According to Andres (1987), Cucurbita pepo L. comprises three subspecies: C. pepo L. ssp. pepo, C. pepo L. ssp. fraterna (L.H. Bailey) Lira et al., and C. pepo ssp. texana (A. Gray) Filov.

According to USDA, ARS, GRIN (2017), C. pepo ssp. pepo is only found in cultivation. C. pepo ssp. fraterna is the probable progenitor (and primary wild relative) of C. pepo ssp. pepo (pepo pumpkin/squash), as well a secondary wild relative of cushaw, C. argyrosperma C. Huber ssp. argyrosperma and moschata pumpkin/squash, C. moschata Duchesne, and a tertiary wild relative of fig-leaf gourd, C. ficifolia Bouche and maxima pumpkin/squash, C. maxima Duchesne (USDA, ARS, GRIN 2017).

According to The Plant List (2013), C. pepo ssp. texana is a synonym of C. pepo var. texana (Scheele) D.S. Decker. USDA, ARS, GRIN (2017) does not list C. pepo ssp. texana (A. Gray) Filov but does list C. pepo ssp. texana (Scheele) Filov, nom. inval. as a synonym of C. pepo ssp. ovifera (L.) D.S. Decker var. texana (Scheele) Filov. This latter taxon is a primary wild relative of pepo pumpkin/squash, as well as a secondary wild relative of cushaw and moschata pumpkin/squash, and a tertiary wild relative of fig-leaf gourd and maxima pumpkin/squash (USDA, ARS, GRIN 2017).

This assessment only relates to the overall population of Cucurbita pepo found in its native wild form (i.e., subpopulations of C. pepo ssp. fraterna and C. pepo ssp. texana). It is globally assessed as Least Concern because although it has a relatively narrow geographic range, the threats that are affecting it are not thought to be reducing it at a level that would warrant its listing in a threatened category. However, it should be noted that although it is common in several sites, more information is required about its population size and trends.

Cucurbita pepo has a native range from the southeast of the United States of America to the northeast of Mexico. There are three recognized subspecies according to Andres (1987) one cultivated and two wild. C. pepo ssp. pepo, widely cultivated in the United States of America, Mexico and Central America, at elevations from sea level to 2,290 m a.s.l., also introduced to Africa, India and Europe; C. pepo ssp. texana, in Texas and along the River Mississippi, in Illinois, Missouri, Oklahoma, Arkansas, Louisiana, Mississippi; and C. pepo ssp. fraterna, growing in the northeast of Mexico, in Nuevo León and Tamaulipas, where it prefers lowlands (at elevations of less than 900 m) (Lira and Montes-Hernandez 1994, Lira and Rodríguez-Arévalo 1999, 2006; Lira et al. 2009a; Gong et al. 2012; Harth et al. 2014; Missouri Botanic Garden 2016; USDA, ARS, GRIN 2017).

Wild populations of this species are endemic to a relatively small area in southeastern United States of America and a few localities in northeastern Mexico (Nuevo León and Tamaulipas), but can be found as a persistent weed in cultivated fields (Decker-Walters et al. 2002, Lira and Caballero 2002, Lira and Rodríguez-Arévalo 2006). Little additional population information is available for this species.

Wild populations grow in dry climates in thornscrub, moist thickets, riparian vegetation, on riverbanks, and in disturbed sites and cultivated fields (Decker-Walters et al. 2002, Lira and Rodríguez-Arévalo 2006, Lira et al. 2009a).

The cultivation of genetically modified squashes (Cucurbita pepo Virus Resistant) in Mexico and in the United States of America is a potential threat to the wild subpopulations of C. pepo as there is a high risk of hybridisation, increasing the weediness and likelihood of extinction of the wild relative. Moreover, C. pepo ssp. fraterna might face the loss of about 80% of the current potential distribution area by 2060 due to the effects of climate change (Arriaga et al. 2006, Lira et al. 2009b, Harth et al. 2014).

Wild subpopulations are potential gene donors to a number of cucurbit crops. Cucurbita pepo ssp. fraterna and C. pepo ssp. ovifera var. texana (syn. C. pepo ssp. texana) are primary wild relatives of pepo pumpkin/squash, secondary wild relatives of cushaw and moschata pumpkin/squash, and tertiary wild relatives of fig-leaf gourd and maxima pumpkin/squash (USDA, ARS, GRIN 2017). Lira and Caballero (2002) and Lira and Rodríguez-Arévalo (2006) specifically highlighted C. pepo ssp. fraterna as a potential source of pest and disease resistance. The subspecies is also used directly for food, medicine and fodder (Lira and Caballero 2002).

This species occurs in the Buffalo National River protected area, Arkansas, United States of America. There are at least 57 accessions of wild source conserved in the North Central Regional PI Station, Ames, Iowa, with duplicates conserved in the National Centre for Genetic Resources Preservation, Fort Collins, Colorado. Additionally, two accessions are conserved at the Millennium Seed Bank, Royal Botanic Gardens, Kew, and one accession is duplicated in the Svalbard Global Seed Vault (Lira et al. 2009b, Genesys Global Portal on Plant Genetic Resources 2016, Information Centre for the Environment 2016, USDA, ARS, GRIN 2017).