Solanum commersonii

Description

Solanum commersonii distribution map
Solanum commersonii distribution map

Solanum commersonii is a species of Argentina, Paraguay, Uruguay, and Brazil.  Plants are low growing and often rosette like, with what I would describe as a “weedy” appearance.  Flowers are small, stellate, white to purple, but usually more colorful on the back than the front.  Berries are long and tapering.  Tubers are usually small and while with moderately deep eyes, but tubers as large as 4.7 x 2.4 inches (12 x 6 cm) have been reported.  According to Hawkes, this was the first wild potato species to be named and described and the first collected on a scientific expedition.  The specific epithet, commersonii, honors French naturalist Philibert Commerson, who collected the type specimen.

In its native range, S. commersonii is a widespread, weedy plant, growing in a variety of habitats from sea level to 1300 feet (400 m) (Hawkes 1969).  It is noted to grow near to the sea, in rocky areas and dunes, which suggests some salt tolerance.

There are reports of this species being cultivated as an edible in France in the early twentieth century, where it produced “abundant, large, and palatable” tubers (Newman 1904).  Reddick (1939) reported tubers of large, commercial size in an early evaluation of this species.  A purple variety called ‘Violett’ appeared in European seed catalogs as early as 1908.  According to Hawkes (1969), there may be reason for some skepticism about these claims, as S. tuberosum material was apparently mistaken for S. commersonii on more than one occasion.

S. commersonii is one of the few wild potato species for which the genome has been sequenced (Aversano 2015).  Sequencing revealed that this species is dramatically less heterozygous than the domesticated potato (1.5% vs 53-59%).  There are a number of possible reasons for this, including that the accession that was sequenced has been maintained in isolation and that the domesticated potato may have an unusual high level of heterozygosity as the result of modern breeding.

Resistances

This species can survive frosts down to 23 degrees F (-5 C) (Li 1977).  Vega (1995) found that this species is more frost tolerant than domesticated potato and nearly as tolerant as S. acaule.  Genomic analysis revealed that this species upregulates production of galactinol synthase, which has been associated in other species with the production of raffinose oligosaccharides that can protect against osmotic stress (for example, stresses caused by frost exposure) (Aversano 2015).

In a study of early blight resistance, Jansky (2008) found that S. commersonii was one of the top three most resistant species tested.

Condition Type Level of Resistance Source
Alternaria solani (Early Blight) Fungus Somewhat resistant Jansky 2008
Frost Abiotic Resistant Machida-Hirano 2015
Globodera pallida (Pale Cyst Nematode) Invertebrate Not resistant Castelli 2003
Globodera pallida (Pale Cyst Nematode) Invertebrate Not resistant Bachmann-Pfabe 2019
Globodera rostochiensis (Potato Cyst/Golden Nematode) Invertebrate Resistant Castelli 2003
Leptinotarsa decemlineata (Colorado Potato Beetle) Invertebrate Somewhat resistant Machida-Hirano 2015
Meloidogyne spp. (Root Knot Nematode) Invertebrate Somewhat resistant Machida-Hirano 2015
Pectobacterium carotovorum (Blackleg/Soft Rot) Bacterium Somewhat resistant Chung 2011, Machida-Hirano 2015
Phytophthora infestans (Late Blight) Fungus Somewhat resistant Gonzales 2002
Phytophthora infestans (Late Blight) Fungus Somewhat resistant Bachmann-Pfabe 2019
Potato Virus X (PVX) Virus    
Potato Virus Y (PVY) Virus Not resistant Cai 2011
Sclerotinia sclerotiorum (White Mold) Fungus Resistant Jansky 2006
Streptomyces scabiei (Scab) Bacterium Somewhat resistant Machida-Hirano 2015
Streptomyces scabiei (Scab) Bacterium Immune Reddick 1939
Synchytrium endobioticum (Wart) Fungus Somewhat resistant Machida-Hirano 2015
Tobacco Etch Virus (TEV) Virus    
Verticillium spp. (Verticillium Wilt) Fungus    

Glykoalkaloid content

Carputo (2003) found a value of 48.1 mg / 100g for this species, a level more than double the safety limit, with three glycoalkaloids: dehydrodemissine, dehydrotomatine, and dehydrocommersine.  Gregory (1981) found a TGA value of 23 mg/g dry weight, which should translate into roughly 230 mg / 100g fresh, a very high amount.

I have tasted a random sampling of tubers from seed grown plants of these species and found them all palatable.  That seems like good luck, or perhaps some of the glycoalkaloids in this species are not as bitter as the more common solanine and chaconine.  Most accounts report that the tubers are bitter and the Uruguayan name “papa purgante,” suggests that this is likely to be a defining characteristic of the species.

Images

Above ground plant of the wild potato species Solanum commersonii
Solanum commersonii plant
Above ground plant of the wild potato species Solanum commersonii
Solanum commersonii plant
Above ground plant of the wild potato species Solanum commersonii
Solanum commersonii plant
Commerson Potato (Solanum commersonii) Magazine Clipping
Solanum commersonii Magazine Clipping
 
Above ground plant of the wild potato species Solanum commersonii
Solanum commersonii plant
 
Flower of the wild potato species Solanum commersonii
Solanum commersonii flower
 
Inflorescence of the wild potato species Solanum commersonii
Solanum commersonii inflorescence
Flower of the wild potato species Solanum commersonii
Solanum commersonii flower
Back of the flower of the wild potato species Solanum commersonii
Solanum commersonii flower back
Back of the flower of the wild potato species Solanum commersonii
Solanum commersonii flower back
Berries of the wild potato species Solanum commersonii
Solanum commersonii berries
Berries of the wild potato species Solanum commersonii
Solanum commersonii berries
Berries of the wild potato species Solanum commersonii
Solanum commersonii berries
Berries of the wild potato species Solanum commersonii
Solanum commersonii berries
Tubers of the wild potato species Solanum commersonii
Solanum commersonii tubers
 
 
 

Cultivation

Chen (1976) found that this species reaches its maximum frost resistance (about 11 degrees F, -11.7 C) following a three week period of shortening photoperiod and reducing day and night temperatures.

Bamberg (1995) found that at least some accessions of S. commersonii flower better at high temperatures than under typical temperate growing conditions.  Flowering was better when greenhouse temperatures exceeded 100 degrees F for several hours during the day.

I have noticed that berries of this species are easily dislodged, even before they are mature.  My normal practice is to give a little shake to each inflorescence and harvest any berries that fall off; with this species, even young berries tend to drop.  It might be a good idea to tie up or otherwise support inflorescences and to shelter the plants from strong wind for greater yield.  This species also produces many seedless, parthenocarpic berries, so seed yields can be surprisingly low.

Breeding

Watanabe (1991) found that 4.8% of varieties of this species produced 2n pollen and Jackson (1999) found 1-10%, which would be effectively tetraploid and 2EBN.

Crosses with S. tuberosum

Female Male Berry Set
Seed Set Germ Ploidy Source
S. commersonii
S. tuberosum 2x
Yes Yes Yes   Emme 1937
S. commersonii S. tuberosum 4x
None None     Jackson 1999
S. commersonii 3x
S. tuberosum 4x Yes Yes Yes   Bukasov 1940
S. commersonii 3x S. tuberosum 4x Yes Yes Yes   Perlova 1945
S. tuberosum S. commersonii Minimal None     Jackson 1999

Crosses with other species

Hawkes (1969) noted that, although their ranges overlap, there appear to be few wild hybrids between S. commersonii and S. chacoense.

Female Male Berry Set
Seed Set Germ Ploidy Source
S. commersonii
S. berthaultii (as S. tarijense)
Yes No     Hawkes 1969
S. commersonii 3x S. demissum Yes Yes Yes   Reddick 1939, Black 1945
S. commersonii
S. jamesii
Yes Yes     Reddick 1939
S. commersonii S. brevicaule (as S. spegazzini)
Yes Yes Yes   von Olah 1938
S. commersonii S. brevicaule (as S. spegazzini)
Yes Yes Yes 2x Propach 1940
S. commersonii
S. chacoense
Yes Yes Yes 2x Propach 1940
S. commersonii
S. chacoense
No       Hawkes 1969
S. commersonii 3x S. x edinense
Yes Yes Yes   Broili 1921
S. commersonii
S. kurtzianum
Yes Yes Yes   Perlova 1945
S. commersonii 3x S. stoloniferum
Yes Yes Yes   Vavilov 1938
S. commersonii 3x S. stoloniferum Yes Yes Yes   Emme 1937
S. commersonii S. verrucosum Yes Yes Yes 2x Propach 1940
S. commersonii S. wittmackii Yes Yes Yes 2x Propach 1940
S. commersonii
S. stoloniferum (as S. fendleri) Yes Yes     Reddick 1939
S. stoloniferum (as S. fendleri) S. commersonii Yes Yes     Reddick 1939

References

Solanum commersonii at Solanaceae Source

Solanum commersonii at GRIN Taxonomy

Solanum commersonii at CIP

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One thought on “Solanum commersonii

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    Barry W. B says:

    I want to know what gene or genes are responsible for the tubers in these plants (potatoes and commerson’s nightshade).

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