Solanum verrucosum

Description

Solanum verrucosum (verrucosum means warty) is a widespread species in Mexico, where it is primarily a plant of woodlands and cloud forests.  Plants about 6 to 18 inches tall.  Blue flowers.  Round berries. 

Tubers of this species are or were occasionally eaten in Mexico, according to notes from various collecting expeditions.  Correll (1962) also reports that this species was once cultivated near Geneva, Switzerland, in the hope that it would resist late blight, but eventually abandoned due to the small tuber size and late bearing.

This species is remarkable for its self-compatibility, although inbred lines do suffer from inbreeding depression as expected in diploids of this genus (Abdalla 1973). Self compatibility is rare in diploid potatoes and has only been otherwise observed in S. polyadenium and certain lines of S. chacoense that possess self-incompatibility inhibition (sli) alleles.

S. verrucosum is suspected as the progenitor of all Mexican polyploid species, based upon the presence of a mitochondrial marker (Sanetomo 2013).  It is the only North American diploid species with the A genome.

Resistances

This species can survive frosts down to 27 degrees F (-3 C) (Li 1977).  Vega (1995) found that this species is about as frost tolerant as domesticated potato.

Some accessions of this species carry the RB gene, conferring late blight resistance.

Condition	Type	Level of Resistance	Source
Alternaria solani (Early Blight)	Fungus	Somewhat resistant	Jansky 2008
Globodera pallida (Pale Cyst Nematode)	Invertebrate	Not resistant	Bachmann-Pfabe 2019
Globodera pallida (Pale Cyst Nematode)	Invertebrate	Not resistant	Castelli 2003
Globodera rostochiensis (Potato Cyst/Golden Nematode)	Invertebrate	Not resistant	Castelli 2003
Pectobacterium carotovorum (Blackleg/Soft Rot)	Bacteria	Somewhat resistant	Chung 2011
Phytophthora infestans (Late Blight)	Fungus	Somewhat resistant
Phytophthora infestans (Late Blight)	Fungus	Somewhat resistant	Bachmann-Pfabe 2019
Phytophthora infestans (Late Blight)	Fungus	Some resistance	Karki 2020
Potato Virus Y (PVY)	Virus	Not resistant	Cai 2011

Glykoalkaloid content

Images

Cultivation

Towill (1983) found that seeds of this species stored at 1 to 3 degrees C germinated at 100% after 27 years.

Breeding

Crosses with S. tuberosum

Watanabe (1991) found that 4.1% of varieties of this species produced 2n pollen, which would be effectively tetraploid and 4EBN.

Female	Male	Berry Set	Seed Set	Ploidy	Germ	Source
S. tuberosum	S. verrucosum	Minimal	None			Jackson (1999)
S. verrucosum	S. tuberosum	None	None			Jackson (1999)
S. verrucosum	S. tuberosum 2x	Moderate	Moderate	High		Abdalla 1973

Crosses with other species

Jackson (1999) found 4-11% 2n pollen for varieties of this species.

Abdalla (1973) observed that interspecies crosses in which S. verrucosum is used as the male parent are rarely successful.  In addition, cytoplasmic sterility renders the majority of the progeny male sterile when S. verrucosum is used as the female parent.

Female	Male	Berry Set	Seed Set	Ploidy	Germ	Source
S. commersonii	S. verrucosum	Yes	Yes	Yes	2x	Propach 1940
S. verrucosum	S. chacoense	High	High	Low		Abdalla 1973
S. verrucosum	S. chomatophilum	Low	Moderate	High		Abdalla 1973
S. verrucosum	S. infundibuliforme	High	High	Moderate		Abdalla 1973
S. verrucosum	S. raphanifolium	High	Low	High		Abdalla 1973
S. verrucosum	S. berthaultii (as S. tarijense)	High	Moderate	Minimal		Abdalla 1973
S. verrucosum	S. candolleanum (as S. canasense and S. multidissectum)	High/Moderate	Low/Moderate	Low/Moderate		Abdalla 1973
S. verrucosum	S. kurtzianum	High	High	High		Abdalla 1973
S. verrucosum	S. brevicaule (as S. leptophyes)	High	Low	Low		Abdalla 1973
S. verrucosum	S. microdontum (as S. gigantophyllum)	Moderate	Moderate	High		Abdalla 1973
S. verrucosum	S. vernei	High	Moderate	High		Abdalla 1973

References

Solanum verrucosum at Solanaceae Source

Solanum verrucosum at GRIN Taxonomy