Center Of Origin Research Articles

Phylogeography, genetic diversity and population structure in a Patagonian endemic plant.

Phylogeographical patterns provide valuable insight into the historical processes underlying diversification, and may provide a better understanding of biodiversity, dispersal modes, diversification times, extinctions, refuge areas and other species-/population-level processes. Here, we examine the genetic structure of Oxalis laciniata, a representative of Oxalis, which is an important emerging model in evolutionary biology and phylogenetic studies. We analyse genetic correlation, haplotype diversity and genetic structure. In this study, cpDNA reveals the presence of 16 haplotypes, connected in tree networks. Genetic diversity is high and polymorphism is low among populations based on ISSR markers. Both clustering and analysis of the structure of the population indicate two different groups. Distribution modelling predicts two potential distribution areas. Our main conclusions are: (i) The phylogeographical pattern demonstrates non-random organization of genetic variability since two distinct groups can be distinguished; (ii) two refugia are proposed: one is situated in the SE, holding the most ancestral haplotypes; and the second one is situated in the SW; (iii) we propose an in situ diversification hypothesis for the populations located in the steppe; (iv) the centre of diversification coincides with the centre of the distribution; (v) distribution modelling shows a strong correspondence with the distribution of the species but it also suggests the possibility of occurrence in the Central Andes.

North Andean origin and diversification of the largest ithomiine butterfly genus

The Neotropics harbour the most diverse flora and fauna on Earth. The Andes are a major centre of diversification and source of diversity for adjacent areas in plants and vertebrates, but studies on insects remain scarce, even though they constitute the largest fraction of terrestrial biodiversity. Here, we combine molecular and morphological characters to generate a dated phylogeny of the butterfly genus Pteronymia (Nymphalidae: Danainae), which we use to infer spatial, elevational and temporal diversification patterns. We first propose six taxonomic changes that raise the generic species total to 53, making Pteronymia the most diverse genus of the tribe Ithomiini. Our biogeographic reconstruction shows that Pteronymia originated in the Northern Andes, where it diversified extensively. Some lineages colonized lowlands and adjacent montane areas, but diversification in those areas remained scarce. The recent colonization of lowland areas was reflected by an increase in the rate of evolution of species’ elevational ranges towards present. By contrast, speciation rate decelerated with time, with no extinction. The geological history of the Andes and adjacent regions have likely contributed to Pteronymia diversification by providing compartmentalized habitats and an array of biotic and abiotic conditions, and by limiting dispersal between some areas while promoting interchange across others.

Contribution to Globularia phylogeny based on nuclear ribosomal spacer and two chloroplast DNA regions

Background and Purpose: Molecular approach has a major impact on phylogenetic studies of plants, considering that it gives useful information about evolutionary events and relations on all taxonomic levels. The sequence data of the nuclear ITS and of two chloroplast regions, trnL-trnF spacer and rbcL gene, obtained from thirteen Globularia L. taxa, including five Anatolian endemics, representing six sections altogether, were analyzed in order to determine the relations between the European and the Anatolian species and get a better insight into the phylogeny of several closely related Globularia taxa. Materials and Methods: Total cellular DNA was extracted from fresh or frozen leaf tissue of thirteen Globularia samples. The ITS regions of nuclear DNA and two chloroplast DNA regions were amplified and sequenced. Obtained nuclear and combined plastid data matrices were subjected to Maximum Parsimony analyses. Results and Conclusions: Molecular data that were obtained in this study indicate the existence of separate centers of diversification for the European and the Anatolian Globularia. The results provide support for relationships among the studied Anatolian endemic species and indications for a redefinition of affinities of some of the European species. The results presented herein are discussed along with available morphological, karyological, phytogeographical and molecular data. Keywords: Globularia, ITS, trnL-trnF, rbcL, Maximum Parsimony, Quaternary

A new osteichthyan from the late Silurian of Yunnan, China.

Our understanding of early gnathostome evolution has been hampered by a generally scant fossil record beyond the Devonian. Recent discoveries from the late Silurian Xiaoxiang Fauna of Yunnan, China, have yielded significant new information, including the earliest articulated osteichthyan fossils from the Ludlow-aged Kuanti Formation. Here we describe the partial postcranium of a new primitive bony fish from the Kuanti Formation that represents the second known taxon of pre-Devonian osteichthyan revealing articulated remains. The new form, Sparalepis tingi gen. et sp. nov., displays similarities with Guiyu and Psarolepis, including a spine-bearing pectoral girdle and a placoderm-like dermal pelvic girdle, a structure only recently identified in early osteichthyans. The squamation with particularly thick rhombic scales shares an overall morphological similarity to that of Psarolepis. However, the anterior flank scales of Sparalepis possess an unusual interlocking system of ventral bulges embraced by dorsal concavities on the outer surfaces. A phylogenetic analysis resolves Sparalepis within a previously recovered cluster of stem-sarcopterygians including Guiyu, Psarolepis and Achoania. The high diversity of osteichthyans from the Ludlow of Yunnan strongly contrasts with other Silurian vertebrate assemblages, suggesting that the South China block may have been an early center of diversification for early gnathostomes, well before the advent of the Devonian “Age of Fishes”.

Molecular systematics and phylogeography of the genus Echinops (Compositae, Cardueae–Echinopsinae): focus on the Iranian centre of diversification

A molecular phylogeny of the genus Echinops (Asteraceae, Cardueae) based on plastid and nuclear markers is presented. The study focuses on the Iranian representatives of the genus, which constitute a larger part of Echinops. The Bayesian cpDNA tree resulted in a large polytomy. However, the Bayesian ITS tree displayed a well-resolved topology more compatible with the taxonomic treatment generally accepted in Echinops. An ITS network illustrates a close relationship of haplotypes. Mapping diagnostic morphological characters onto the ITS tree revealed a high level of homoplasy among the studied taxa. Except for the life cycle, all other morphological characters evolved many times among the clades and most of them appeared to be of low taxonomical value. Based on the nucleotide polymorphism and haplotypes, the taxonomic status of some taxa was evaluated. The independent status of E. sect. Phaeochaete was confirmed by molecular analyses and morphological characters. The paraphyletic nature of E. sect. Echinops was confirmed. As for the molecular dating, our results suggest that the genus evolved in the early Miocene but the main speciation events took place in the Pliocene-Pleistocene. The biogeographic results do not support any specific ancestral area for Echinops, yet the model states that its current diversity originated in the Irano-Turanian Region and the Eastern Mediterranean region. Some taxonomic changes are suggested, in the synonymy and placement of some taxa.

Ten years of progress in the study of Hadena-Caryophyllaceae nursery pollination. A review in light of new Mediterranean data

Nursery pollination interactions are widespread between Caryophyllaceae species and the pollinating-seed predator Hadena moths (Noctuidae). A previous revision of this system was based mainly on widely distributed species in the north and center of Europe. However, there was no information from the Mediterranean region, one of the global diversification centers of both taxa. The aim of this work is to review the progress on the knowledge of this nursery pollination system since the first revision, providing unpublished data of Caryophyllaceae-Hadena associations from Spain. Furthermore, we conduct a preliminary network analysis to illustrate the advantages of this approach to explore nursery pollination systems.In the last 10 years, most of studies have focused on selective forces exerted by Hadena on the plant reproductive traits through pollination and predation. Hadena moths are selectively attracted by flower scents, flower sizes and number of flowers per plant are also crucial for attraction of the moths. Caryophyllaceae species may have developed some phenological, chemical, morphogical and physiological adaptations to avoid overexploitation by larvae. The evolution of sexual dimorphism in Caryophyllaceae may be a consequence of mutualistic and antagonistic interactions. Other pollinators as well as an anther smut fungus and larval parasitoids are important selective agents that can shift this interaction between mutualism and parasitism. Whereas most studies highlighted the parasitic nature of the Hadena-Caryophyllaceae interaction, we need further analyses on the pollinator effectiveness of Hadena and on the spatio-temporal variation of the interaction outcome. Based on our field surveys and bibliographic records we found evidence of nursery pollination between 22 noctuid species (mostly Hadena) and 70 Caryophyllaceae species from 11 genera (mostly Silene and Dianthus). From these interactions, 26 were new for the Iberian Peninsula and 18 were not described before. Results of our preliminary network analysis suggest that these interactions are constrained by phylogenetic, geographical and ecological filters.

Effect of overhead irrigation on corn yield and quality under shallow water table conditions.

Corn is a moisture sensitive crop and drought conditions during critical growth stages affect kernel yield and quality. The objective of this field research was to determine the impact of water contribution from shallow water table under overhead irrigation and no irrigation treatments on corn yield, in a fine sandy loam soil in Southern Manitoba. The study was conducted at two different sites (Canada Manitoba Crop Diversification Centre (CMCDC), and Hespler Farms). Compared to no irrigation treatment, the overhead-irrigated plots had a 16% (p = 0.021) and 9% (p = 0.025) significantly higher yield at CMCDC, and Hespler sites, respectively. The kernel quality, based on kernels passing through 14/64-mesh size, in overhead-irrigated plots was found to be significantly better in overhead-irrigated plots at CMCDC (p = 0.011) and Hespler (p = 0.003) sites compared to the non-irrigated treatment. The increased unsaturated hydraulic conductivity due to increased water content of the soil beneath the root zone in the irrigated treatment led to an increased upward migration of water from the shallow water table compared to the upward migration in the non-irrigated treatment. In the irrigated treatment, the irrigation water quality was better than the quality of the water supplied from the water table because groundwater had high concentration of nitrate (55 ppm). However, in the non-irrigated treatment, the precipitation alone was not sufficient to dilute the poor quality water from the water table leading to lower yield and poor kernel quality.

Diversification in arid mountains: biogeography and cryptic diversity of Pristurus rupestris rupestris in Arabia

AbstractAimTo understand the patterns of genetic, geographical and morphological diversification in the Arabian gecko subspecies Pristurus rupestris rupestris, and to discuss the various processes that generate and shape diversity in arid mountain ranges.LocationHajar Mountains, south‐eastern Arabian Peninsula.MethodsWe sampled 466 individuals across the entire range of P. r. rupestris in the Hajar Mountains and sequenced one mitochondrial gene for all the samples, and one extra mitochondrial and four nuclear genes for a subset of 75 specimens. A total of 155 individuals were characterized morphologically. Multilocus coalescent‐based methods were used for species delimitation, for phylogenetic inference of species trees and to investigate the diversification dynamics. Multivariate statistics were used to analyse morphological data.ResultsOur molecular methods revealed 14 candidate species hidden within the subspecies P. r. rupestris. Diversification started c. 15 Ma, but most of the lineages have evolved in the last 7 Ma of the mountains’ orogeny, producing a mosaic of allopatric taxa. Secondary interchange has occurred between high and low elevation lineages, and along the mountain chain between unrelated lineages formerly separated by mountain blocks. Morphological variation between the 14 candidate species is slight, but a high elevation robust morphotype is identified.Main conclusionsOur results support the notion that mountain ranges constitute important centres of diversification in arid regions, and also act as ‘species pumps’ into surrounding areas. We also demonstrate that arid mountains may constitute important reservoirs of cryptic diversity, even in common and widespread species. This, and previous evidence, suggest that the Hajar Mountains are a biological hotspot and an important reservoir of diversity. We therefore suggest that these mountains should be a priority focal point for conservation in Arabia.

New taxa of Berberis (Berberidaceae) with greenish flowers from a biodiversity hotspot in Sichuan Province, China

A new species, Berberis viridiflora X. H. Li, and a new variety, Berberis sanguinea Franch. var. viridisepala X. H. Li, L. C. Zhang & W. H. Li are described and illustrated from Baoxing County, a biodiversity hotspot located on the eastern edge of Hengduan Mountains in Sichuan Province, Southwest China. Both new taxa resemble B. sanguinea Franch. var. sanguinea, but B. viridiflora differs by the greenish flowers, and the petals being truncate, obtuse, or undulate at apex; while B. sanguinea var. viridisepala differs by the greenish or yellowish green flowers. Morphological features of the pollen grains of B. sanguinea and the two new taxa are revealed by scanning electron microscope. B. sanguinea var. sanguinea displays obvious similarities with a sympatric congener, Berberis multiovula T. S. Ying in the morphology of flowers, stems and leaves, especially its ovule number varies greatly from 2 to 9, thus, B. multiovula characterized by the 5-ovuled ovary is reduced to a synonymy of B. sanguinea var. sanguinea. On the basis of field surveys and study of herbarium specimens, a total of 16 species and varieties of Berberis are recorded from Baoxing County, and a key is provided. Among the 16 taxa, most phenotypic variations in Chinese Berberis can be displayed, including the habit of plants, most morphological variations of stems, branches and leaves, all types of inflorescences, all color types of flowers, and nearly all types of the shape and color of fruits. Baoxing County and its adjacent Sichuan Giant Panda Sanctuaries possibly constitute an active diversification center of Berberis in eastern Hengduan Mountains of China.

Panmixia and dispersal from the Mediterranean Basin to Macaronesian Islands of a macrolichen species

The Mediterranean region, comprising the Mediterranean Basin and the Macaronesian Islands, represents a center of diversification for many organisms. The genetic structure and connectivity of mainland and island microbial populations has been poorly explored, in particular in the case of symbiotic fungi. Here we investigated genetic diversity and spatial structure of the obligate outcrossing lichen-forming fungus Parmelina carporrhizans in the Mediterranean region. Using eight microsatellite and mating-type markers we showed that fungal populations are highly diverse but lack spatial structure. This is likely due to high connectivity and long distance dispersal of fungal spores. Consistent with low levels of linkage disequilibrium and lack of clonality, we detected both mating-type idiomorphs in all populations. Furthermore we showed that the Macaronesian Islands are the result of colonization from the Mediterranean Basin. The unidirectional gene flow, though, seemed not to be sufficient to counterbalance the effects of drift, resulting in comparatively allelic poor peripheral populations. Our study is the first to shed light on the high connectivity and lack of population structure in natural populations of a strictly sexual lichen fungus. Our data further support the view of the Macaronesian Islands as the end of the colonization road for this symbiotic ascomycete.

Phylogeny and evolution of shallow‐water squat lobsters (Decapoda, Galatheoidea) from the Indo‐Pacific

Squat lobsters have a worldwide distribution and are highly visible crustaceans living in a broad range of habitats. In this study, partial sequences of two mitochondrial DNA genes (16S rRNA and COI) and a nuclear gene (H3) were obtained for all but one of the known species of the shallow‐water genera Sadayoshia (Munididae) and Lauriea, Macrothea and Triodonthea (Galatheidae). Lauriea siagiani appeared to be phylogenetically closer to Triodonthea and Macrothea than to other Lauriea species, suggesting the need for taxonomic re‐evaluation of these taxa. All species of Sadayoshia formed a monophyletic group that would have diverged during the Paleogene (around 50 Mya). Our results support the hypothesis that the late Paleogene–Neogene transition was a period of rapid diversification for shallow‐water species of both Galatheidae and Munididae in the Indo‐Pacific region. This is probably related to high tectonic activity among the Eurasian, Philippine Sea, Indo‐Australian and Pacific plates and corresponding changes in distribution of habitats and ocean currents during the late Paleogene. Finally, the tropical south‐west Pacific province is identified as a major diversification centre for shallow‐water squat lobsters, from where species dispersed to other Pacific and Indian Ocean regions.

Beaucarnea olsonii (Ruscaceae), a new species of ponytail palm from southwestern Puebla, Mexico

Beaucarnea olsonii is described and illustrated from tropical deciduous forests of SW Puebla, Mexico. The new species can be distinguished from other Beaucarnea species by its massively swollen base that abruptly tapers into slender branches, by its conspicuously long stigma, and by its pedicel articulation that occurs at 2/3 of the length of the pedicel below the flower. With this new addition, the total number of endemic species of Beaucarnea for Mexico increases to 10, making this country the greatest center of diversification and endemism for the genus. We also provide a distribution map and a conservation status recommendation for the new species, as well as a key to the Beaucarnea species of southern central Mexico.

Extracción y morfología del embrión de Bursera bipinnata (Burseraceae)

Antecedentes y Objetivos: El entendimiento de la biología reproductiva de las plantas, desde la formación de la semilla hasta su establecimiento, permite el desarrollo de diferentes estrategias de conservación. En el género Bursera, cuyo principal centro de diversificación es México, la diáspora es un pireno formado por un endocarpo fuertemente lignificado que encierra a la semilla. Las características anatómicas del pireno y la partenocarpia son los principales factores que han obstaculizado el estudio de la embriogénesis y el desarrollo de técnicas de propagación. En este trabajo se describe la morfología del embrión de Bursera bipinnata extraído mediante una técnica que no altera la estructura o la composición química de los tejidos.Métodos: Durante el inicio de la etapa de dispersión 2014, se colectaron frutos inmaduros y pirenos con pseudoarilo expuesto, los frutos inmaduros se fijaron en FAA. Se utilizó un micromotor con pieza de mano de baja velocidad. En los frutos inmaduros se utilizó un fresón cónico para desgastar las valvas del fruto. Para abrir los pirenos se utilizó un disco de diamante. Una vez abierto el endocarpo, los embriones se extrajeron y se fijaron.Resultados clave: El patrón de desarrollo coincide con otras especies modelo de angiospermas. En los frutos inmaduros se encontraron las fases globular, acorazonada, torpedo y cotiledonar, ésta última en etapas iniciales. En la fase de torpedo los cotiledones se ramifican en tres lóbulos y se empalman, a medida que crecen se pliegan sobre si mismos encerrando el eje embrionario; sin embargo, el meristemo radicular siempre queda expuesto. El embrión se clasificó como embrión axial foliado contortuplicado.Conclusiones: La técnica de extracción es rápida, de bajo costo y no invasiva para los tejidos, teniendo un uso potencial en el análisis detallado de la embriogénesis del género Bursera, el cultivo de tejidos y la conservación ex situ.

The plant endemism in the Maritime and Ligurian Alps

The Maritime and Ligurian Alps have a flora characterised by a very high number of endemic species in relation to their small geographical extension. This area is considered one of the most important centres of diversification of the Alps and a Mediterranean hotspot of biodiversity. In the last years many studies were performed in order to describe the distribution and phylogeographical patterns of endemism. Despite these studies, Maritime and Ligurian Alps still lack in a broad view about the evolution of endemisms in this area. In this review, we examine the knowledge about the distribution patterns of endemic plant species living in the Maritime and Ligurian Alps in order to identify the evolutionary and biogeographical mechanisms operating on them.

Leapfrogging into new territory: How Mascarene ridged frogs diversified across Africa and Madagascar to maintain their ecological niche

The Mascarene ridged frog, Ptychadena mascareniensis, is a species complex that includes numerous lineages occurring mostly in humid savannas and open forests of mainland Africa, Madagascar, the Seychelles, and the Mascarene Islands. Sampling across this broad distribution presents an opportunity to examine the genetic differentiation within this complex and to investigate how the evolution of bioclimatic niches may have shaped current biogeographic patterns. Using model-based phylogenetic methods and molecular-clock dating, we constructed a time-calibrated molecular phylogenetic hypothesis for the group based on mitochondrial 16S rRNA and cytochrome b (cytb) genes and the nuclear RAG1 gene from 173 individuals. Haplotype networks were reconstructed and species boundaries were investigated using three species-delimitation approaches: Bayesian generalized mixed Yule-coalescent model (bGMYC), the Poisson Tree Process model (PTP) and a cluster algorithm (SpeciesIdentifier). Estimates of similarity in bioclimatic niche were calculated from species-distribution models (maxent) and multivariate statistics (Principal Component Analysis, Discriminant Function Analysis). Ancestral-area reconstructions were performed on the phylogeny using probabilistic approaches implemented in BioGeoBEARS. We detected high levels of genetic differentiation yielding ten distinct lineages or operational taxonomic units, and Central Africa was found to be a diversity hotspot for these frogs. Most speciation events took place throughout the Miocene, including “out-of-Africa” overseas dispersal events to Madagascar in the East and to São Tomé in the West. Bioclimatic niche was remarkably well conserved, with most species tolerating similar temperature and rainfall conditions common to the Central African region. The P. mascareniensis complex provides insights into how bioclimatic niche shaped the current biogeographic patterns with niche conservatism being exhibited by the Central African radiation and niche divergence shaping populations in West Africa and Madagascar. Central Africa, including the Albertine Rift region, has been an important center of diversification for this species complex.

Glaciations, gradients, and geography: multiple drivers of diversification of bush frogs in the Western Ghats Escarpment.

The historical processes underlying high diversity in tropical biodiversity hotspots like the Western Ghats of Peninsular India remain poorly understood. We sampled bush frogs on 13 massifs across the Western Ghats Escarpment and examined the relative influence of Quaternary glaciations, ecological gradients and geological processes on the spatial patterns of lineage and clade diversification. The results reveal a large in situ radiation (more than 60 lineages), exhibiting geographical structure and clade-level endemism, with two deeply divergent sister clades, North and South, highlighting the biogeographic significance of an ancient valley, the Palghat Gap. A majority of the bush frog sister lineages were isolated on adjacent massifs, and signatures of range stasis provide support for the dominance of geological processes in allopatric speciation. In situ diversification events within the montane zones (more than 1800 m) of the two highest massifs suggest a role for climate-mediated forest-grassland persistence. Independent transitions along elevational gradients among sub-clades during the Miocene point to diversification along the elevational gradient. The study highlights the evolutionary significance of massifs in the Western Ghats with the high elevations acting as centres of lineage diversification and the low- and mid-elevations of the southern regions, with deeply divergent lineages, serving as museums.

Isoflavone Content in Subterranean Clover Germplasm from Sardinia.

Subterranean clover (Trifoliumsubterraneum) is an important pasture legume, and Sardinia is known as a major centre of diversification of this species. As other legumes, this clover produces biologically active flavonoids including the subclass of isoflavones that are natural phytoestrogens with positive health effects. Present sources of isoflavones for medical/nutraceutical treatments are red clover (Trifoliumpratense) and soybean (Glycinemax). This study assessed the content and composition of flavonoids in 14 subterranean clover genotypes from Sardinia, grown ex-situ in comparison with two red clover ecotypes, to acquire information on the potential of the species as an alternative source of isoflavones for possible exploitation. Twenty compounds were tentatively identified across the two clovers after HPLC and LC/ESI-MS analyses, including clovamide, four flavonols, and 15 isoflavones. Most compounds were present as glucosides or glucosyl malonates. Subterranean clover extracts mainly comprised of derivatives of the isoflavones genistein, biochanin A, and formononetin. Compared to red clover, subterranean clover had higher content of total isoflavones and lower concentration of total flavonols. The isoflavone concentration in subterranean clover was higher than literature data for soybean or red clover. The existing genotypic variation warrants the possibility of selecting varieties with high isoflavone concentration for nutraceutical or pharmaceutical purposes.

Timing the evolutionary history of tent-making bats, genus Uroderma (Phyllostomidae): A biogeographic context

Geological events, such as the rising of the Andes and the completion of the Isthmus of Panama (linking North and South America) have induced the end or the beginning of geographical barriers, as well as the establishment of environmental conditions that can limit or extend species’ distribution. These events seem to be related with the diversification of the tent-making bats, genus Uroderma (Chiroptera: Phyllostomidae). In the present study, different methodological approaches were applied to reconstruct the evolutionary history of Uroderma, through the estimation of a diversification time-frame, dispersal routes, and to determine the origin of its hybrid zone in Central America. We analyzed sequences from the mitochondrial gene Cytochrome b (Cyt-b). Phylogenetic relationships between species were estimated using maximum parsimony and Bayesian inference approaches, we reconstructed the biogeographic history of the genus, divergence times for the splitting events were determined, and demographic history of species involved in the hybrid zone (U. convexum and U. davisi) was estimated. The Central Andes was identified as a center of diversification for Uroderma during the Late Miocene (5.8–3.7 Mya), and Central America for the most recent common ancestor of U. convexum and U. bakeri+U. davisi, which migrated though a stepping stone model before the completion of the Isthmus of Panama (3.8 Mya; 95%, Higuest Posterior Distribution [HPD] 4.6–2.9 Mya); Central America was recovered as the distribution of MRCA of U. bakeri and U. davisi, and its split dated to the late Pliocene – Quaternary (2.8 Mya, 4–1.4 Mya). The diversification of Uroderma is a series of recent events that involved dispersal episodes across extreme barriers (Panama Canal and the highlands of the northern Andes), with potential for population expansion and retreats, explaining the current distribution of the species.

Sex expression and floral diversity in Jatropha curcas: a population study in its center of origin.

Sex expression and floral morphology studies are central to understand breeding behavior and to define the productive potential of plant genotypes. In particular, the new bioenergy crop Jatropha curcas L. has been classified as a monoecious species. Nonetheless, there is no information about its reproductive diversity in the Mesoamerican region, which is considered its center of origin and diversification. Thus, we determined sex expression and floral morphology in J. curcas populations from southern Mexico and Guatemala. Our results showed that most of J. curcas specimens had typical inflorescences with separate sexes (monoecious); meanwhile, the rest were atypical (gynoecious, androecious, andromonoecious, androgynomonoecious). The most important variables to group these populations, based on a discriminant analysis, were: male flower diameter, female petal length and male nectary length. From southern Mexico “Guerrero” was the most diverse population, and “Centro” had the highest variability among the populations from Chiapas. A cluster analysis showed that the accessions from southern Mexico were grouped without showing any correlation with the geographical origin, while those accessions with atypical sexuality were grouped together. To answer the question of how informative are floral morphological traits compared to molecular markers, we perform a Mantel correlation test between the distance matrix generated in this study and the genetic distance matrix (AFLP) previously reported for the same accessions. We found significant correlation between data at the level of accessions. Our results contribute to design genetic improvement programs by using sexually and morphologically contrasting plants from the center of origin.

Genetic Characterization of Turkish Snake Melon (Cucumis melo L. subsp. melo flexuosus Group) Accessions Revealed by SSR Markers.

Snake melon is an important cucurbit crop especially in the Southeastern and the Mediterranean region of Turkey. It is consumed as fresh or pickled. The production is mainly done with the local landraces in the country. Turkey is one of the secondary diversification centers of melon and possesses valuable genetic resources which have different morphological characteristics in case of snake melon. Genetic diversity of snake melon genotypes collected from different regions of Turkey and reference genotypes obtained from World Melon Gene Bank in Avignon-France was examined using 13 simple sequence repeat (SSR) markers. A total of 69 alleles were detected, with an average of 5.31 alleles per locus. The polymorphism information content of SSR markers ranged from 0.19 to 0.57 (average 0.38). Based on cluster analysis, two major groups were defined. The first major group included only one accession (61), while the rest of all accessions grouped in the second major group and separated into different sub-clusters. Based on SSR markers, cluster analysis indicated that considerably high genetic variability exists among the examined accessions; however, Turkish snake melon accessions were grouped together with the reference snake melon accessions.