Solanum cajamarquense

Description

Solanum cajamarquense distribution map
Solanum cajamarquense distribution map

Solanum cajamarquense is an unusual speces, with a small distribution in northern Peru.  It grows at mid-elevations of the Andes from about 6500 to 8500 feet.  Plants roughly 16 to 20 inches tall.  Stolons long, exceeding two feet.  Tubers small and moniliform, like beads on a string.  Flowers white.  Berries small, less than 1/2 inch, round, striped.  The specific epithet, cajamarquense, refers to Cajamarca Department, Peru.

Li (2018) placed this species in Clade 3, a group of Andean diploids, but closely neighboring Clade 1+2, North American 1EBN diploid species.

Resistances

S. cajamarquense appears to have unique late blight resistance genes (Lindqvist-Kreuze 2010).  Vega (1995) found that this species is about as frost tolerant as domesticated potato.

Some plants of this species produce very heavy trichomes, which presumably acts as an insect deterrent.

Condition Type Level of Resistance Source
Phytophthora infestans (Late Blight) Fungus Resistant Gonzales 2002, Perez 2007

Glykoalkaloid content

Images

Solanum cajamarquense seedling
Solanum cajamarquense seedling
Solanum cajamarquense plant
Solanum cajamarquense plant
Solanum cajamarquense plant
Solanum cajamarquense plant
Solanum cajamarquense plant
Solanum cajamarquense plant
Solanum cajamarquense flower
Solanum cajamarquense flower
Solanum cajamarquense flowers
Solanum cajamarquense flowers
Above ground plant of the wild potato species Solanum cajamarquense
Solanum cajamarquense plant
Heavy trichome development on the wild potato species Solanum cajamarquense
Solanum cajamarquense trichomes
Flower of the wild potato hybrid S. cajamarquense x S. boliviense
S. cajamarquense x S. boliviense flower
Flower buds of the wild potato species Solanum cajamarquense
Solanum cajamarquense flower buds
Aerial plant of a S. cajamarquense x S. boliviense hybrid
S. cajamarquense x S. boliviense hybrid
Four plants of the wild potato species Solanum cajamarquense
Solanum cajamarquense (four plants)
Leaf variation in a S. cajamarquense x S. boliviense hybrid. S. boliviense on the right, S. cajamarquense on the left, three hybrids in between.
Leaf variation in a S. cajamarquense x S. boliviense hybrid. S. boliviense on the left, S. cajamarquense on the right, three hybrids in between.
Flowers of a Solanum cajamarquense x Solanum boliviense hybrid
S. cajamarquense x S. boliviense hybrid
Flowers of the wild potato species Solanum cajamarquense
Solanum cajamarquense flowers
 

Cultivation

I have found germination of this species to be very slow, taking between one and three months.  I haven’t had much luck getting tubers bigger than pinheads from this species, even when the plants are left to grow into November or December.

The pesticide carbofuran has been observed to reduce flowering in this species (Centeno-diaz 2007).

Accessions Evaluated

The following accessions were examined to prepare this profile.  I have evaluated 2/2 accessions currently available from the US Potato Genebank.

PI 230522

Poor germination and relatively slow seedling growth.  Dark colored seedlings.  Leaves with purple undersides.  Some with purple veins as well.  Some with lots of very pretty blue flowers.  The GRIN page for this accession lists it as S. cajamarquense, but also indicates that it is hybrid seed with PI 275149, which is an accession of S. boliviense.  I inquired with the genebank and they confirmed that it is a hybrid and also provided data showing that most attempts at seed increases have failed.  They also confirmed that this accession has counted out as diploid in root tip counts.  This cross would presumably produce triploid (2/3 CJM and 1/3 BOL) progeny and the plants did not produce berries here when pollinated by true S. cajamarquense, which is consistent with that. A diploid result from this cross does not make sense to me, due to the differences in EBN.  My best guess is that the original hybrids were triploid and 2EBN.  Perhaps those were bulked together for seed, giving aneuploids between diploid and triploid and stabilizing toward diploid.  This often seems to be the case with interspecies odd-ploidy hybrids.

I also noticed that Binquan (2019) reported that this accession grouped in such a way that it suggested introgression from clade 4, which is consistent with its hybrid nature.

PI 310988

Good germination and relatively strong seedling growth.  Light colored, pubescent seedlings.  Leaves with green undersides.

Breeding

Crosses with S. tuberosum

Female Male Berry Set
Seed Set Germ Ploidy Source
             

Crosses with other species

Female Male Berry Set
Seed Set Germ Ploidy Source
             

References

Solanum cajamarquense at Solanaceae Source

Solanum cajamarquense at GRIN Taxonomy

Solanum cajamarquense at CIP

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