Analysis of the biodiversity of hawthorn (Crataegus spp.) from the morphological,molecular, and ethnobotanical approaches,and implications for genetic resource conservation in scenery of increasing cultivation: the case of Mexico

One hundred and forty Mexican hawthorn (Crataegus spp.) accessions from six regions are preserved at the BGT-UACH germplasm bank (Mexico), comprising the most comprehensive living collection of Mexican hawthorns with different degrees of human management. The objective of this study was to assess the biodiversity of this valuable collection from morphological, molecular (microsatellite), and ethnobotanical viewpoints in order to delineate the most adequate strategy for the conservation of the native hawthorn germplasm in the present scenario of incipient establishment of commercial hawthorn plantations, which is likely to increase. Molecular characterisation revealed that the biodiversity was chiefly (90%) placed within the regions. Morphological characterisation indicated that the group from Chiapas was the most different germplasm pool compared with the other five. This was confirmed by molecular analysis, because in spite of the lack of a phylogeographical pattern, two germplasm pools were detected: one composed mainly by accessions from Chiapas and the other mainly by accessions from the other regions. The only clear differences among the regions in the ethnobotanical study were those derived from putting hawthorns into commercial cultivation, which occurred in just one region in the centre of the country (Mexico–Puebla–Tlaxcala). As a consequence, an ex situ conservation programme is necessary for those regions shifting patterns of cultivation from traditional to commercial, regardless of whether other on-farm programmes are also implemented. The germplasm collections within each region must be exhaustive due to their high genetic diversity.