Natural hybridization between species of Calceolaria with different pollination syndromes in southern Patagonia, Argentina

 Calceolaria uniflora and C. polyrhiza differ markedly in flower structure, color, and in their pollination mechanisms. Flowers of C. polyrhiza have a hidden glandular oil-secreting appendage that in the genus typically attracts bee pollinators, while in C. uniflora this is replaced by an external, white and fleshy structure that functions as food body and attracts a bird pollinator. Populations with intermediate flower morphology, presumably hybrids, were found in several sites over a large area of southern Patagonia, Argentina. The intermediate forms have so far been found always in contact or close proximity with typical populations of both presumed parent species. The distribution pattern and phenetic intermediacy in several independent flower characters strongly suggest widespread interspecific hybridization in the range of geographic overlap of the two species. The pattern of variation of intermediate forms in some sites is indicative of a hybrid swarm and possible introgression. Of particular interest is the range of intermediate structures and positions of the flower appendage, between oil gland and food tissue, that can be found in hybrid populations. The observed phenomenon raises several questions concerning the biological mechanisms generating it and its evolutionary consequences. Received May 31, 2001 Accepted September 4, 2001     

小檗属植物一新种——平坝小檗

报道了中国贵州小檗科小檗属植物一新种,即平坝小檗（Berberis pingbaensis M. T. An）新种与堆花小檗（B. aggregate Schineid.）相近似,但植物较小,果具白粉。     

An articulated titanosaur from Patagonia (Argentina): New evidence of neosauropod pedal evolution

Most titanosaur dinosaurs are represented by incomplete skeletal elements lacking articulated pes. An exceptionally preserved specimen from the Late Campanian–Early Maastrichtian strata of Patagonia (Argentina) provides new data on pedal morphology and the evolutionary trends of these huge dinosaurs. This finding is one of the few articulated titanosaur pes known in the world, and shows a phalangeal formula of 2-2-2-2-0. The first three digits possess sickle-shaped claws and the articular facets of ungual phalanges, suggesting mobility in horizontal and vertical planes. A comparative analysis of available record suggests that titanosaurs had a progressive reduction of size and number of pedal phalanges in digits III and IV during the Late Cretaceous.     

First Record of Undaria Pinnatifida (Laminariales, Phaeophyta) in Southern Patagonia, Argentina

The Japanese kelp Undaria pinnatifida was found on 7th September 2005 in Ría Deseado (Santa Cruz, Argentina). This invasive algae was registered from the lower intertidal to the upper levels of the subtidal zone. The sporophytes were fixed to slabs, gravel and rocks of variable sizes and were also present as epibionts of tunicates. The sporophytes total length ranged between 3 and 88 cm, with a mean of 28.75 cm in the intertidal and 38.3 cm in the subtidal. The density and biomass increased from the intertidal to the subtidal. The kelp population showed a higher number of small immature individuals in the intertidal than␣subtidal where the organisms were bigger and with more individual biomass. This first record of U. pinnatifida in Southern Patagonia extends its southern distribution limit in Argentina, showing progressive expansion in the southwestern Atlantic. More surveys must be conducted to understand the evolution of U. pinnatifida invasion and its impact on the native benthic community.     

A 3-year airborne pollen and fungal spores record in San Carlos de Bariloche, Patagonia, Argentina

Airborne pollen in San Carlos de Bariloche was sampled from September to March 2001–2004 with a Hirst-type volumetric spore trap placed at a height of 15 m in a city extending from the humid forests, through the mesic forests, to the steppe. The total amount of pollen recorded varied widely from year to year. The pollen index was 4,395 in the sampling period 2001/2002; 9,055 in 2002/2003 and 2,756 in 2003/2004. The main pollen period extended from October to January. In October, pollen concentration was the highest. Sixty-six pollen types were identified. Cupressaceae and Nothofagus were the major contributors. Betula, Prunus, Pinus and Populus, the most abundant ornamental taxa in the city, also contributed to the pollen record. Pollen of Maytenus and Lomatia was representative of the mesic forest, while pollen in the lower layers of the humid forest was present in trace amounts. Cupressaceae, Nothofagus and Betula prevailed during spring (September–December), and Plantago, Rumex and Poaceae during summer (December–March). The association of daily pollen concentration and meteorological variables, temperature (mean, maximum, minimum), dew point, rainfall and wind speed, was significant. Correlations showed to be negative, with the exception of that to wind speed. The total sum of fungi spores increased from 1,771 in 2001/2002; through 8,441 in 2002/2003 to 13,782 in 2003/2004. Relative concentration rose to 29%, 48% and 84% of the total number of pollen and fungal spores recorded during each sampling period.     

Reproductive biology of Colletia spinosissima (Rhamnaceae) in Argentina

 We studied the reproductive behavior of Colletia spinosissima Gmel. at six sites in two regions of Argentina during the 1998–2000 flowering seasons. Flowering takes place in winter. The flowers are homogamous, fragrant, and entomophilous. There was evidence of self-incompatibility and cross-incompatibility between nearby partners. Fruit set of open-pollinated flowers (13.3%) seemed pollen-limited, since low fecundity was consistently associated with small stigmatic pollen loads and with low numbers of successful pollen tubes, and fecundity increased with abundance of efficient pollinators. Reproductive success (percent ovules becoming viable seeds) was 3.6. It is hypothesized that homogamy was established in Colletia because in an impoverished pollination environment – such as the one likely prevailing when this lineage evolved – achieving pollen export and receipt in a single pollinator visit has selective advantages. A large stigma and an extragynoecial compitum would compensate for the homogamy-driven, increased pollen-stigma interference. Received March 8, 2001 Accepted July 19, 2001     

Comparative AFLP mapping in two hexaploid oat populations

Amplified fragment length polymorphisms (AFLPs) can be used to quickly develop linkage maps in plant species and are especially useful for crops with large genomes like oat (Avena sativa L., 2n=6x=42). High reproducibility and consistency are crucial if AFLP linkage maps are employed for comparative mapping. We mapped AFLP markers in combination with restriction fragment length polymorphism (RFLP) markers in two recombinant inbred populations of hexaploid oat in two laboratories to test the consistency of AFLP markers in a polyploid crop. Eight primer combinations produced 102 and 121 scoreable AFLP markers in the respective populations. In a population from the cross Kanota×Ogle, AFLP markers were placed onto a RFLP reference map consisting of 32 linkage groups. Nineteen linkage groups from another population from the cross Kanota×Marion were assigned to the reference map using AFLP and RFLP markers homologous to those used in the Kanota× Ogle cross. Reproducibility of AFLP assays was high in both laboratories and between laboratories. The AFLP markers were well-distributed across the genome in both populations. Many AFLP markers tended to extend the distance between adjacent RFLP markers in linkage analysis. Of the 27 polymorphic AFLPs common in both populations, 20 mapped to homologous linkage groups, 4 were unlinked in at least one population, and 3 mapped to different linkage groups in the two crosses. We believe that 1 of the 3 markers that mapped to a different linkage group in the two populations mapped to homoeologous linkage groups. The linkage map of hexaploid oat is not yet complete, and genomic rearrangements such as translocations exist among cultivars and are likely to account for the remaining two non-syntenous mapping results. AFLPs provide not only a fast and powerful tool for mapping but could be useful in characterizing genomic structural variations among germplasms in hexaploid oat. Received: 17 December 1999 / Accepted: 28 July 2000     

A new species of Grindelia (Asteraceae, Astereae) from the Meseta del Somuncura (Patagonia), Argentina

Grindelia coronensis, a new species from the Meseta del Somuncura, Prov. Río Negro, Argentina, is described and illustrated. It is similar toG. chiloensis (Cornel.) Cabrera but it is readily distinguished by its leaves which are conspicuosly differentiated into a obovate blade and a long petiole.     

Putative proteaceous elements of the Lomatites-type reinterpreted as new Berberis of the European Tertiary

 A characteristic xeromorphic foliage occurring in the European Tertiary was originally identified as a Proteaceae according to gross morphology, and compared with Grevillea L. and Lomatia L. (Grevillea kymeana Unger, Lomatites aquensis Saporta). On the basis of venation patterns and phyllotaxy, these elements are now reinterpreted as extinct species of Berberis L. (Berberidaceae): Berberis andreanszkyi spec. nov. occurring in the Upper Oligocene (Eger – Wind brickyard), and the Middle Miocene (Erdbénye) of Hungary, and Berberis kymeana (Unger) comb. nov. (syn. Lomatites aquensis Saporta) known from the Lower Miocene of Greece (Kymi) and the Oligocene of France (Aix-en-Provence, Manosque/Bois d'Asson, Cérestre, Bonieux). The associated vegetation reflects warm-temperate to subtropical subhumid climatic conditions. Extant barberries with similar foliage occur in the Himalayas and China today. Received April 3, 1999 Accepted September 25, 2000     

The correlation between development of atypical bisexual flowers and phylogeny in the Aroideae (Araceae)

 In the intermediate zone of the inflorescence of genera of Aroideae one can find flowers with male and female characteristics. Until now, two types of developmental sequences of atypical bisexual flowers (ABFs) have been recognized: the Philodendron type and the Cercestis type. In the Philodendron type, bisexual flowers generally consist of functional carpels and staminodes inserted on the same whorl. In the Cercestis type, the gynoecium and stamens are inserted on two different whorls. These different ontogenetic patterns represent two different pathways in the evolution of unisexual flowers in this subfamily. A molecular phylogenetic analysis of 33 genera of Araceae, based on the chloroplast trnL intron and trnL–F intergenic spacer sequences was carried out. We use this phylogenetic analysis and those published by French et al. (1995) and Mayo et al. (1997) to examine the distribution of the two types of ABFs in selected genera. Our results suggest that the two developmental patterns of ABFs in Aroideae sensu Mayo et al. (1997) do not correspond to two separate evolutionary lineages but rather are more or less consistent within clades. Although this new molecular phylogeny does not include all aroid genera, it corroborates in general, at the subfamily level, the molecular analysis of French et al. (1995) based on chloroplast DNA restriction site data and the analysis of Mayo et al. (1997) based on morphological and anatomical data. Received March 15, 2001 Accepted October 11, 2001     

AFLP analysis of African cassava (Manihot esculenta Crantz) germplasm resistant to the cassava mosaic disease (CMD)

Amplified fragment length polymophism was assessed in 20 land races and nine elite lines of cassava from Africa, resistant and susceptible to the cassava mosaic disease (CMD). Eleven accessions from a representative core collection from Latin America, previously studied by AFLPs, were included as a reference. AFLP data from all accessions was analyzed by both the unweighted pair group mean average (UPGMA) and multiple cluster analysis (MCA) methods of analysis. Genetic differentiation between clusters and the coefficient of genetic differentiation was also calculated. Results reveal a genetic divergence between African and Latin American accessions, although some overlap was found between them. African land races resistant to CMD, were also found to be genetically differentiated from susceptible land races and from resistant elite lines. AFLP analysis identified a considerable number of duplicates in the African accessions, suggesting a sizeable percentage of redundancy. A unique AFLP fragment, found in a relatively high frequency in African accessions, but absent in the Latin American accessions, was found to be associated with branching pattern by QTL mapping in an F1 progeny derived from African and Latin American parents. The likely source and the utility of the unique AFLP fragment in understanding the processes of genetic divergence in Africa is discussed. Received: 15 May 1999 / Accepted: 28 July 1999     

Identification of QTLs for grain yield and grain-related traits of maize (Zeamays L.) using an AFLP map, different testers, and cofactor analysis

We exploited the AFLP®¹(AFLP® is a registered trademark of Keygene, N.V.) technique to map and characterise quantitative trait loci (QTLs) for grain yield and two grain-related traits of a maize segregating population. Two maize elite inbred lines were crossed to produce 229 F₂ individuals which were genotyped with 66 RFLP and 246 AFLP marker loci. By selfing the F₂ plants 229 F₃ lines were produced and subsequently crossed to two inbred testers (T1 and T2). Each series of testcrosses was evaluated in field trials for grain yield, dry matter concentration, and test weight. The efficiency of generating AFLP markers was substantially higher relative to RFLP markers in the same population, and the speed at which they were generated showed a great potential for application in marker-assisted selection. AFLP markers covered linkage group regions left uncovered by RFLPs; in particular at telomeric regions, previously almost devoided of markers. This increase of genome coverage afforded by the inclusion of the AFLPs revealed new QTL locations for all the traits investigated and allowed us to map telomeric QTLs with higher precision. The present study has also provided an opportunity to compare simple (SIM) and composite interval mapping (CIM) for QTL analysis. Our results indicated that the method of CIM employed in this study has greater power in the detection of QTLs, and provided more precise and accurate estimates of QTL positions and effects than SIM. For all traits and both testers we detected a total of 36 QTLs, of which only two were in common between testers. This suggested that the choice of a tester for identifying QTL alleles for use in improving an inbred is critical and that the expression of QTL alleles identified may be tester-specific.     

AFLP analysis of genetic relationships in the tribe Datureae (Solanaceae)

The AFLP technique was evaluated as a tool for assessing species relationships within the tribe Datureae and genetic distances were estimated for 47 accessions of over 12 species. The phenetic trees from various analyses of the AFLP data gave very high co-phenetic correlation values, and were found to be consistent with previous trees based on the analysis of different data types, in particular ITS-1 sequences, isozymes and morphology, carried out on the same accessions. These results indicated that the AFLP technique is both an efficient and effective tool for determining genetic relationships among taxa in the Solanaceae. A new classification is proposed for the tribe Datureae, which maintains the arborescent species as a separate genus, Brugmansia, and recognises three sections within the genus Datura; Stramonium, Dutra and Ceratocaulis. D. discolor, previously placed in section Dutra, was found to be intermediate between sections Dutra and Stramonium. Received: 11 January 1999 / Accepted: 1 February 1999     

Estimating genetic diversity of Arabidopsis thaliana ecotypes with amplified fragment length polymorphisms (AFLP)

The extensive natural variation of Arabidopsis thaliana ecotypes is being increasingly exploited as a source of variants of genes which control (agronomically) important traits. We have subjected 19 different Arabidopsis thaliana ecotypes to an analysis using the anplified fragment length polymorphism (AFLP) technique in order to estimate their genetic diversity. The genetic diversity was estimated applying the method of Nei and Li (1979) and a modified version of it and using 471 informative polymorphisms. The data obtained revealed that within this small set of ecotypes a group of three ecotypes and a further single ecotype exhibit considerable genetic diversity in comparison to the others. These ecotypes clustered at positions significantly separated from the bulk of the ecotypes in the generated similarity plots. The analysis demonstrated the usefulness of the AFLP method for determinating intraspecies genetic diversity as exemplified with Arabidopsis thaliana ecotypes. Results are discussed and compared with data obtained with other methods. Received: 18 June 1999 / Accepted: 28 July 1999     

Genetic validation and characterization of RAPD markers differentiating black and red spruces: molecular certification of spruce trees and hybrids

 Picea mariana (black spruce) and P. rubens (red spruce) are closely related species which are difficult to differentiate morphologically. RAPD markers differentiating black and red spruces have been previously identified. In the present study, genetic validity of these markers was determined using samples representing range–wide provenances. Their applicability for certifying genetic identity of individual black, red trees and their hybrids from several sympatric and allopatric locations was demonstrated. These diagnostic fragments of both red and black spruce were present at a frequency of over 0.95 in allopatric provenances, but at a lower frequency in some sympatric provenances (0.43–1.00). Natural populations of red spruce exhibiting typical red spruce phenotype contained black spruce diagnostic RAPD fragments and black spruces growing in bogs with typical bog black spruce morphology, contained red spruce-specific RAPD markers. Some major RAPD markers were cloned and sequenced. The results reveal an extremely high degree of identity between the random primer and the primer binding sites on the genome. Amplification of black and red spruce genomic DNA with designed primers flanking the species-diagnostic RAPD markers indicates that most of RAPD markers used to differentiate black spruce from red spruce are not species specific since these sequences were detected in several spruce species using a more sensitive detection method. Received June 17, 2002; accepted August 5, 2002 Published online: February 4, 2003     

Hypsosteiromys (Rodentia, Hystricognathi) from the Early Miocene of Patagonia (Argentina), the only Erethizontidae with a tendency to hypsodonty

Hypsosteiromys is the only New World porcupine that shows a tendency to hypsodonty. It is recorded exclusively from the Colhuehuapian Age (Early Miocene) of central Patagonia (Argentina). In addition to the type species, a second one, Hypsosteiromys nectus(AMEGHINO, 1902), is recognized, from the southern cliff of Colhuehuapi Lake (Chubut province). It differs from the type species in the lesser development of the anterolabial and posteroflexid notches of the m1-3, shorter p4 and dp4, and more slender incisors. Dental morphology suggests that the species of Hypsosteiromys lived in more open areas than most fossil and living Erethizontidae.     

A high-density molecular map for ryegrass (Lolium perenne) using AFLP markers

AFLP markers have been successfully employed for the development of a high-density linkage map of ryegrass (Lolium perenne L.) using a progeny set of 95 plants from a testcross involving a doubled-haploid tester. This genetic map covered 930 cM in seven linkage groups and was based on 463 amplified fragment length polymorphism (AFLP) markers using 17 primer pairs, three isozymes and five EST markers. The average density of markers was approximately 1 per 2.0 cM. However, strong clustering of AFLP markers was observed at putative centromeric regions. Around these regions, 272 markers covered about 137 cM whereas the remaining 199 markers covered approximately 793 cM. Most genetic distances between consecutive pairs of markers were smaller than 20 cM except for five gaps on groups A, C, D, F and G. A skeletal map with a uniform distribution of markers can be extracted from this high-density map, and can be applied to detect and map QTLs. We report here the application of AFLP markers to genome mapping, in Lolium as a prelude to quantitative trait locus (QTL) identification for diverse agronomic traits in ryegrass and for marker-assisted plant breeding. Received: 4 November 1998 / Accepted:15 March 1999     

Late Miocene continental biota in Northeastern Patagonia (Península Valdés, Chubut, Argentina)

A new vertebrate faunal assemblage was recently discovered from the uppermost part of the late Miocene Puerto Madryn Formation. These deposits crop out along the southwestern coast of the Península Valdés area near Punta Delgada (Chubut Province, Argentina). The exhumed vertebrate fauna includes a range of fish, bird and mammal taxa, of which the latter are most varied and abundant. The new findings represent the first record of continental fossil vertebrates in the Puerto Madryn Formation and this is the first assemblage of late Miocene continental vertebrates recorded to the south of Río Negro Province. It also includes the southernmost record of Hydrochoeridae rodents, Dendrocygninae birds and Loricariidae fishes. The mammals suggest that the fossil-bearing sediments are Huayquerian in age. The climate during the accumulation of late Miocene deposits in this region is inferred to have been warmer and seasonally drier than that of today.     

Detecting the influence of ornamental Berberis thunbergii var. atropurpurea in invasive populations of Berberis thunbergii (Berberidaceae) using AFLP1

Japanese barberry (Berberis thunbergii DC.) is a widespread invasive plant that remains an important landscape shrub represented by ornamental, purple-leaved forms of the botanical variety atropurpurea. These forms differ greatly in appearance from feral plants, bringing into question whether they contribute to invasive populations or whether the invasions represent self-sustaining populations derived from the initial introduction of the species in the late 19th century. In this study we used amplified fragment length polymorphism (AFLP) markers to determine whether genetic contributions from B. t. var. atropurpurea are found within naturalized Japanese barberry populations in southern New England. Bayesian clustering of AFLP genotypes and principal coordinate analysis distinguished B. t. var. atropurpurea genotypes from 85 plants representing five invasive populations. While a single feral plant resembled B. t. var. atropurpurea phenotypically and fell within the same genetic cluster, all other naturalized plants sampled were genetically distinct from the purple-leaved genotypes. Seven plants from two different sites possessed morphology consistent with Berberis vulgaris (common barberry) or B. ×ottawensis (B. thunbergii × B. vulgaris). Genetic analysis placed these plants in two clusters separate from B. thunbergii. Although the Bayesian analysis indicated some introgression of B. t. var. atropurpurea and B. vulgaris, these genotypes have had limited influence on extant feral populations of B. thunbergii.