Transcript Veg Crops-Lesson 03 Domest Classif

Vegetable Crops – PLSC 451/551
Lesson 3, Domestication, Classification.
Instructor:
Stephen L. Love
Aberdeen R & E Center
1693 S 2700 W
Aberdeen, ID 83210
Phone: 397-4181 Fax: 397-4311
Email: [email protected]
Origin, Evolution
Nikolai Ivanovich Vavilov
Most of the varietal wealth in our
crop plants was concentrated in
eight great centers of diversity:
China, Hindustan, Central Asia, Asia
Minor, the Mediterranean region,
Abyssinia, Central America, westcentral S. America
Fig. 2.1 Centers of Origin
Origin, Evolution
Nikolai Ivanovich Vavilov
Centers of origin of species coincide with the
areas where the greatest diversity exists in
the species.
Origin, Evolution
Nikolai Ivanovich Vavilov
Secondary centers of origin (centers of
diversity) may be found far removed from
the primary center of origin.
These may be associated with domestication
and human movement
Centers of Origin
Determination of centers:
Botanical evidence
Archeological evidence
Historical evidence
Linguistic evidence
(Last 3 more likely to determine center of
domestication)
Centers of Origin
Features:
Geographical location of species origin
Site of maximum adaptation
Site of maximum diversity
Presence of related species
Usually associated with site of domestication
cabbage
carrot
celery
lettuce
beet
corn, bean
pumpkin, tomato
pepper
potato
watermelon
okra
cantaloupe
lettuce, turnip
onion
cucumber
manioc
sweet potato
Vavilov’s Centers of Diversity (origin)
eggplant
Centers of Origin – Major Crops
Lettuce – Europe and Asia
Cabbage – Europe
Beet – Europe
Carrot – Europe and Asia
Onion – Asia
Potato – South America
Sweet Potato – South America
Bean – South America
Centers of Origin – Major Crops
Pea – Europe and Asia
Tomato – Central America
Pepper – Central and South America
Cucumber – Asia and Africa
Cantaloupe – Asia
Watermelon – Africa
Squash – Central and North America
Sweet Corn – Mexico?
Edible species
20,000
Species used
for food
3,000
Species cultivated
200
Major
crop
species 25
Crop Species Domestication
Began 8-10,000 years ago
Process
Foraging and unintentional selection
Early cultivation
Domestication
Intensified and large scale production
Foraging
Impact of foraging and plant management
Selection of best food types – seed
distribution
Selection of best adapted types in habitat
region
Unintentional altering of habitat to promote
growth of certain plants (i.e. burning)
Early Cultivation
Began as man approached food production
systematically
Started as unintentional habitat alteration
to favor desired species
Led to more intense cultivation; form
depended on geographical constraints
Early Cultivation
Favored in tropical regions:
Vegetatively propagated plants
re-growth from remnants
no dormancy
discarded propagules in refuse piles
Early Cultivation
Favored in mountainous or
temperate regions:
Seed propagated plants
collected seeds may fall, germinate
(after rain) around settlements
eventually seed were actively stored
and systematically planted
Early Cultivation
Impact of early cultivation on crop species
Deliberate care of preferred plants
Preferential survival of edible crop plants
Distribution to new areas of habitat
Increased population of humans and thus
populations of crop species
Domestication
Plant/human co-development (Fuller, WorldPress.com)
Domestication
Years BC
Domestication
Characteristics of wild species:
Edible parts small, fibrous, bitter
Numerous seeds, rapidly dispersed
Poor or non-uniform seed emergence
Often contain toxic compounds
Domestication
Changes in maize
North American marsh elder
Domestication
Changes in plants as a result of selection:
Gigantism
often a result of changes in PLOIDY
Where PLOIDY reflects the number of
chromosomes in a SOMATIC cell
(somatic versus gametic)
Domestication
Terms of Ploidy:
monoploid – has only a single
complement of a basic chromosome
set of the species
also referred to as the haploid state
(gamete cells)
Domestication
Terms of Ploidy:
diploid – has two complete sets of the
basic chromosome number of the
species
Domestication
Terms of Ploidy:
diploid – has two complete sets of the
basic chromosome number of the
species
triploid
tetrapoid
pentaploid
hexaploid
Domestication
Examples of Ploidy:
diploid – corn, onion, lettuce, tomato
triploid – taro, watermelon (seedless)
tetraploid – cassava, potato,
hexaploid – yams, sweet potato
Domestication
Changes in seed as a result of selection:
Size
Uniformity of germination
# of seeds per plant
Shattering
Dormancy
Hardness of seed coat
Domestication
Other morphological and physiological
changes resulting from selection
Loss of survival traits
Loss of photoperiod response (potato)
Emergence of mutant types (brassica)
Absence of toxic substances (tomato)
Domestication – Bean Example
Trait
Wild
Seed dispersal
present
Pod wall fibers
present
Seed dormancy
70% germ.
Growth habit
indeterminate
Number of pods
43.2
Pod length
5.7 cm
Seed weight (100) 3.5g
Days to flower
69
Harvest index
0.42
Flower delay (16 hr) >60 days
Domesticated
absent
absent
100% germ
determinate
7.5
9.3 cm
19.5g
46
0.62
0 days
Example of selected diversity in squash
Example of wild species in potatoes
Example of selected diversity in potato
Domestication
Impact of Domestication on crop species
Selection of useful traits within crop species
Elimination of survival traits resulting in
dependence on human culture
Wider distribution and adaptation
Intense Cultivation
Defined as controlled crop production:
Includes:
tillage
planting and transplanting
weed and pest control
harvest and sometimes storage
Bolivian crop terraces
From Correll, 1962
Intense Cultivation
Result of intensified cultivation
Selection for traits resulting in
economic benefit to the producer –
directed breeding
Ease of management
Storability
Shipability
Market specific quality traits
Intense Cultivation
Age-old question
“I can’t buy a good tomato any more!”
Is the complaint valid that produce has lost
quality as we concentrate on economic
production factors?
Classification
Process of lumping numerous crop
species into useful categories
Classification
Classified by:
Adaptation and hardiness
Classification
Classified by environmental adaptation:
Warm-season (very tender)
Cucumber
Eggplant
Lima bean
Muskmelon
Okra
Pepper
Pumpkin
Squash
Sweet potato
Watermelon
Classification
Classified by environmental adaptation:
Warm-season (tender)
Cowpea
Snap bean
Soybean
Sweet corn
Tomato
Classification
Classified by environmental adaptation:
Cool-season (semi-hardy)
Beet
Carrot
Cauliflower
Celery
Swiss chard
Lettuce
Parsnip
Potato
Classification
Classified by environmental adaptation:
Cool-season (hardy)
Cabbage
Broccoli
Brussel sprouts
Califlower
Onions
Leeks
Pea
Radish
Garlic
Asparagus
Classification
Classified by:
Adaptation and hardiness
Life Cycle
Classification
Classified by life cycle
Perennial
Asparagus, rhubarb, sweet potato
Biennial
Beet, broccoli, carrot, onion, parsley
Annual
Cucumber, tomato, spinach, sweet corn
Classification
Classified by:
Adaptation and hardiness
Life cycle
Parts used for food
Classification
Classified by edible portion:
Root – beet, carrot, turnip
Bulb – leek, onion, garlic
Stem – asparagus, kohlrabi
Flower – cauliflower, broccoli
Tuber - potato
Classification
Classified by edible portion:
Immature fruit – cucumber, sweet corn
Mature fruit – watermelon, tomato,
squash
Leaf – cabbage, lettuce, spinach
Petiole – celery
Seed – beans, pumpkin seed
Classification
Classified by:
Adaptation and hardiness
Method of culture
Parts used for food
Taxonomic grouping (next lecture)