Potato domestication
From: The potato treasure of the Andes
Mercedes Ames
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
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
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 postColumbian introductions
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 (2n=2x=24)
S. chaucha (2n=3x=36)
S. curtilobum (2n=5x=60)
S. juzepczukii (2n=3x=36)
S. phureja (2n=2X=24)
Most accepted taxonomic treatment
S. goniocalyx (2n=2X=24)
“The potato eaters”S.Vincent
Van Gogh
1885
stenotomum
(2n=2X=24)
S. tuberosum
ssp. tuberosum (2n=4X=48)
ssp. andigenum (2n=4X=48)
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
Gene pool structure analyses I
Evidences for structure in cultivated potato:
4x adg+tbr(chi) – 2x phu+stn+gon+sol – 2x ajh – 3x juz – 5x cur
From Dr. Marc Ghislain’s presentation at the 2nd Solanaceae Genome workshop 2005, Ischia - Italy
Cluster analysis on 531 landraces x 24 SSR markers:
From Dr. Marc Ghislain’s presentation at the 2nd Solanaceae Genome workshop 2005, Ischia - Italy
From Dr. Marc Ghislain’s presentation at the 2nd Solanaceae Genome workshop 2005, Ischia - Italy
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.
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.
Wild
species
Cultivated
species
S. acaule
(4X)
S. sparsipilum
(2X)
S. leptophyes
(2X)
S. tuberosum
ssp. andigena
(4X)
S. stenotomum
(2X)
S. megistacrolobum
(2X)
S. ajanhuiri (Yari)
(2X)
S.
chaucha
(3x)
S. curtilobum
(5X)
(Ajawiri)
S. phureja
(2X)
S. juzepczukii
(3X)
Hawkes 1990. The potato: Evolution, Biodiversity and
Genetic Resources
Hosaka : The cpDNA evidences
5 cpDNA genotypes: A, C, S, T and W
T
W
A
C
S
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.
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:
a) The peruvian populations
b) The Bolivian and the Argentinian
c) S. oplocense (Bolivia and Argentina)
Van Den Berg et al. 1988. Am.Journal of Bot. 85(1):92-109
A single domestication for potato based on AFLPs
(Spooner et al, 2005 PNAS 102:41)
Materials and Methods:
362 accessions total
261 wild
98 landraces
Sect. Petota
S. etuberosum
S. palustre
Sect. Etuberosum
Wild:
S. brevicaule complex
S. stoloniferum (4x)
Cultivated:
Phureja group (2X)
Stenotomum group (2X)
Andigenum group (4X)
Chilotanum group (4X)
AFLP genotyping
Phylogenetic analysis
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
Strict consensus parsimony cladogram
Summarizing the tree
Southern Brevicaule group plus
other species
Cultivated species
Northern Brevicaule group
Clade 3
Outgroups
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
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?
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
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
α-solanina and α-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)
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
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)
1. 1st European modern cultivars were introductions of chilean landraces
2. 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 1840’s, 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 1840’s.
With the development of modern cultivars …. Now is almost everywhere….
Fondazione Slow Food per la Biodiversità
Thank you!!