Phylogenetics of the genus Sechium P. Brown: A review

The Sechium P. Br. genus composed of 11 species, which originated from the mountainous regions of Mesoamerica, have been domesticated and diversified. These species are clustered in two large groups: the Mexican clade and the Central American clade. Morphological and molecular studies have shown that species of the Mexican clade are formed through interspecific hybridizations and genetic flow, with the exception of S. mexicanum, which is strongly linked to the genus Sicyos. The objective of this review was to analyze the phylogenetics of Sechium based on morphological and molecular studies, which contributed to taxonomic knowledge and utilization, thereby favoring its conservation and improvement. The Central American clade is well supported with molecular data, but not so with morphological data. The species in this clade were geographically isolated and endemic. S. edule and S. tacaco are exploited species in the agricultural and industrial sectors, and both have an extensive genetic and phenotypic diversity that has allowed them to diversify and expand into different ecological niches. Finally, the Central American species of Sechium thrive in adverse environments of temperatures of mesophyll forest and high relative humidity, with characteristics that can give resistance to frosts and phytopathogenic agents, as well as cultivated species of this genus.