Potato domestication

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Potato domestication
From The potato treasure of the Andes
Mercedes Ames
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Outline

• Introduction
• Classification of cultivated potatoes
• The origin of the cultivated potato
• Single domestication based on AFLP
• Domestication traits
• The potato in the Andes and Europe

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Introduction
Solanaceae family 4th crop in production
worldwide Range of ploidy 2X, 3X, 4X and
5X High morphological diversity with a great
variety of shapes and colors of tubers
Morphology similarities between wild and
cultivated potatoes
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Introduction
Native of the Andes of South America Landraces
growing from western Venezuela to northern
Argentina and South Central Chile Landrace
populations in Mexico are post-Columbian
introductions
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Classification of cultivated potatoes
3 artificial groups based on use - Wild
(highly diverse) - Cultivated indigenous
(Andes and southern Chile) - Modern
cultivars
Ploidy became a taxonomic trait for cultivated
potato Andean fields contain mixtures of
landraces Hybridization with wild potatoes
S. ajanhuiri (2n2x24) S. chaucha (2n3x36) S.
curtilobum (2n5x60) S. juzepczukii
(2n3x36) S. phureja (2n2X24) S. goniocalyx
(2n2X24) S. stenotomum (2n2X24) S. tuberosum
ssp. tuberosum (2n4X48) ssp. andigenum
(2n4X48)
Most accepted taxonomic treatment
The potato eaters Vincent Van Gogh 1885
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Poor morphological support for previous
classifications
Spooner and Huaman, 2002)
S. tuberosum Only species because -
Reticulate origins - Multiple origins -
Continuous hybridization
Groups classification
Ajanhuiri group Chaucha group Curtilobum group
Juzepczukii group Phureja group Stenotomum
group Chilotanum group ssp. tuberosum Andigenum
group
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Gene pool structure analyses I
Evidences for structure in cultivated potato 4x
adgtbr(chi) 2x phustngonsol 2x ajh 3x
juz 5x cur
From Dr. Marc Ghislains presentation at the 2nd
Solanaceae Genome workshop 2005, Ischia - Italy
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Cluster analysis on 531 landraces x 24 SSR
markers
From Dr. Marc Ghislains presentation at the 2nd
Solanaceae Genome workshop 2005, Ischia - Italy
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From Dr. Marc Ghislains presentation at the 2nd
Solanaceae Genome workshop 2005, Ischia - Italy
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Arguments about the origins of the potato
Juzepczuk and Bukasov
Chilean potato landraces originated from
indigenous primitive chilean 4X wild species
Salaman
S. tuberosum ssp. tuberosum in Chile arose from
ssp. andigenum from the Andes directly or through
a cross with an unidentified wild species

• Cytoplasmic types of chilean landraces of S.
  tuberosum and modern potatoes were identical
• 9 cytoplasmic factors that separate spp.
  andigenum from ssp. tuberosum that cause
  sterility in the presence of specific
  chromosomal genes, abnormal anthers and pollen,
  anthers fused to styles, and female sterility.
  Factors only expressed tbr x adg (Crosses not
  succeed ) and not when adg x tbr (crosses succeed)

Grun origin of the cultivated potato through
selection from a brevicaule-complex and
subsequent hybridization events involving a
number of unknown diploid species.
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Arguments about the origins of the potato
Hawkes identifies S. leptophyes as the
progenitor of S. stenotomum, the species he
designated as the most primitive of the
cultivated species. Thus the cultivated potato
seems to have originated from a group of wild
tuber-bearing Solanum species such as S.
brevicaule, S. leptophyes, S. canasense and
others.
Hawkes 1990. The potato Evolution, Biodiversity
and Genetic Resources
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Hosaka The cpDNA evidences
5 cpDNA genotypes A, C, S, T and W Non of
them specie-specific, but present in different
frequency Andigenum mostly type A Stenotomum
all types but type S more frequent Overlap of
types in Stenotomum, S. bukasovii, S. canasense,
S. candolleanum, S. multidissectum and S.
leptophyes Stenotomum most primitive Ancestral
species complex Tuberosum T type S. tarijense
T-type possible female progenitor of Tuberosum.
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The brevicaule-complex the wild ancestors of the
cultivated potato
First recognized by Ugent as a taxonomically
confusing group of putative ancestors of the
cultivated potato. Endemic to central Peru,
Bolivia and northern Argentina. All of them
show (1) pinnately dissected leaves (2) round
fruits (3) rotate to rotate-pentagonal
corollas (4) largely sexually compatible
(5) EBN matches ploidy (6) 2X, 3X, 6X (7)
grow as weeds and in complexes with cultivated
potatoes

• Only 3 wild taxa recognized
• The peruvian populations
• The Bolivian and the Argentinian
• S. oplocense (Bolivia and Argentina)

Van Den Berg et al. 1988. Am.Journal of Bot.
85(1)92-109
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A single domestication for potato based on AFLPs
(Spooner et al, 2005 PNAS 10241)
Materials and Methods
Wild S. brevicaule complex S. stoloniferum
(4x) Cultivated Phureja group
(2X) Stenotomum group (2X) Andigenum group
(4X) Chilotanum group (4X)
AFLP genotyping Phylogenetic analysis
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Results

• Concordance with morphology defining
• - Northern species from Peru S. achacasense
  (northern Bolivia)
• - Southern species from Bolivia and northern
  Argentina
• Fail to resolve many species within the complex
• Northern
• - S. abancayense, S. bukasovii, S. canasense, S.
  leptophyes, S. marinasense
• S. multidissectum, S. multiinterruptum
• - S. candolleanum and S. pampasense (form
  clades)
• Southern
• - S. ambosinum, S. brevicaule, S. canasense, S.
  leptophyes, S. oplocense, S. sparsipilum, S.
  sucrense
• - S. avilesii, S. hoopesii, S. incamayonense, S.
  spegazzinii, S. ugentii, S. verneii,
• S. vidaurrei (form clades)

S. tarijense previously hypothesized as the
likely maternal contributor to the Chilotanum
group, was group in a different clade with other
related species S. berthaultii and S. chacoense
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Strict consensus parsimony cladogram
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Summarizing the tree
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Single domestication for potato

• All landrace (diploids and polyploids) form a
  monophyletic clade derived from the northern
  members of the S. brevicaule complex.
• S. brevicaule northern group poorly defined,
  maybe they can be reduced to a single species as
  S. bukasovii.
• This single origin differs from previous
  domestication hypotheses in
• (i) a single origin supported here rather than
  a series of multiple independent origins.
• (ii) the origin is confined to the northern
  component of the S. brevicaule complex,
  rather than to other southern complex species
  that have been commonly mentioned as progenitors
  (S. sparsipilum and S. vernei)
• Single origin meaning an origin from a single
  species , or its progenitor S. bukasovii in the
  broad area of southern Peru.
• Potatoes were spread through the Andes from
  Peru both north and south

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Points of discussion

• The use of anonymous markers data to infer
  crop origins ?
• Not all the cultivars groups were included in
  this analysis what about Ajanhuiri Curtilobum
  Chaucha and Juzepczukii groups?
• cp DNA data? Is the effect of gene flow?
  hibridizations?
• What about the relationships among the
  different groups, this origin involved an
  ancestral group ? S. stenotomum?
  polyploidization?

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Domestication syndrome traits in some Solanaceae
Seems to be controlled by a limited number of
genes
Trait Crop
Growth habit / plant architecture/height Tomato
Fruit size Tomato, Egg plant
Fruit morphology Tomato, Egg plant
Plant prickliness Eggplant
It seems that domestication of the Solanaceae has
been driven by mutations in a very limited number
of target loci with major phenotypic effects
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Potato domestication
Selection for above-ground characters Higher
vigor Selection for underground
characters Shorter stolons Larger
tubers Colored and shaped tubers Reduction of
bitter tuber glycoalcaloids a-solanina and
a-chaconina levels in wild species from Series
Tuberosa (S. bukasovii in particular) is
consistent with the occurrence of these compounds
in S. stenotomum and S. tuberosum (chilotanum)
(Johns and Alonso, 1989) But reduction of
glycoalcaloid content not necessarily had to be
direct, either selection for size ( tuber size -
concentration of glycoalcaloids to increase in
water and carbohydrate) or reduced toxicity.
(Johns and Alonso, 1989)
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The Potato in the Andes
1st cultivated potatoes from central Andes of
Peru and Bolivia 6000 1000 years
ago Preferences and selection by individual
farmers may explain some of the diversity of
potato Cultural factors, culinary preferences
and the place of the potato in the Andean
folklore are significant Folk taxonomy is
accurate but it seems to underestimate the actual
diversity
The potato treasure of the Andes from
Agriculture to Culture
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The potato in Europe
First records of potato out of south America
1562 in Canary Islands, Spain Second record
1570 Sevilla, Spain Great social influence
Hypotheses
The potato eaters (www.vggallery.com)

• 1st European modern cultivars were introductions
  of chilean landraces
• 1st modern potatoes were introduced from the
  Andes to Europe as S. tuberosum ssp. andigenum,
  which in Europe rapidly evolve into a wider leaf
  morphology with long-day adaptation.
• Late blight (Phytophtora infestans (Mont.))
  killed most tuberosum-evolved andigenum clones in
  1840s, modern potato was mass selected and bred
  for blight
• 3. Early introduction were from both the Andes
  and from Chile, the Chilean introductions became
  the prominent type before the 1840s.

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Now is almost everywhere.
With the development of modern cultivars
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Thank you!!