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F1 Hybrids Claudia Canales

B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

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Page 1: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

F1 Hybrids

Claudia Canales

Page 2: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

The need for more food

• F1 hybrids • Fertilisers • Mechanisation (tractors)

U.S. maize yields in the last 100 years U.S. population growth in the last 100 years

8-fold increase in maize yield thanks to:

Page 3: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

What is a maize F1 hybrid?

The first generation (F1) of a cross between from two uniform parent inbred lines

F1 Hybrid

Parent 1 Parent 2

X CROSS

Page 4: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

Maize reproduction

Page 5: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

Each kernel is a genetically unique individual

Page 6: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

How do you make an F1 hybrid?

Page 7: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

3 steps

1: Development of parental inbred lines

By self-pollinations until a good degree of uniformity is achieved. Selection for type and good parent potential is done as the lines are inbred.

Inbreeding depression

Page 8: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

2: Test crossing: sets of two inbred lines are crossed (uniformly, with no selfing allowed)

How do you make an F1 hybrid? Cont.

Hybrid vigour

Page 9: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

3: Production crossing: commercial production of F1 hybrid seed. Expensive and labour-intensive.

How do you make an F1 hybrid? Cont.

Page 10: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

What are the advantages of F1 hybrids?

• It is uniform in appearance and behaviour: – enables farmer to treat and harvest crop at the same

time uniformity – has marketing advantages when sold to buyers with

strict quality standards)

• It has hybrid vigour (makes them more competitive with weeds)

• It is high yielding • It is selected for improved grain quality • A particular hybrid can be selected for specific

pest and disease resistance or drought tolerance

Page 11: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

Maize F1 hybrids

P1 P2 C B

14 days P1 P2 C B

Maize

Parent 1 Parent 2 Parent 2 Parent 1 F1 Hybrids F1 Hybrids

Page 12: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

Game introduction

• F2 generation of hybrid seed – variability and consequences

Page 13: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

• Hybrid seed is more expensive than open-pollinated maize seed

• Farmers situated in a low potential environment and who cannot afford extra inputs such as fertilizer may not recover the costs of the hybrid seed

• Fresh hybrid seed needs to be bought every planting season (farmers cannot replant grain as seed without major reductions in yield, which might be a decrease of 30 % or more)

What are the disadvantages of F1 hybrids?

Page 14: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

What are the disadvantages of F1 hybrids? Cont.

Parent 2

Parent 1

F1 Hybrid

F1 Hybrid seed selfed over several generations

Inbreeding depression

Hybrid vigour

Page 15: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

F1 hybrid seeds vs landraces

• Genetic uniformity can be a problem if the conditions are bad (such as extreme weather conditions, new pest or disease)

• Traditional landraces are genetically very variable, and hence more resilient, although yields are lower

• Landraces are invaluable sources of genetic diversity

Page 16: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

Consequences of hybridisation

• Bought seed vs seed saving

• (Lack of) Ability of individuals or government research institutions to produce in desired quantity and quality

• F1 hybrid production closely linked to the creation of private seed companies for commercial seed production (public versus private investment in plant breeding)

Page 17: B4FA 2013 Ghana: F1 hybrid seeds and plants - Claudia Canales

F1 hybrid seeds are not GM!! Why? Because they are produced by crossing two non-GM plants.

F1 Hybrid

Parent 1 Parent 2

X CROSS