Recombination around the <Emphasis Type="Italic">P</Emphasis> locus for long glume phenotype in experimental introgression lines of <Emphasis Type="Italic">Triticum aestivum</Emphasis> – <Emphasis Type="Italic">Triticum polonicum</Emphasis>

A set of experimental introgression lines of Triticum aestivum L. cv. Novosibirskaya 67 (N67)—Triticum polonicum L. line IC 12196 was developed using a small-scale bulk breeding method. The linkage map in chromosome 7A was constructed using F₂ hybrids of N67/IC12196 and 34 microsatellite markers. The P gene was flanked by the centromeric markers, Xgwm890 (18.6 cM) and Xbarc108 (20.0 cM) on the long arm of chromosome 7A. Among 124 introgression lines, 118 lines were hexaploid (2n = 6x = 42), and 6 were tetraploid (2n = 4x = 28). Among hexaploid accessions, 68 were long-glumed, whereas 50 were normal-glumed. Thirty-four polymorphic microsatellite markers were scored for either the N67 alleles or IC 12196 alleles in 124 introgression lines derived from N67/IC 12196. The UPGMA dendrogram showed five clusters; Cluster 1 mainly contained hexaploid introgression lines with long glumes. Although the alleles around the P locus were recombined with IC1296 alleles, the distal end of the chromosome contained N67 alleles. Cluster 2 mainly contained normal glumed, hexaploid introgression lines. These predominantly had the N67 alleles on the long arm of chromosome 7A and the short arm proximal to the centromere. Cluster 3 contained long-glumed, hexaploid wheat lines with relatively high level of recombination. Cluster 4 contained non-parental alleles. Cluster 5 contained the group of tetraploid wheat lines. These tetraploid lines have IC12196 alleles on both arms of chromosome 7A. The frequency spectrum of parental alleles and chromosomal blocks among introgression lines suggested that T. aestivum – T. polonicum hybridization can rapidly give rise to a new landrace due to selective introgression of the P gene.     

Differentiation among Maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) Landraces from the Tarasca Mountain Chain,Michoacan, Mexico and the <Emphasis Type="Italic">Chalqueño</Emphasis> Complex

The classification of Mexican maize (Zea mays L.) begun since the early 20th century, it was consolidated during the middle of this century, but recent additions and rearrangements have been performed by several authors employing new methods of analysis and collections from diverse origin; nevertheless, maize from the State of Michoacan, Mexico has received little attention in regard to its systematic classification. Maize populations from the Tarasca Mountain Chain in Michoacan are commonly considered in literature, as belonging to the Chalqueño race; however, closer observations indicate that significant differences do exist, suggesting the necessity of performing an in-depth study on this respect. Thirty nine native maize populations from the Tarasca Mountain Chain region were evaluated along with 19 typical populations of the Chalqueño, Celaya and Conico races coming from the States of Mexico, Puebla, Hidalgo, Querétaro and Oaxaca. Populations were evaluated in Aranza, Michoacan and Montecillo, Mexico State. Seventeen morphological characters were scored and analyzed by one-way analyses of variance and multivariate techniques. Populations were also genetically analyzed through 17 isozyme loci. Native populations had some alleles not found either in the Chalqueño, Celaya or Conico races, and possess larger genetic diversity. Local populations were congregated into a discrete group apart from the typical Chalqueño populations, suggesting that landraces from the Tarasca Mountain Chain region might not be considered as belonging to the Chalqueño race, but they integrate by themselves a different race.     

A simulation model of <Superscript>90</Superscript>Sr daily dynamics in the <Emphasis Type="Italic">soil</Emphasis>–<Emphasis Type="Italic">stand</Emphasis> system of deciduous forests

A simulation model of the ⁹⁰Sr dynamics in the soil and stand components of deciduous forest ecosystems with a 1-day step was developed; this model was used to conduct numerical experiments to clarify the mechanisms of the ⁹⁰Sr behavior. The algorithm allows one to take into account the effect of meteorological, phenological, and physiological factors on the behavior of the radionuclide and simulate different fallout conditions. The results of simulation can be used in the valuation of deciduous forest products. The model is applicable for studying the redistribution of calcium in the stand of deciduous forest ecosystems.     

Phenotypic and Genotypic Diversity of European Chestnut (<Emphasis Type="Italic">Castanea sativa</Emphasis> Mill.) in Slovenia – Opportunity for Genetic Improvement

Phenotypic diversity of 244 chestnut trees was investigated. They originate from the Mediterranean and from two continental regions in Slovenia. In 3 years of analyses, length, diameter, thickness and weight of fruits; length and width of hilum, the pellicle intrusion; shape and colour of fruits; and the embryony were dealt with. The continental trees have smaller fruits than the Mediterranean trees; their fruits show greater variability in shape and the pellicle intrusion is stronger. They also exhibit polyembriony more frequently and they rarely have darker stripes. The sample of 46 trees from all three regions was used for the comparison between the phenotypic and genotypic diversity which had been investigated by RAPD analysis. In both cases, the UPGMA method was used for the classification of the trees into groups. Six pomological clusters were established. The clusters I, II, III and V comprise only the trees from the continental part. The cluster IV comprises nine trees of the marron type from the Mediterranean and one KOZ1 tree with equal pomological characteristics but originating from the continental part. The cluster VI is composed of eight trees from the continental part and one RAV3 tree whose fruits are very small and it originates from the Mediterranean. The Jaccard’s coefficient of similarity is used in order to evaluate genetic relations. On the RAPD dendrogram four clusters of trees are defined. The continental trees are divided into three clusters and exhibit greater genotypic diversity than the Mediterranean trees which form only one cluster. With the RAPD analyses the differentiation of the trees with regard to their pomological traits is determined in 60–90% of the cases. The outcome of the research point to the fact that the Slovene chestnut is a rich source of genetic diversity and is very suitable for further breeding purposes.     

Taxonomic remarks on <Emphasis Type="Italic">Triticum</Emphasis> L. and ×<Emphasis Type="Italic">Triticosecale</Emphasis> Wittm.

The recent treatment of Triticum by Mac Key (2005) (broad species concept) is compared to the classical treatment by Dorofeev et al. (1979, English translation expected) (narrow species concept). A detailed infraspecific treatment was abandoned by Mac Key. Following his revision, names for many of the infraspecific taxa become obsolete. This is regarded to be a disadvantage for biodiversity and genetic resources studies. We propose maintaining ×Triticosecale Wittm. as a nothogenus, with ×T. rimpaui Wittm. for octoploid races, ×T. neoblaringhemii A. Camus for hexaploid races and ×T. semisecale (Mac Key) K. Hammer et A. Filat. (new combination) for tetraploid races.     

The introgression of 2× 1EBN <Emphasis Type="Italic">Solanum</Emphasis> species into the cultivated potato using <Emphasis Type="Italic">Solanum verrucosum</Emphasis> as a bridge

Wild diploid Solanum species with an endosperm balance number (EBN) of one are a rich source of disease resistance, pest resistance, and tuber quality traits. They are not sexually compatible with 4× 4EBN or 2× 2EBN forms of the cultivated potato. In this study, the wild 2× 2EBN Mexican species S. verrucosum (ver) was used as a bridge species to access 2× 1EBN germplasm. Hybrids (V1) were created between ver as a female parent and the 1EBN species S. cardiophyllum, S. chancayense, S. commersonii, and S. trifidum. Most of the V1 hybrids were successfully crossed as females to cultivated 2× 2EBN clones. However, due to stylar barriers, reciprocal crosses were unsuccessful. Additional studies are underway to determine the effectiveness of ver as a bridge to introgress specific traits from 2× 1EBN germplasm into the cultivated potato.     

Chromosome and genome composition of a <Emphasis Type="Italic">Triticum</Emphasis> × <Emphasis Type="Italic">Thinopyrum</Emphasis> hybrid by classical and molecular cytogenetic techniques

Triticum–Thinopyrum amphiploids arose from the need to obtain forage grasses highly resistant to pest, drought, soil salinity and frost and they can be used as efficient bridges to transfer desired genes from wheatgrass species to wheat. One of them is trigopiro SH16 INTA, it was introduced in Argentina in 1947 but its genomic composition was unknown. The aim of this work was to determine the chromosome number and genomic and chromosome composition of trigopiro SH16 INTA in order to use it in breeding programs. The simultaneous use of the in situ hybridization technique with different probes (genomic DNA of Th. ponticum (Podp.) Barkworth et D.R. Dewey, pSc119.2 and pAs1) allowed us to conclude that the chromosome number of trigopiro SH16 is 2n = 42 and the genome composition would be: 14 chromosomes of the B genome, the 2D and 4D chromosome pairs of wheat, 14 chromosomes of the J genome of Thinopyrum and the remaining chromosomes probably belong to the A genome of wheat.     

Acute Effects of Engineered Nanoparticles on the Growth and Gas Exchange of <Emphasis Type="Italic">Zea mays</Emphasis> L.—What are the Underlying Causes?

The increasing use of nanoparticles (nps) in consumer and industrial applications raises concerns about their potential risks to ecosystems and biological systems. The nps can cause negative effects on bacteria, algae, and animals. However, only little is known about their effects on higher plants and the underlying mechanisms. Zea mays L. “Ayrro” was used to investigate effects of ZnO (30–40 nm), TiO₂ (5–15 nm), and Ag (15 nm) nps, in comparison their corresponding bulk counterparts, on germination and early seedling growth. Treatment with nps affected growth positively (ZnO) or negatively (TiO₂, Ag) in a dose-dependent manner. Effects of the corresponding bulk counterparts were either similar (TiO₂) or opposite (ZnO), or even absent (Ag). To separate direct np effects (“nano effects”) from effects of ions released from nps, roots of 5-week-old plants were either treated with Ag nps or Ag⁺ ions with the same effective concentrations of dissolved free Ag⁺ ions, each with or without CaCl₂ to precipitate free Ag⁺ ions as AgCl. Both Ag treatments reduced transpiration and assimilation rate. After addition of CaCl₂, these negative effects disappeared, indicating that acute negative effects can be largely attributed to free Ag⁺ ions, rather than to specific nano effects. Further research with longer exposure times and different growth media could provide further insights in the analysis of np effects on plants.     

<Emphasis Type="Italic">Macrotyloma axillare</Emphasis> and <Emphasis Type="Italic">M. uniflorum</Emphasis>: descriptor analysis,anthocyanin indexes,and potential uses

The purpose of this study was to characterize and identify potential new uses for perennial horsegram (Macrotyloma axillare) and horsegram (M. uniflorum) germplasm in the USDA, ARS collection. Seven morphological and yield parameters were studied in 11 M. axillare and 32 M. uniflorum accessions. A wide variation was found in stem branching, foliage, plant height, seed number, and seed weight. Leaf anthocyanin indexes were significantly higher than control flowers from PI 345729. Phytochemical traits exist in both species for potential use as nutraceuticals, forage, and food for humans.     

Comparison of the efficiency of A–PAGE and SDS–PAGE,ISSRs and RAPDs in resolving genetic relationships among <Emphasis Type="Italic">Triticum</Emphasis> and <Emphasis Type="Italic">Aegilops</Emphasis> species

Species that belong to the genus Triticum L. and the genetically related Aegilops L. genus are important genetic and economic resources because they have an evolutionary relationship with the two main agricultural crops T. aestivum (bread wheat) and T. durum (durum wheat). Therefore, it is important to understand the genetic relationships among the cultivated wheat species and their wild relatives. The latter have a great role in the improvement of cultivated wheat. Molecular markers are the best choice and most reliable means to study these relationships accurately. In this study, we compared the efficiency of the biochemical methods A–PAGE and SDS–PAGE on seed storage proteins and the molecular methods RAPDs and ISSRs to explore the genetic relationships among seven species of Triticum and 20 Aegilops species. Three phylogenetic trees obtained in this study were compared with available classifications and phylogenetic trees constructed earlier for these species. It was noted that the tree based on ISSRs data was the most congruent with those classification and trees. This may be attributed to the fact that ISSRs is more specific, and therefore more reliable. This study is the first to study genetic relationships among all species studied here using biochemical and molecular techniques.     

Are <Emphasis Type="Italic">Melilotus albus</Emphasis> and <Emphasis Type="Italic">M. officinalis</Emphasis> conspecific?

The principal economic species of the genus Melilotus are white sweet-clover (Melilotus albus) and the extremely similar yellow sweet-clover (M. officinalis). Although they are widely recognized as distinct species, some influential references in North America reduce the former to a subspecific rank or even merely a conspecific synonym of the latter. Given their importance and the large numbers of germplasm collections, the doubt needs to be resolved. This review of relevant published evidence finds that in addition to the difference in floral colour, the traditional segregation of the two as distinct species is best supported by very strong reproductive barriers as well as divergent DNA sequences in three barcoding genes. Additional but weaker confirmation of separateness is provided by studies reporting differences in external morphology, biochemistry, seed protein profiles, karyotype and DNA microsatellites.     

<Emphasis Type="Italic">Arnica montana</Emphasis> subsp. <Emphasis Type="Italic">atlantica</Emphasis>: Really a subspecies?

In Arnica montana L. (Asteraceae) two subspecies are described, A. montana subsp. atlantica (AMA), present only on the Iberian Peninsula and A. montana subsp. montana (AMM) with a very wide distribution area. The morphological differences between the two subspecies are small and variable. Therefore, this concept is sometimes questioned. To establish the genetic background of the two subspecies, populations of AMA and AMM together with herbarium samples and DNA Bank material of AMM were tested with 12 microsatellite markers. A. montana propagates by seeds or by clonal propagation of its rhizome. In AMA, clonality was frequent while in AMM only one case of clonality could be identified. Therefore, further results were clone-corrected. Genetically, AMA separated very well from AMM with a G_ST between the subspecies of 0.81, genetically justifying the subspecies concept of A. montana. Genetic variability in AMA (H_exp?=?0.28) was lower than in the AMM populations (H_exp?=?0.70). A somewhat higher fixation index of AMA (F_ST?=?0.17, compared to an F_ST?=?0.08 for AMM) may indicate that geneflow in AMA is a bit more restricted than in alpine AMM. However, the fixation index of AMA is not deviating from Hardy–Weinberg equilibrium. No inbreeding was observed for AMA (F_IS?=?0.10) and AMM (F_IS?=?0.08).     

Genetic characterization of <Emphasis Type="Italic">Pelargonium</Emphasis> L’Hér. germplasm

Fifteen species and eight cultivars of the section Pelargonium (DC.) Harv., two species of the section Ligularia (Sweet) Harv. and three species of the section Cortusina (DC.) Harv. were tested for genetic distance to predict successful combinations of interspecific crossings. 156 randomly amplified polymorphic DNA (RAPD)-bands and 485 double primer RAPD-bands were used for distance analysis. Combined with information on the ploidy level, species were clustered in the expected sections except Pelargonium hirtum (Burm. f.) Jacq., which clustered with the species of the section Cortusina. Different accessions of the same wild species showed a high conformity (67–98 %) comparable to the cultivars (66–70 %).     

Microsatellite analysis of Alpine grape cultivars (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.): alleged descendants of Pliny the Elder’s <Emphasis Type="Italic">Raetica</Emphasis> are genetically related

According to Pliny the Elder and other Greco-Roman geoponics, Raetica was a famous white grape as well as a white wine produced in Raetia, a Province of the Roman Empire. Does Raetica grape have modern descendants? Etymologically and geographically, the white ‘Rèze’ from Valais (Switzerland) would be the best candidate. Using available microsatellite data, we searched for relatives of ‘Rèze’ in our database containing over 1,700 genotypes of grape cultivars from all over the world. Twelve cultivars showing putative first-degree (parent–offspring or full-siblings) or second-degree (grandparent–grandoffspring, uncle–nephew or half-siblings) relationships with ‘Rèze’ were then analysed at 60 microsatellite markers. Calculation of allele sharing and likelihood ratios between competing relationship categories revealed that four cultivars had parent–offspring relationship with ‘Rèze’: ‘Cascarolo Bianco’ (Piedmont, Italy), ‘Arvine Grande’ (Valais, Switzerland), ‘Groppello di Revò’ and ‘Nosiola’ (Trentino, Italy). Given that some of these are also said to be Raetica descendants, we may well be on the tracks of Pliny the Elder’s Raetica grape. However, there is no evidence about the identity of Raetica. Analysis of ancient DNA of grape pips excavated from archaeological sites of the Roman times might provide key information. Our first attempts were unsuccessful, but analysis of additional samples and optimisation of the method could provide groundbreaking results about the identity of the grapes cultivated in classical antiquity.     

Genetics of Wild and Managed Populations of <Emphasis Type="Italic">Leucaena esculenta</Emphasis> Subsp. <Emphasis Type="Italic">esculenta</Emphasis> (Fabaceae; Mimosoideae) in La Montaña of Guerrero,Mexico

Genetic consequences of silvicultural management of Leucaena esculenta subsp. esculenta were analyzed from eight allozyme loci in half-sib families of one wild and one managed in situ (selectively cleared) population from La Montaña de Guerrero region, Central Mexico. A reference sample (including wild, feral and cultivated individual plants) from the states of Morelos, Puebla and Guerrero, Mexico was also analyzed. Genetic variation, population structure and mating system were analyzed. All loci showed high variation (75–87.5% polymorphic loci at 95% level; 2.4–2.8 mean number of alleles per locus). All progenies showed heterozygous deficiency, but both wild and managed parental inbreeding coefficients were negative, suggesting heterosis. Progenies of managed populations differed from those of the wild and reference samples (Nei’s unbiased identities 0.874–0.934). Biparental inbreeding is suggested by Wright’s-statistics ( f = 0.313), and by outcrossing rate estimates: t_m = 0.644 (SE 0.094), and 0.645 (SE 0.193); t_s = 0.576 (SE 0.189), and 0.523 (SE 0.182), for managed and wild samples respectively. Population differentiation is significant (Θ = 0.210). The species is self-incompatible and deviations from the mixed mating model were found. Indirect estimates of products of effective population size (N_e) by the proportion of migrants (N_m) were moderate, as were the N _evalues. Variation due to ecotypic differentiation (related to altitude), prolonged artificial selection, and introduction from other areas is supported. A model of domestication of seed-propagated trees is suggested, based on extensive and in situ selection of locally adapted populations, and their diffusion to other areas.     

The ‘Bavarian Turnip’ — a rediscovered local vegetable variety of <Emphasis Type="Italic">Brassica rapa</Emphasis> L. em. Metzg. var. <Emphasis Type="Italic">rapa</Emphasis>

The Bavarian Turnip (Bayerische Rübe, Brassica rapa L. em. Metzg. var. rapa) is a nearly lost crop today. Until 1900, this local variety was commonly grown in Bavaria for human consumption. The special and very distinct characters of this variety in comparison with recent breeds are preferred by the farmers families and assured the persistence and survival of this turnip in situ (on farm). In the region of Dachau and Freising, located north of Munich, only four farms are known, where this old crop is still grown and maintained. Urgent measures have to be taken to safe this cultural relict for future generations.     

Genetic mapping of the gene for brittle rachis in a <Emphasis Type="Italic">Triticum aestivum</Emphasis>—<Emphasis Type="Italic">Aegilops triuncialis</Emphasis> introgression line

Aegilops triuncialis L. (2n = 4x = 28, genome formula UUCC) has been used to obtain one of the “Arsenal collection”, the distant hybridization of Triticum aestivum L. The introgression line 124/00ⁱ, which was derived from the cross of T. aestivum ‘Rodina' with γ-irradiated pollen of an accession of Ae. triuncialis. However, undesirable genes can be incorporated into the cultivated varieties from Ae. triuncialis. The spikes of Ae. triuncialis disarticulate from stems at a single node at the bottom of the spikes. It was defined as a synaptospermic diaspore. However, the spike of 124/00ⁱ unexpectedly disarticulate below each spikelet showing wedge type of disarticulation. The brittle rachis gene Br ¹²⁴ (B rittle r achis of 124 /00 ⁱ ) of 124/00ⁱ was allelic to Br2 located on the short arm of chromosome 3A. From the microsatellite mapping, the Br ¹²⁴ gene was bracketed by Xbarc19 (20.3 cM) and Xgwm779.1(14.3 cM) on the short arm of chromosome 3A. The present study suggested that the dominant mutation from synaptospermic diaspore to wedge type disarticulation occurred in the gamete of Ae. triuncialis when Ae. triuncialis pollen was treated with γ-irradiation.     

The third glume phenotype is associated with rachilla branching in the spikes of tetraploid wheat (<Emphasis Type="Italic">Triticum</Emphasis> L.)

We investigated the new inflorescence architectural character “three glumes” and a new status of ramification in tetraploid wheat. Using 9 tetraploid accessions with “turgidum type of branching”, the segregation of branched spike and the third glume indicated the complete linkage of genes for both phenotypes. The rachilla were elongated and bore florets at basal nodes while bearing spikelets at the apical nodes in T. durum Desf. TRI 9644 and T. turgidum L. PI 67339. The phenotype was different from “sham-ramification” in Triticum jakubzineri Udacz. et Schachm., with florets at basal and apical nodes of elongated spikelet rachilla. We confirmed a new status of ramification, “false-true ramification”. It was considered that the “false-true ramification” was determined by the shr2 gene in the long arm of chromosome 2A because the ramification of PI 67339 and TRI 9644 was supposed to be allelic. The segregation of “sham-ramification” and the third glume also indicated the complete linkage of genes for both phenotypes. Thus we concluded that the presence of third glume phenotype is associated with rachis and rachilla branching in the spikes of tetraploid wheat. The present study confirmed the existence of three distinct types of spike ramification, whose classification is not entirely unified: (a) “true ramification”—“branched spike”—“genuine branching”—“turgidum type of branching”, (b) “false ramification”—“pseudo-branched spike”—“sham ramification”—“vavilovii type of branching” and (c) “false-true ramification”.     

Microsatellite genotyping of apple (<Emphasis Type="Italic">Malus</Emphasis> × <Emphasis Type="Italic">domestica</Emphasis> Borkh.) genetic resources in the Netherlands: application in collection management and variety identification

A highly informative set of 16 microsatellite markers was used to fingerprint 695 apple accessions from eight Dutch collections. Among the total sample, 475 different genotypes were distinguished based on multi-locus microsatellite variation, revealing a potential redundancy within the total sample of 32%. The majority of redundancies were found between collections, rather than within collections. No single collection covered the total observed diversity well, as each collection consisted of about 50% of unique accessions. These findings reflected the fact that most collection holders focus on common Dutch varieties, as well as on region-specific diversity. Based on the diversity patterns observed, maintenance of genetic resources by a network of co-operating collection holders, rather than by collecting the total diversity in a single collection appears to be an efficient approach. Comparison of microsatellite and passport data showed that for many accessions the marker data did not provide support for the registered variety names. Verification of accessions showed that discrepancies between passport and molecular data were largely due to documentation and phenotypic determination errors. With the help of the marker data the varietal names of 45 accessions could be corrected. Microsatellite genotyping of apple appears to be an efficient tool in the management of collections and in variety identification. The development of a marker database was considered relevant as a reference instrument in variety identification and as a source of information about thus far unexplored diversity that could be of interest in the development of new apple varieties.     

Genetic Structure of <Emphasis Type="Italic">Lycopersicon pimpinellifolium</Emphasis> (Solanaceae) Populations Collected after the ENSO Event of 1997–1998

The greatest extent of genetic variation and outcrossing for Lycopersicon pimpinellifolium occurs in northern Peru. This is also the area most affected by EI Niño Southern Oscillation (ENSO). Using morphological and the molecular markers SSRs and AFLPs, we studied the genetic structure of L. pimpinellifolium populations collected after the ENSO event of 1997–1998. This was the most intense in the last century and caused a vast increase in the size of L. pimpinellifolium populations. Populations in the area surveyed were not regionally differentiated. We did not find any cline or eco-geographic association for genetic diversity, and positive correlations between genetic and geographic distances were found only at very short distances. Flooding and water streams caused by ENSO might have facilitated a periodical seed migration from distant areas. Gene flow between populations could then occur, facilitated by the increase in the population sizes of plants and pollinators and by the high levels of stigmatic exsertion. Results revealed a significant lack of heterozygotes in comparison with those expected in a panmictic population without consanguinity. A high degree of endogamy was found in all populations. In this context, endogamy can be explained by the occurrence of crosses between relatives rather than by autogamy. In an area intensely disturbed by ENSO, we found a population that had not been reported by earlier collectors in this region. This yellow-fruited population remained morphologically and molecularly differentiated from all L. pimpinellifolium and L. esculentum populations analyzed.