Repeated domestication of melon (Cucumis melo) in Africa and Asia and a new close relative from India

Abstract

Premise of the StudyThe domestication history of melon is still unclear. An African or Asian origin has been suggested, but its closest wild relative was recently revealed to be an Australian species. The complicated taxonomic history of melon has resulted in additional confusion, with a high number of misidentified germplasm collections currently used by breeders and in genomics research.MethodsUsing seven DNA regions sequenced for 90% of the genus and the major cultivar groups, we sort out described names and infer evolutionary origins and domestication centers.Key ResultsWe found that modern melon cultivars go back to two lineages, which diverged ca. 2 million years ago. One is restricted to Asia (Cucumis melo subsp. melo), and the second, here described as C. melo subsp. meloides, is restricted to Africa. The Asian lineage has given rise to the widely commercialized cultivar groups and their market types, while the African lineage gave rise to cultivars still grown in the Sudanian region. We show that C. trigonus, an overlooked perennial and drought‐tolerant species from India is among the closest living relatives of C. melo.ConclusionsMelon was domesticated at least twice: in Africa and Asia. The African lineage and the Indian C. trigonus are exciting new resources for breeding of melons tolerant to climate change.

Comparative Metabolomics and Molecular Phylogenetics of Melon (Cucumis melo, Cucurbitaceae) Biodiversity

“…The Duda'im and Momordica accessions that were included in our study are allied with subsp. melo but form an outlying cluster within that subspecies, as recently suggested [8,17,19]. However, with respect to the comparison of phylogenetic and the combined metabolomics-based classification (Figures 2 and 3), the agrestis subspecies does not behave as a single Group.…”

“…Clade (as in Figure 2) Based on 23,931 genetic polymorphisms, the 44 accessions could be classified into two well-defined clusters (referred to as I and II) clearly distinguishing between the subspecies agrestis and melo ( Figure 2). A more distant accession designated Qishu Meshullash (QME), either Cucumis trigonus or C. colossus, both of which have been included in agrestis by Endl et al [19], was included in the GBS analysis as an outlier. The smaller cluster I consists entirely of the subsp.…”

“…and melo ( Figure 2). A more distant accession designated Qishu Meshullash (QME), either Cucumis trigonus or C. colossus, both of which have been included in agrestis by Endl et al [19], was included in the GBS analysis as an outlier. The smaller cluster I consists entirely of the subsp.…”

Origin and domestication of Cucurbitaceae crops: insights from phylogenies, genomics and archaeology

“…The maximum likelihood (ML) tree was inferred from six plastid and one nuclear locus from Endl et al . (), with ML support above branches and Bayesian poster probabilities below branches. Blue‐coloured taxa indicate likely progenitor taxa, red‐coloured taxa indicate domesticated taxa.…”

“…However, it is DNA sequencing of old and new material (usually leaf tissues), informed by meta‐data from herbarium specimens, that has yielded the most surprising insights. Such work has by now identified closest relatives, ancestral areas and divergence times of pumpkin, zucchini, squashes, bottle gourd, bitter gourd, chayote, honey melon, watermelon, cucumber, bryonies, and sponge gourds (Sanjur et al ., ; Erickson et al ., ; Clarke et al ., ; Renner et al ., ; Volz & Renner, ; Schaefer & Renner, ; Sebastian et al ., , ; Telford et al ., ,b; Filipowicz et al ., ; Chomicki & Renner, ; Endl et al ., ).…”