Plants and Agriculture – a history

Bernie Jones

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What do you know about farming?

1. I am a farmer

2. I grew up and/or have lived in a farming community

3. I am a city person, but members of my family farm

4. I have no experience of farming

5. What’s a farm?

5%

5%

9%

27%

55%

When did people start to farm?

1. People have always farmed

2. Around 10,000 years ago

3. Around 5,000 years ago

4. Around 2,000 years ago

5. Around 500 years ago

How did it start?

Early Farming

Domestication

When? Why? How?

9000BC Wheat/barley, Fertile Crescent

8000BC Potatoes, South America

7500BC Goats/sheep, Middle East

7000BC Rye, Europe

6000BC Chickens, South Asia

3500BC Horse, West Asia

3000BC Cotton, South America

2700BC Corn, North America

Diversity & Traits

Living things are variable

(This is genetics!)

Selection

Selection

• Early farmers discovered they could select better traits in their crops

• This becomes a continuous process

Crops already “genetically engineered” over 1000’s of years…

Selection

Change: mutation & crossing

• Natural mutations and crosses

• Selection for desirable traits

• Deliberate crossing/hybridisation

Deliberate plant breeding

• Realisation that attributes of plants could be deliberately influenced

• Launched plant breeding as necessity (disease) and “pastime”

• Gradual realisation that there must be principles underlying this process

• Constant searches to find new plant material for cross-breeding

Breakthrough of “genetics”

• Could observe some underlying principles…

• Led to gradual understanding and discovery of genetics and inheritance. More of this in next session

• But allowed breeding, and breeding process, to become much more focussed and productive

Where are we today

• All our crops are “modified” in some way

• Plant breeding and selection have been basic way of life for farmers for millennia

• Techniques have developed over time

• Current technological options just part of this continuum

• Risks from traditional breeding?

Agricultural systems

• Crop rotation

• Sustainable agriculture

• Sustainable intensification

• Organic

But these are all potentially complementary techniques, not alternatives

Colonisation, migration and agriculture

• Centres of origin vs most productive zones now

• Why are Africa’s staple crops what they are?

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Which of these are “African” crops?

1. Cassava

2. Maize

3. Sorghum

4. Cocoa

5. Oil palm

12%

4%

12%

20%

52%

Which of these are “African” crops?

1. Pearl Millet

2. Mango

3. Rice

4. Sugarcane

5. Cotton

Modern-day crops/foods

• Are often not indigenous

• Have (in the main) been significantly altered by humans over 1000s of years

• And are therefore “genetically modified” (but are NOT GMO’s)

Genetics/Breeding recap

• Natural (genetic) variety/diversity in crops

• Selection (natural, accidental, deliberate)

• Mutation (environmental, genetic)

• Crossing & hybridisation (natural, deliberate)

GENETICS!

Recap

• Agric practices and environments complex

• Planting material/crops complex

– “natural breeding”

– deliberate and accidental breeding

– constant process

• No silver bullets