The genetic relationship and structure of some natural interspecific hybrids in <Emphasis Type="Italic">Prunus</Emphasis> subgenus <Emphasis Type="Italic">Prunophora</Emphasis>, based on nuclear and chloroplast simple sequence repeats

In the subgenus Prunophora of the genus Prunus, many transitional traits presented in interspecific hybrids, the so-called ‘new species’, were frequently named due to the complicated botanical classification system. In this study, we used 16 nuclear simple sequence repeats (nSSRs) and 10 chloroplast simple sequence repeats (cpSSRs) to evaluate genetic relationships among 42 accessions, which included 15 putative interspecific hybrids, and then to reveal the speciation and differentiation in the subgenus Prunophora. In total, 231 and 27 alleles were observed in nSSRs and cpSSRs respectively; and with cpSSRs 20 haplotypes were revealed among the accessions. Furthermore, the haplotype and genetic structure analysis implied that (1) Prunus simonii Carr. might be a subspecies or a forma of Prunus salicina L., rather than an interspecific hybrid between P. salicina and Prunus armeniaca L., (2) Prunus limeixing Zhang et Wang was derived from a natural hybrid with P. salicina as its maternal progenitor and P. armeniaca as the female parent, and (3) Prunus cathayana Fu et al. (or kernel-using apricot) was an interspecific hybridization species of P. armeniaca (maternal parent) and Prunus sibirica L. (female parent). These results will be useful for clarifying the problems in the botanical classification, and facilitate the conservation and management of plum and apricot genetic resources in the Chinese National Germplasm Repository for Plums and Apricots.     

Genetic diversity in tolerance of wild <Emphasis Type="Italic">Avena</Emphasis> species to aluminium (Al)

An evaluation of diversity of aluminium (Al) tolerance of 180 genebank accessions of diploid, tetraploid and hexaploid of wild Avena species from the world collection of the N.I. Vavilov Institute of Plant Genetic Resources (VIR) showed that the accessions with a high degree of aluminium tolerance belonged to the diploids A. canariensis, A. longiglumis and A. wiestii, the tetraploids A. barbata, A. vaviloviana, and hexaploids A. ludoviciana and A. sterilis. A comparison of the data on Al tolerance with the soil conditions demonstrated that most highly tolerance accessions tend to be collected on different type of soils. According to the results of the principal component analysis, preliminary screening for Al tolerance can be carried out among hexaploid species with higher degree of plant resistance to pathogens.     

Evaluation of genetic resources in the genus <Emphasis Type="Italic">Asparagus</Emphasis> for resistance to <Emphasis Type="Italic">Asparagus virus 1</Emphasis> (AV-1)

Forty-four Asparagus officinalis cultivars, gene bank accessions and breeding lines as well as thirty-four accessions of wild relatives of Asparagus were evaluated for resistance to Asparagus virus 1. Three different test strategies were developed for the assessment of individual plants: (1) natural infection under field conditions, or two vector-mediated infection assays using the green peach aphid Myzus persicae (2) in an insect-proof gauze cage or (3) in a climate chamber. The AV-1 infections were verified by DAS-ELISA and RT-PCR approaches. All tested 660 individual plants of A. officinalis germplasm were susceptible to AV-1 infection. In contrast, in 276 plants of 29 Asparagus wild accessions no virus infection could be detected. These resistant accessions comprised of nineteen diploid, tetraploid and hexaploid species of both the Eurasian clade and the African clade of the asparagus germplasm. Data of the AV-1 resistance evaluation are discussed in relation to the genetic distance of the resistance carrier and potential application in breeding.     

New <Emphasis Type="Italic">Citrus</Emphasis> chloroplast haplotypes revealed by molecular markers using Algerian and Spanish accessions

Thirty-seven chloroplast molecular markers were used to evaluate the genetic diversity and infer the phylogenetic relationship of 24 Algerian Citrus accessions from the Institut Technique de l′Arboriculture Fruitière et de la Vigne germplasm bank. The reliability and consistence of the clustering distribution was further asserted including 5 Spanish accessions from the Instituto Valenciano de Investigaciones Agrarias. The accessions were positioned on a phylogenetic tree of the genus Citrus based on previous analyses of the whole sequence of citrus chloroplast. Algerian accessions clustered into two main clades mostly differentiated by the occurrence of either mandarin or pummelo chloroplast types. All 7 mandarins analyzed were grouped in the same clade while the other cluster subdivided in 4 groups, included 1 lumia, 3 lemons, 2 grapefruits and 11 sweet oranges. Algerian grapefruit accessions were grouped together with the pummelos in a single cluster while all sweet oranges formed an independent and homogenous clade. Interestingly, the lemons studied were clustered in 3 different subclusters while Citrus lumia genotype was isolated in a different group. These results suggest that in contrast to the studied Algerian mandarins or sweet oranges, that share all the same mandarin or sweet orange chloroplast haplotype, the high diversity of current lemon accessions is at least partially correlated with the identity of different pummelo progenitors which evolved from a common ancestor. In addition, the data indicate that Citrus lumia is a new type of citrus chloroplast that appears to be phylogenetically related to the chloroplasts of the pummelo and micrantha group.     

Diversity of <Emphasis Type="Italic">Citrus</Emphasis><Emphasis Type="Italic">depressa</Emphasis> Hayata (Shiikuwasha) revealed by DNA analysis

Citrus depressa Hayata is an indigenous mandarin species on the Ryukyu Islands located in the subtropical region of Japan. We deduced its phylogenetic relationships by evaluating accessions grown on various Ryukyu Islands via cleaved amplified polymorphic sequence analysis of cpDNA and sequence-related amplified polymorphism (SRAP). The cpDNA results indicated that C. depressa could be classified into two types. SRAP revealed patterns of diversity within C. depressa consistent with our cpDNA results. These results indicate that maternal origin may influence or is correlated with the constitution of the nuclear genome of C. depressa. Another Japanese mandarin species, Citrus tachibana (Makino) Tanaka was distinguished from C. depressa by SRAP markers. Moreover, both C. depressa and C. tachibana could be distinguished from other Citrus species. Our results suggest that Japanese mandarin possesses a characteristic genome with the genus Citrus.     

Complete chloroplast DNA sequences of Georgian indigenous polyploid wheats (<Emphasis Type="Italic">Triticum</Emphasis> spp.) and B plasmon evolution

Three types of plasmon (A, B and G) are present for genus Triticum. Plasmon B is detected in polyploid species - Triticum turgidum L. and Triticum aestivum L. By now, 21 complete sequences of chloroplast DNA of the genus Triticum is published by different authors. Many inaccuracies can be detected in the sequenced chloroplast DNAs. Therefore, we found it necessary to study of plasmon B evolution to use only those sequences obtained by our method in our laboratory. Complete nucleotide sequences of chloroplast DNA of 11 representatives of Georgian wheat polyploid species were determined. Chloroplast DNA sequencing was performed on an Illumina MiSeq platform. Chloroplast DNA molecules were assembled using the SOAPdenovo computer program. Using T. aestivum L. subsp. macha var. palaeocolchicum as a reference, 5 SNPs were identified in chloroplast DNA of Georgian indigenous polyploid wheats. 38 and 56 bp inversions were observed in paleocolchicum subspecies. The phylogeny tree shows that subspecies macha, durum, carthlicum and palaeocolchicum occupy different positions. According the simplified scheme based on SNP and indel data the ancestral, female parent of all studied polyploid wheats is an unknown X predecesor, from which four lines were formed.     

Genetic relationship of diploid wheat (<Emphasis Type="Italic">Triticum</Emphasis> spp.) species assessed by SSR markers

Genetic diversity of 139 accessions of diploid Triticum species including Triticum urartu, Triticum boeoticum and Triticum monococcum was studied using 11 SSR (simple sequence repeats) markers. A total of 111 alleles with an average of 10 alleles per locus were detected. The polymorphism information content (PIC) of each SSR marker ranged from 0.30 to 0.90 with an average value of 0.62. Among the three Triticum species T. urartu had the highest number of total alleles (Na?=?81), private alleles (Npa?=?15) and showed higher genetic diversity (Hex?=?0.58; PIC?=?0.54). The genotypes from Turkey exhibited the highest genetic diversity (PIC?=?0.6), while the least diversity was observed among 4 Georgian accessions (PIC?=?0.11). Cluster analysis was able to distinguish 139 wheat accessions at the species level. The highest genetic similarity (GS) was noted between T. boeticum and T. monococcum (GS?=?0.84), and the lowest between T. urartu and T. monococcum (GS?=?0.46). The grouping pattern of the PCoA analysis corresponded with cluster analysis. No significant differences were found in clustering of T. urartu and T. monococcum accessions with respect to their geographic regions, while within T. boeoticum species, accessions from Iran were somewhat associated with their geographical origin and clustered as a close and separate group. The results from our study demonstrated that SSR markers were good enough for further genetic diversity analysis in einkorn wheat species.     

Polymorphism of <Emphasis Type="Italic">Got2</Emphasis> DNA sequences sheds light on <Emphasis Type="Italic">Aegilops tauschii</Emphasis> Coss. intraspecies divergence and origin of <Emphasis Type="Italic">Triticum aestivum</Emphasis> L.

DNA sequences of nuclear gene Got2 was studied in 60 accessions of Aegilops tauschii, 29 of subsp. tauschii and 31 of subsp. strangulata. It was found that Got2 allozyme polymorphism in Ae. tauschii is due to a single, unique, mutation which led to replacement of glutamic acid by isoleucine in residue 256 of the enzyme molecule, encoded by Got2. As revealed by Got2 DNA sequences variation, initially in its history Ae. tauschii was presented by subsp. strangulata, and among phylogenetic lineages of subsp. strangulata, the lineage “t-9¹s” (TauL3) is the most ancient, a relict one. Subspecies tauschii is relatively “young”. Initially it was presented by the lineage marked by combination of allozyme alleles Got2 ¹⁰⁵ and Acph1 ¹⁰⁰. In the past it inhabited the Continental area from Caucasia to Pakistan, but later on it was forced out by newly originated, now—a major lineage of subsp. tauschii, marked by Got2 ¹⁰⁰. This lineage extended the Continental area of the species up to Kirgizstan, but actually failed to penetrate into pre-Caspian area, occupied by subsp. strangulata. These results essentially differ from those obtained previously, using chloroplast DNA (cpDNA) sequences polymorphism. As revealed by cpDNA, the major, “usual”, subsp. strangulata (TauL2) is “younger” than subsp. tauschii, which resided on phylogenetic tree between relict lineage “t-9¹s”of subsp. strangulata—and major subsp. strangulata. But both cpDNA and Got2 DNA sequences indicate that the level of genetic variation in subsp. tauschii is much lower than in subsp. strangulata. According to Got2 DNA sequences variation, it was Ae. tauschii subsp. strangulata lineage “k-109″ which donated genome D to Triticum aestivum L. This lineage includes accessions: k-109 from South-Eastern Precaspian Azerbaijan; KU-2105, KU-2159 from Western Precaspian Iran; KU-2080 from Eastern Precaspian Iran.     

Remarks on genetic diversity and relationship of <Emphasis Type="Italic">Punica protopunica</Emphasis> and <Emphasis Type="Italic">P. granatum</Emphasis> assessed by molecular analyses

Here, two Punica species, viz., P. protopunica Balf. fil., reported as native to Socotra, and P. granatum L., were compared for the first time. Analysis of one P. protopunica and eleven P. granatum accessions was performed using three molecular markers, i.e., sequence related amplified polymorphism (SRAP), target region amplification polymorphism (TRAP), and intron targeted amplified polymorphism (ITAP), along with analysis of pgWD40 sequences, a gene involved in anthocyanin biosynthesis. All markers revealed the relationship between the two species and placed them at 33% similarity. SRAP, TRAP, and ITAP generated a total of 299, 260, and 160 bands, respectively. Of these, 78, 74, and 41 bands were specific for P. protopunica, and 92, 85, and 57 bands, respectively, were shared between both species. Sequence analysis of pgWD40~870 bp amplicons exhibited 100% identity among P. granatum accessions and 98% identity to that of P. protopunica. Phylogenetic analysis of WD40 sequences from monocot and dicot species, including both Punica species confirmed the relation between P. protopunica and P. granatum, supporting earlier reports that P. protopunica could be an ancestral species of P. granatum. Furthermore, the genetic diversity among and within P. granatum accessions from Egypt (3), Mexico (5), and Yemen (3) was assessed. Molecular marker-based relationships among region-bulked accessions was approximately the same (~90% similarity), whereas the degree of genetic variation was altered within each region. Specific bands (alleles) for accessions of each region along with those shared among them were identified. Thus, these bands could be used for pomegranate genotyping and breeding programs.     

Characterization of a world collection of <Emphasis Type="Italic">Agropyron cristatum</Emphasis> accessions

The genetic diversity was studied of 115 Agropyron cristatum accessions from 17 countries. Tetraploids were the most common (74.8%), followed by diploid (16.3%) and hexaploid (6.9%). We observed a relation between geographic distribution and ploidy level. The tetraploids, the most widespread, were found from Europe through Russia to East Asia. The diploids appeared over the same general range, except in Turkey, Iran and Georgia where no diploid accessions were found. Hexaploid accessions mainly came from a region comprising the east of Turkey, the north of Iran and Georgia. A selection of 71 accessions, including all three ploidy levels, were analyzed by capillary electrophoresis using six wheat simple sequence repeat (SSR) markers. All markers presented high levels of polymorphism, generating 166 different alleles ranging in size between 84 and 256 bp. Based on polymorphic information content values obtained (0.579–0.968), all the SSRs were classified as informative markers (values?>?0.5). According to the dendrogram generated, all the A. cristatum accessions were distinctly classified. Diploid, tetraploid and hexaploid accessions are not clearly differentiated from each other on the basis of SSR markers. A field experiment was conducted to morphologically characterize 18 accessions including the three ploidy levels. Significant differences were found between the accessions in spike length, spike width and number of spikelets per spike. All the cytological, molecular, and morphological data demonstrate the high genetic diversity present in A. cristatum, making it a valuable resource for future breeding programs.     

Characteristics of the root system in the diploid genome donors of hexaploid wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

Wild crop relatives are of considerable interest in plant breeding and significant efforts have been made to transfer their genetic variation into modern crops. Of the three diploid progenitors of bread wheat (Triticum aestivum L.), only Aegilops tauschii Coss. has been explored and exploited and only for some above ground characteristics. The three wild progenitors (Aegilops speltoides Tausch., Triticum urartu Tumanian ex Gandilyan, and Aegilops tauschii) have never been assayed for root traits. Here we report such a root study, and include Triticum monococcum L. subsp. boeoticum (Boiss.) Hayek and T. turgidum L. subsp. dicoccoides (Koern. ex Asch. et Graebn.) Thell. Fifteen accessions were selected from the above wild species and tested in the presence of one bread wheat cultivar Pavon F76. Significant variation was observed between and within the taxa. Of all accessions tested, cv. Pavon F76 had the smallest root system at maturity while A. speltoides had the largest root system. Moreover, Aegilops spp. had larger mean values for root biomass when compared with Triticum spp. These results suggest there is significant unexplored potential for the use of wheat wild relatives in wheat breeding to improve the root system, or to develop synthetic mapping populations to study root traits.     

Agro-morphological traits of <Emphasis Type="Italic">Cicer reticulatum</Emphasis> Ladizinsky in comparison to <Emphasis Type="Italic">C. echinospermum</Emphasis> P.H. Davis in terms of potential to improve cultivated chickpea (<Emphasis Type="Italic">C. arietinum</Emphasis> L.)

Germplasm collections of C. reticulatum and C. echinospermum are limited, while both species face threats from over-grazing and habitat change in their natural environments. Recently many new accessions of C. reticulatum and C. echinospermum were collected in east and south-east Anatolia (Turkey) but they have not yet been evaluated for agro-morphological traits. Therefore, the current study investigated agro-morphological traits of new germplasm sources of C. reticulatum and C. echinospermum and evaluated resistance to biotic and abiotic stresses for chickpea improvement. The most attractive agro-morphological traits were canopy width, number of stems and pods per plant and biological yield. The most productive accessions of C. reticulatum and C. echinospermum had 712 and 625 pods per plant, respectively. Two distinct seed, flower and leaf shapes were found in accessions of C. echinospermum. Path analyses indicated that biological yield and harvest index had the most direct influence on seed yield in both species. Factor analyses showed that high seed yield in C. reticulatum depended on high biological yield and number of pods per plant, whereas high seed yield in C. echinospermum depended on harvest index. It was concluded that most accessions of C. reticulatum and C. echinospermum were not only resistant to some biotic and abiotic stresses but also had hidden alleles that could produce transgressive segregation in crosses to cultivated material.     

Cross-transferability of SSR markers in <Emphasis Type="Italic">Osmanthus</Emphasis>

Developing a molecular tool kit for hybrid breeding of Osmanthus species and related genera is an important step in creating a systematic breeding program for this species. To date, molecular resources have been aimed solely at Osmanthus fragrans with little work to develop markers for other species and cultivars. The objectives of this study were to (1) determine cross-transferability of O. fragrans and Chionanthus retusus derived SSRs in diverse Osmanthus taxa, (2) quantify the influence of locus-specific factors on cross-transferability, and (3) determine the genetic relationships between accessions. We tested 70 SSR markers derived from O. fragrans and C. retusus in 24 accessions of Osmanthus. Sixty-seven markers showed transfer to at least one other Osmanthus species with an overall transfer rate of 84% of loci across taxa. Genotyping with 42 microsatellite markers yielded a total of 367 loci. Number of alleles per locus ranged from 2 to 17 with a mean of 8.7 ± 4.8. Mean observed and expected heterozygosities were 0.560 ± 0.225 and 0.688 ± 0.230, respectively. Percent of polymorphic loci ranged from 40% in Osmanthus delavayi to 100% in O. fragrans. Osmanthus fragrans had the highest mean number of alleles per locus (4.2) while O. delavayi had the lowest (1.1). A reduced suite of eight-markers can distinguish between accessions with non-exclusion probabilities of identity from 3.91E?⁰⁴ to 2.90E?⁰⁷. The SSR markers described herein will be immediately useful to characterize germplasm, identify hybrids, and aid in understanding the level of genetic diversity and relationships within the cultivated germplasm.     

Diversity and differentiation of <Emphasis Type="Italic">Oryza sativa</Emphasis> and <Emphasis Type="Italic">O. rufipogon</Emphasis> in Indonesia

Analysis of the genetic structure of Indonesian Oryza sativa and O. rufipogon using neighbour-joining trees based on single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers revealed that O. sativa in Indonesia is separated from O. rufipogon. Accessions of O. sativa in this study were differentiated into two major groups, indica and tropical japonica, excluding some varieties. SSR and SNP markers revealed the high value of differentiation (F _ST) and genetic distance (D) between indica and tropical japonica and we discovered four loci by SNP markers and one locus by SSR markers that play a role in differentiation between indica and tropical japonica. Interestingly, genetic diversity (H) in O. rufipogon was lower than that in O. sativa, however H in O. rufipogon was the highest and H in tropical japonica was the lowest when O. sativa was divided into two groups. Inbreeding coefficient (Fst) showed evidences that gene flow (Nm) between species and within species might be one of the mechanisms related to the diversification and differentiation of Indonesian rice germplasm by asymmetric pattern between species and within O. sativa as revealed by SSR and SNP markers. In addition, we found evidences on stabilizing selection in Indonesian rice germplasm and they might be the reasons why Indonesian rice germplasm did not differentiate due to source location of landrace. However, we found a weak relation between SSR and SNP markers probably due to highly polymorphic in SSR and the different properties of both markers.     

Relationship between spike morphology and habitat of four <Emphasis Type="Italic">Aegilops</Emphasis> species of section Sitopsis

This study examines the relationship between spike morphology and natural habitat for 84 accessions of four Aegilops species, belongs to section Sitopsis, Ae. bicornis, Ae. longissima, Ae. searsii, and Ae. sharonensis in genus Aegilops, section Sitopsis, wild relatives of Triticum aestivum L. These species are considered valuable genetic resources for future cultivation and breeding of domesticated wheat. The goals of the study were to: (1) document variation in spike morphology among these four species; (2) examine the relationship between spike morphology and native habitat; (3) document geographical distribution of distinct spike morphology; and (4) examine the relationship between spike morphology and heading time and value for these four species. The results reveal significant differences in spike morphology among species of section Sitopsis. The most noteworthy variation involved the absence/presence of lateral awn, such that species with lateral awn were restricted in coastal, though species without lateral awn were mainly distributed in inland. This suggests that local climate may be a determinant of variation in lateral awn, and that this trait may be subject to convergent evolution. Differences in heading time in sympatric area were also observed. The differences may enhance species divergence and could represent a lead speciation event. The results of this study will facilitate identification of populations or accessions of wild wheat with favorable traits and/or novel adaptive genes.     

Analysis of genetic diversity and evolutionary relationships among hexaploid wheats <Emphasis Type="Italic">Triticum</Emphasis> L. using LTR-retrotransposon-based molecular markers

The origin, diversity and distribution of hexaploid wheat still remain somewhat unclear. In this study we examined the patterns of genetic diversity and phylogenetic relationships of seven hexaploid wheat species using integration site polymorphism of the LTR retrotransposons. Forty-eight accessions (most of them aboriginal) of seven wheat species from different geographical regions were studied using sequence-specific amplification polymorphisms. Phylogenetic relationships among species were constructed with SplitsTree 4.10 based on Dice’s matrices. Genetic distances between the accessions clustered with PAST software were estimated by principal component analysis. All the accessions differentiated into two main groups, one including European spelt and the other combining common, club and Indian dwarf (shot) wheat with the Asian spelt. The spelt species T. macha, T. vavilovii and spelt spike (speltoid) free-threshing T. petropavlovskyi were intermediate between the two groups. The separation of these spelt species from all other accessions was determined by differences in the A genome. European spelt was subdivided into Central European and Spanish branches. As different genetic pools were characteristic of European and Asian spelt, European spelt could not originate directly from the Asian one. Supposedly, the A genome mostly harbors the species-forming or taxonomically important genes that distinguish spelt species from free-threshing ones, which group together with Asian spelt. Grouping of Asian spelt with free-threshing wheat suggests their close relatedness and confirms the hypothesis that free-threshing hexaploid wheats originated from the Asian spelt ancestor.     

Genetic diversity of dihydrochalcone content in <Emphasis Type="Italic">Malus</Emphasis> germplasm

Dihydrochalcones, beneficial phenolic compounds, are abundant in Malus Mill. species, particularly in vegetative tissues and seeds. Phloridzin (phloretin 2′-O-glucoside) is the primary dihydrochalcone in most Malus species including cultivated apple, Malus?×?domestica Borkh. A few species contain sieboldin (3-hydroxyphloretin 4′-O-glucoside) or trilobatin (phloretin 4′-O-glucoside) in place of phloridzin, and interspecific hybrids may contain combinations of phloridzin, sieboldin, and trilobatin. Proposed health benefits of phloridzin include anti-cancer, antioxidant, and anti-diabetic properties, suggesting the potential to breed apples for nutritional improvement. Sieboldin and trilobatin are being investigated for nutritional value and unique chemical properties. Although some of the biosynthetic steps of dihydrochalcones are known, little is known about the extent of variation within Malus germplasm. This research explores the genetic diversity of leaf dihydrochalcone content and composition in Malus germplasm. Dihydrochalcone content was measured using high performance liquid chromatography (HPLC) from leaf samples of 377 accessions, representing 50 species and interspecific hybrids from the USDA-Agricultural Research Service (ARS) National Plant Germplasm System Malus collection. Within the accessions sampled, 284 accessions contained phloridzin as the primary dihydrochalcone, one had only trilobatin, two had phloridzin and trilobatin, 36 had sieboldin and trilobatin, and 54 had all three. Leaf phloridzin content ranged from 17.3 to 113.7 mg/g with a heritability of 0.76 across all accessions. Beyond the potential of dihydrochalcones for breeding purposes, dihydrochalcone composition may be indicative of hybridization or species misclassification.     

Phylogenetic relationships within <Emphasis Type="Italic">Lactuca</Emphasis> L. (Asteraceae), including African species,based on chloroplast DNA sequence comparisons

Lettuce (Lactuca sativa L.) belongs to the genus Lactuca L. and is an important vegetable worldwide. Over the past decades, there have been many controversies about the phylogeny of Lactuca species due to their complex and diverse morphological characters and insufficient molecular sampling. In this study we provide the most extensive molecular phylogenetic reconstruction of Lactuca, including African wild species, using two chloroplast genes (ndhF and trnL-F). The sampling covers nearly 40 % of the total endemic African Lactuca species and 34 % of the total Lactuca species. DNA sequences from all the subfamilies of Asteraceae in Genebank and those generated from Lactuca herbarium samples were used to establish the affiliation of Lactuca within Asteracaeae. Based on the subfamily tree, we selected 33 ndhF sequences from 30 species and 79 trnL-F sequences from 48 species to infer relationships within the genus Lactuca using randomized axelerated maximum likelihood and Bayesian inference analyses. Biogeographical, chromosomal and morphological character states were reconstructed over the Bayesian tree topology. We conclude that Lactuca contains two distinct phylogenetic clades—the crop clade and the Pterocypsela clade. Other North American, Asian and widespread species either form smaller clades or mix with the Melanoseris species. The newly sampled African endemic species probably should be treated as a new genus.     

A haplotype specific to North European wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.)

A previous study indicated decreased DNA content of chromosome 4A in the wheat (Triticum aestivum L. cv. Tähti) compared to cvs. Chinese Spring and Rennan. Here we show that the lower 4A DNA content is associated with a specific haplotype in the distal part of 4AL. In 41 cultivars of bread wheat (T. aestivum L.), including cv. Tähti, a common haplotype was identified in the linkage disequilibrium region on the long arm of chromosome 4A (4AL). The haplotype (haplotype A) is characterized by 7 SSR and 5 EST marker alleles, including five zero-alleles. Haplotype A was found in 46 % of the Swedish/Finnish/Estonian spring wheat genotypes, while only one of the modern wheat accessions from Germany carried the same haplotype. Fluorescent cytometry analysis linked haplotype A to diminished DNA content of chromosome 4A. The haplotype was introduced into the Canadian and US breeding programs at the beginning of the twentieth century (cvs. Marquis, Thatcher, Ruby) from the common progenitor, the Polish landrace Fife, and it is still found in modern wheat germplasm in these countries. Zero-alleles characteristic for haplotype A were also detected in several accessions of European spelt (Triticum spelta L.), and in two accessions of tetraploid Triticum timopheevii Zhuk. The presence of haplotype A in European spelt indicates the considerable antiquity of the haplotype, as it must have been inherited from the hexaploid or tetraploid parent of spelt in at least one hybridization event.