerance to cold?
Product

49. Wheat a classic allo-hexaploid
Science Vol 316, 1862-1866
ESEB Congress, Uppsala,
Sweden, August 2007

51. Plant Breeding: Mining
Diversity
•
•
SHW back-crossing by CIMMYT
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
•
SHW back-crossing by NIAB
Genotypic and phenotypic
assessment of 440 CIMMYT
primary SHW
Assess agronomic
characteristics of SHW-D
including pest & disease
resistance, yield components,
drought tolerance and
nitrogen use efficiency

52. Paragon x SHW BC1F2 selections
Delayed senescence
Increased grain sites

53. 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

54. Evaluation of drought
tolerance
High spike photosynthesis
Stem reserves
High preanthesis biomass
Cellular traits: osmotic adjustment, heat tolerance, etc.
Leaf traits: wax, rolling,
thickness, etc.
Early ground cover
Long coleoptile
Large seed
Water relations:
stomatal conductance,
etc.

55. Drought assessment at
CIMMYT Mexico
Drought trials at Obregon, N. Mexico
Tractor-mounted Giddings soil corer

56. Conventional pedigree selection
Reproduced from Koebner & Summers 2003

57. Marker- Aided Selection
• Isolating
DNA
• ‘Cutting’
into pieces
• Amplifying
• Visualising
• Locating

58. Chromosome changes: mutations

59. • 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

61. Tissue Culture
• Margaret Karembu of ISAAA talking about TC
in bananas

63. Genetics
• The science underlying plant breeding.

64. Heredity
•Heredity is the
passing of traits
to offspring
(from its parent
or ancestors).
Offspring resemble their parents more than they
resemble unrelated individuals (why is this so?)

65. Charles Darwin
Evolution is driven by natural selection

66. Darwin’s mentor
Great Teachers often feature in the development of Great People!

67. Gregor Johann Mendel,
(b. 22 July 1822; d. 6 January 1884)
Moravia, Austro-Hungarian Empire
Brno (Czech Rep.)
Experimemts, 1856-1870
Originator of the concept of the gene
(autosomal inheritance)
Birthplace of Modern Genetic Analysis
Augustinian monastry garden, St. Thomas,
Brünn, Austria

68. 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

69. Reasons for choosing to study garden pea
•Can be grown in a small area
•Produce lots of offspring
•Easily identifiable traits
•Can be artificially crosspollinated

70. A pea flower with the keel cut and opened
to expose the reproductive parts

71. Artificial cross pollination

72. 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

73. The seven character differences studied by Mendel

74. purple-flowered (f) x white flowered (m)

75. 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

76. Dominant and recessive traits

78. 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

79. Information from genes.

80. Dr Tina Barsby
Plant Science into Practice
•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

81. Dr Tina Barsby
Plant Science into Practice
•Developing an industry-wide resource, showcasing new
technology and innovation in plant genetic development
for the agriculture and horticulture sectors, on themes of:

82. Sexual reproduction in plants

83. F1 Hybrids
ESEB Congress, Uppsala,
Sweden, August 2007

84. Hybrid vrs Open pollinated maize
On the left, a
local landrace
variety
On the right a
new, hybrid
maize variety
developed by
CIMMYT
with PASS
funding.

85. USA: Historic Maize Yields
6
5
Yield
(tonnes/ha)
4
3
2
1
0
1875
1925
To put your footer here go to View > Header and Footer
1975
85

86. History of Hybrids in Sorghum
5000
United States
4500
3500
3000
2500
2000
Inbred Varieties
1500
Hybrid Cultivars
1000
500
Year
1997
1993
1989
1985
1981
1977
1973
1969
1965
1961
1957
1953
1949
1945
1941
1937
1933
0
1929
Yield (kg/ha)
4000

87. 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.

88. 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

89. Concepts of Hybrid Production - Hybrid Vigour (Heterosis)
Hybrid Vigour is the superiority of progeny (offspring) (F1)
over the mean of its two parents (P)
heterozygous
heterosis
inbreeding depression
homozygous
selfing

90. • Making FI Hybrids
• And the F2…

91. Dr Tina Barsby
Plant Science into Practice
•Developing an industry-wide resource, showcasing new
technology and innovation in plant genetic development
for the agriculture and horticulture sectors, on themes of: