Work

Morphological and genetic diversity of Carica papaya (L.) natural populations in the fragmented landscapes of southern Mesoamerica

Year: 2026

Type: article

Abstract: Crop wild relatives (CWR) are valuable genetic reservoirs for crop improvement because they may harbor alleles conferring disease resistance and environmental tolerance. A major threat to the genetic diversity of CWR is habitat fragmentation, which can isolate populations and reduce gene flow. Carica papaya L. is cultivated worldwide, yet wild populations persist throughout Mesoamerica, its region of origin, where they occur along roadsides, in abandoned fields, and in secondary lowland forests. We quantified morphological and genetic diversity in wild papaya populations from northwest Costa Rica and western Nicaragua. Wild papaya consistently produce small, seedy, yellow fruits, whereas vegetative traits, including leaf shape and size, are more phenotypically plastic. Genetic analyses of naturally-occurring populations revealed moderate levels of diversity, structured into three primary population clusters; two of these clusters are centered in Costa Rica, and the third is primarily in the western coastal region of Nicaragua. Landscape connectivity was reduced across much of the study area due to habitat fragmentation, with the notable exception of the Nicoya Peninsula, which retains larger areas of contiguous forest. We conclude that wild papaya represents a valuable genetic resource for breeding programs; however, this diversity is increasingly threatened by habitat fragmentation that limits gene flow and promotes inbreeding. Conservation efforts should prioritize preserving germplasm from each of the three population clusters, with highest priority given to populations in regions of high landscape connectivity and minimal urban influence.

Source: Genetic Resources and Crop Evolution

DOI: 10.1007/s10722-026-02947-w

Authors: Kel Arlinghaus, Sandra Mardonovich, Oscar J. Rocha, Richard C. Moore

Institutions: Miami University, Kent State University

Language: English

Topic: Genetic diversity and population structure

Subfield: Genetics

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDGs: Life on land, Zero hunger

Open Access status: hybrid

Estimated APC paid: $2,690