Solanum chacoense

Description

Solanum chacoense distribution map
Solanum chacoense distribution map

Solanum chacoense is a very diverse and widely spread species, ranging from Peru south and east into Bolivia, Argentina, Paraguay, Uruguay, and Brazil, where it grows from sea level up to about 6500 feet (2000 m).  Plants are typically between 1 and 2 feet tall, with narrow strongly pointed leaves.  It grows in a wide variety of habitats and is common weed of cultivated ground as well.  Flowers are white.  Berries are ovate to conical, green, sometimes with white spots.  Tubers are typically small, mostly less than an inch, occasionally reaching as much as three inches.  They are usually white to tan in color, less commonly blue, usually with prominent lenticels.

The specific epithet, chacoense, presumably refers to Chaco Province, Argentina.  While there is no completely standardized pronunciation for scientific names, the most common way to pronounce this species is probably so-LAY-num cha-koh-EN-see.  If disregarding the original pronunciation of names or native words, you might instead use the pronunciation kah-koh-EN-see.

Habitat includes riverbanks and fallow fields, sometimes as a weed in cornfields at elevations around 4000 feet (1200 m) (Hawkes 1969).

Although most South American wild potato species are short day tuberizers, some accessions of S. chacoense are able to tuberize under long days.

Subramanian (2017) found that at least some accessions of this species have unusually low calcium and potassium content and unusually high dry matter.

Resistances

Bethke (2017) scored wild potato species as a composite of seven resistance studies and S. chacoense ranked in third place.

Some accessions of S. chacoense deter the feeding of Colorado potato beetle and many other insects due to leptines (acylated glycoalkaloids) in the foliage.  Leptines are not common in S. chacoense and so far have not been found at all in other potato species (Sinden 1986).  Leptines were not found to accumulate in the tubers even when allowed to green (Sinden 1986b).  Sinden (1980) found the least damage from Colorado potato beetle in varieties that had forms of commersonine as their primary glycoalkaloids.

This species can survive frosts down to 26 degrees F (-3.5 C) (Li 1977).  Vega (1995) found that this species is about as frost tolerant as domesticated potato.

Some accessions of this species carry the Rpi-chc1 gene, conferring late blight resistance.

Condition Type Level of Resistance Source
Alternaria solani (Early Blight) Fungus Somewhat resistant Jansky 2008
Clavibacter michiganensis (Ring Rot) Bacterium Somewhat resistant Ross 1958
Drought Abiotic Somewhat resistant Machida-Hirano 2015
Empoasca fabae (Potato Leafhopper) Invertebrate Somewhat resistant Sleesman 1940
Frost Abiotic Somewhat resistant Machida-Hirano 2015
Globodera rostochiensis (Potato Cyst/Golden Nematode) Invertebrate Somewhat resistant Castelli 2003
Globodera pallida (Pale Cyst Nematode) Invertebrate Somewhat resistant Castelli 2003
Globodera pallida (Pale Cyst Nematode) Invertebrate Not resistant Bachmann-Pfabe 2019
Heat Abiotic Somewhat resistant Machida-Hirano 2015
Leptinotarsa decemlineata (Colorado Potato Beetle) Invertebrate Somewhat resistant Stelzner 1943, Schaper 1953, Torka 1943, Machida-Hirano 2015
Liriomyza huidobrensis (Potato Leaf Miner) Invertebrate Somewhat resistant Ochoa 1990
Meloidogyne spp. (Root Knot Nematode) Invertebrate Somewhat resistant Machida-Hirano 2015
Myzus persicae (Green Peach Aphid) Invertebrate Somewhat resistant Adams 1946
Phytophthora infestans (Late Blight) Fungus Not resistant Gonzales 2002
Phytophthora infestans (Late Blight) Fungus Somewhat resistant Machida-Hirano 2015, Bachmann-Pfabe 2019
Ralstonia solanacearum (Bacterial Wilt) Bacterium Somewhat resistant Machida-Hirano 2015
Pectobacterium carotovorum (Blackleg/Soft Rot) Bacterium Somewhat resistant Chung 2011, Machida-Hirano 2015
Metaphorical operculella (Potato Tuber Moth) Invertebrate Somewhat resistant Ochoa 1990
Potato Leafroll Virus (PLRV) Virus Somewhat resistant Ross 1950, Ross 1958, Ochoa 1990
Potato Virus A (PVA) Virus Resistant Wetter 1971
Potato Virus X (PVX) Virus Somewhat resistant Lebedeva 1978, Machida-Hirano 2015
Potato Virus Y (PVY) Virus Somewhat resistant, Resistant Ross 1950, Ross 1958, Ochoa 1990Cai 2011, Machida-Hirano 2015, Wetter 1971
Potato Virus Y (PVY), C Strain Virus Resistant Takacs 1999 (as S. arnezii)
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, Ross 1958
Verticillium spp. (Verticillium Wilt) Fungus Somewhat resistant Lynch 1997

Glykoalkaloid content

The glycoalkaloid composition of S. chacoense varies considerably between accessions.  Sinden (1980), found six different glycoalkaloid profiles for this species: commersonine; solanine; dihydrocommersonine; leptines and commersonine; solanine and chaconine; dihydrosolanine and dihydrochaconine; and leptines with dihydrosolanine and dihydrochaconine.   Sinden (1986b) found TGA levels ranging from 134 to 279 mg / 100 g across three clones of S. chacoense.

Images

Solanum chacoense plant
Solanum chacoense plant
Solanum chacoense flower
Solanum chacoense flower
Solanum chacoense flowers
Solanum chacoense flowers
Flower of the wild potato species Solanum chacoense
Solanum chacoense flower
Berries of the wild potato species Solanum chacoense
Solanum chacoense berries
Tubers of the wild potato species Solanum chacoense
Solanum chacoense tubers
Seedlings of the wild potato species Solanum chacoense
Solanum chacoense seedlings
Tubers of the wild potato species Solanum chacoense
Solanum chacoense ‘M6’ progeny
Plant of the Solanum chacoense variety 'M6'
M6 Solanum chacoense
Flower of the wild potato species Solanum chacoense
Solanum chacoense flower
Flowers of the wild potato species Solanum chacoense
Solanum chacoense potato flowers
Flowers of the wild potato species Solanum chacoense
Solanum chacoense flowers
Berries of the wild potato species Solanum chacoense
Solanum chacoense berries
Berries of the wild potato species Solanum chacoense
Solanum chacoense berries
Tubers of the Solanum chacoense variety 'M6'
Solanum chacoense M6

Cultivation

Bamberg (2017) found a 306% increase in seed set in this species with supplemental applications of liquid fertilizer at four and seven weeks after potting.

Towill (1983) found that seeds of this species stored at 1 to 3 degrees C germinated at 90% after 25 years.

I recommend isolating S. chacoense from domesticated diploids by at least 40 feet if you will be saving seed.  This species appears to be a very effective pollinator and progeny of crosses with diploid S. tuberosum are mostly bitter.

S. chacoense has shown a significant ability to naturalize and become weedy in foreign environments (Simon 2010).  Care should be taken to prevent this species from escaping and growing unmanageably, a precaution that should be taken with all wild potato species until you have experience with them.  There is a lot of rainfall in most of its native range, but it appears to tolerate drought very well.

Trapero-Mozos (2018) determined that this species will tolerate a temperature of 40 C even without prior acclimatization to warm temperatures.

Breeding

Lynch (1997) identified a dominant, single gene source of Verticillium resistance in some accessions of S. chacoense.  This could likely be crossed into S. tuberosum without too much difficulty.

Ochoa (1990) reported that the pollen fertility of triploid S. chacoense (as S. yungasense) was 45-50%, a surprisingly high value for a triploid.

Crosses with S. tuberosum

S. chacoense has been used extensively in potato breeding.  Varieties that include S. chacoense in their pedigrees include Allagash Russet, Atlantic, Belchip, Campbell 11 and 14, Chipbelle, Conestoga, Denali, Islander, Lenape, Norking Russet, Russette, Seminole, Simcoe, Sunrise, Trent, Yankee Chipper, Yankee Supreme (Plaisted 1989), Andover, Chipeta, Mainestay, NorValley, Pike, and Snowden (Love 1999).

Female Male Berry Set
Seed Set Germ Ploidy Source
S. chacoense S. tuberosum 2x Yes Yes Ochoa (1990)
S. chacoense S. tuberosum 4x None None Jackson (1999)
S. tuberosum 2x S. chacoense Yes Yes Ochoa (1990)
S. tuberosum 4x S. chacoense Low Low Jackson (1999)

Crosses with other species

Jackson (1999) found 2-11% 2n pollen for this species.

Female Male Berry Set
Seed Set Germ Ploidy Source
S. chacoense S. berthaultii High High Ochoa (1990)
S. chacoense S. brevicaule (as S. vidaurrei) Yes Yes Ochoa (1990)
S. commersonii
S. chacoense
Yes Yes Yes 2x Propach 1940
S. commersonii
S. chacoense
No Hawkes 1969

Cultivars

M6

M6 is an improved variety of S. chacoense, introduced in 2014.  It was produced by seven generations of self pollination beginning with an S. chacoense accession bearing the Sli gene. It is homozygous for the Sli gene, able to self-pollinate and produce vigorous progeny, and is a day neutral tuberizer.  M6 can be used in breeding with domesticated diploids to reliably introduce self-compatibility, since the Sli gene is dominant.  M6 may not be pure S. chacoense, likely having hybridized at some point in its ancestry (Clot 2020).

References

Solanum chacoense at Solanaceae Source

Solanum chacoense at GRIN Taxonomy

Solanum chacoense at CIP