II.2. SQUASHES, PUMPKINS, ZUCCHINIS, GOURDS (CURCURBITA SPECIES) – 93
domestications, one in Mexico and the other in northern South America. This hypothesis
is supported by linguistic evidence – i.e. C. moschata is known by native names specific
to the language used in each region (Lira, Andres and Nee, 1995; Robinson and
Decker-Walters, 1997; Decker-Walters and Walters, 2000).
After its domestication, it is likely that C. moschata spread through the Caribbean
Islands, giving rise to various native cultivars (Robinson and Decker-Walters, 1997;
Piperno, Andres and Stothert, 2000). After the European contact, C. moschata was spread
rapidly to other continents, adapting to different ecological conditions. C. moschata was
being cultivated at the end of the 17th century in western Mississippi (United States), and
in the 19th century in Angola, India, Java, Northern Africa and Japan, where the species
diversified (Sauer, 1993; Lira, Andres and Nee, 1995; Decker-Walters and Walters,
2000). Wu et al. (2011) report the existence of 1 032 landrace accessions of C. moschata
in the People’s Republic of China, hereafter “China”), reflecting a large diversity in
landraces developed in China. C. moschata accessions are among the best represented
Cucurbita accessions at the genebank of the Center for the Conservation and Breeding of
Agricultural Diversity (COMAV) at the Polytechnic University at Valencia, Spain with a
strong representation of landraces still cultivated under traditional cropping systems
(Esteras et al., 2008). In Spain the cultivation of this species is mainly based on landraces
maintained for centuries. Ferriol et al. (2004) examined 47 COMAV accessions from the
Spanish peninsula, the Canary Islands, and Central and South America. The
morphological characterisation showed considerable variability. Molecular analysis using
amplified fragment length polymorphism and sequence related amplified polymorphism
markers showed a genetic variability concordant with the morphological variability
(Ferriol et al., 2004). In addition, C. moschata is the best represented Cucurbita in gene
banks of the Americas (e.g. Center for International Food and Agricultural Policy
[CIFAP] in Mexico). C. moschata is also one of the most important vegetables cultivated
in Malawi, Zambia and tropical Africa, where its cultivation is mainly based on landraces
with a high degree of autogamy (Gwanama, Labuschagne and Botha, 2000). These
landraces have adapted to a variety of climatic conditions and soil types (Gwanana,
Labuschagne and Botha, 2000). In general, C. moschata is the most widely cultivated
Cucurbita in the tropics, where it is primarily grown on a small-scale basis for local
consumption (Andres, 2004). These findings indicate that for C. moschata, in addition to
the diversity seen in the Americas, multiple centres of diversity, primarily composed of
landraces, exist around the world.
Cucurbita pepo
The natural distribution of C. pepo ranges from the eastern United States north into
the state of Illinois through the Mississippi Valley, through the state of Texas and south
into Mexico (Table 2.1). The archeological record, summarised in Table 2.2, shows that
C. pepo initially became a fundamental element of agriculture in the Americas in the
highlands of Mexico thousands of years ago (Smith, 1986). The most ancient remains of
this species have been found in the Valley of Oaxaca (8750 BCE-700 CE) in the Ocampo
caves, in the state of Tamaulipas in northeast Mexico (Table 2.2). The appearance of
C. pepo in the United States as a domesticated crop also dates back thousands of years
(King, 1985) as supported by the archaeological record which indicates C. pepo was
being used by native populations thousands of years ago (7000-5000 BCE; Table 2.2)
in what is now west central Illinois (United States). According to archaeological records,
C. pepo appears to be one of the first domesticated species of Cucurbita, with a
domestication even older than that attributed to other important domesticated crops: