Hordeum Murinum Research Articles

Copper, zinc and lead biogeochemistry in aquatic and land plants from the Iberian Pyrite Belt (Portugal) and north of Morocco mining areas.

The ability of aquatic (Juncus effusus L., Scirpus holoschoenus L., Thypha latifolia L. and Juncus sp.) and land (Cistus ladanifer L., Erica andevalensis C.-R., Nerium oleander L., Isatis tinctoria L., Rosmarinus officinalis L., Cynodon dactylon L. and Hordeum murinum L.) plants from Portugal (Aljustrel, Lousal and São Domingos) and Morocco (Tighza and Zeida) mining areas to uptake, translocate and tolerate heavy metals (Cu, Zn and Pb) was evaluated. The soils (rhizosphere) of the first mining area are characterized by high acidity conditions (pH 2-5), whereas from the second area, by alkaline conditions (pH 7.0-8.5). Physicochemical parameters and mineralogy of the rhizosphere were determined from both areas. Chemical analysis of plants and the rhizosphere was carried out by inductively coupled plasma emission spectrometry. The sequential chemical extraction procedure was applied for rhizosphere samples collected from both mining areas. In the acid conditions, the aquatic plants show a high capacity for Zn bioaccumulation and translocation and less for Pb, reflecting the following metal mobility sequence: Zn > Cu > Pb. Kaolinite detected in the roots by infrared spectroscopy (IR) contributed to metal fixation (i.e. Cu), reducing its translocation to the aerial parts. Lead identified in the roots of land plants (e.g. E. andevalensis) was probably adsorbed by C-H functional groups identified by IR, being easily translocated to the aerial parts. It was found that aquatic plants are more efficient for phytostabilization than bioaccumulation. Lead is more bioavailable in the rhizosphere from Morocco mining areas due to scarcity of minerals with high adsorption ability, being absorbed and translocated by both aquatic and land plants.

Genetic diversity and geographic distribution of variation of Hordeum murinum as revealed by retroelement insertional polymorphisms in Iran

Hordem murinum is a widespread weedy/wild species, growing in different ecological conditions in Iran. Populations of H. murinum subsp. glaucum (2n = 2x = 14) and subsp. leporinum (2n = 4x, 6x = 28, 42) are found in this region. Inter-retroelement amplified polymorphism (IRAP) markers were used to analyse the genetic diversity of 57 accessions of H. murinum from different regions of Iran, and to examine patterns of diversity related to the taxonomy and geography. Eight IRAP primer combinations amplified a total of 241 distinct DNA fragments sized 150-1400 bp, from which 236 (97.9%) were polymorphic. On average, each primer combination amplified about 30.12 fragments (ranged from 23 to 34) in PCR. The patterns of genetic diversity were closely correlated with taxonomic groups, ploidy levels and geographic origin. Along with the high genetic diversity, three geographic sub-genepools were evident, 1: in the North-Northeast region along the Alborz Mountains, 2: in the West-Northwest region along the Zagros Mountains, and 3: in the Central — Southern region. The genetic diversity in diploids was higher than polyploids. Also genetic diversity in W-NW region along the Zagros Mountains was considerably higher than that of the other regions.

First Report of Wheat mosaic virus Infecting Wheat in Western Australia.

In eastern Australia, there have been several as yet unconfirmed reports of Wheat mosaic virus (WMoV) infecting wheat (3). WMoV, previously known as High plains virus (HPV), is transmitted by the wheat curl mite (WCM, Aceria tosichella). It is often found in mixed infections with Wheat streak mosaic virus (WSMV), also transmitted by WCM (2,3). WSMV was first identified in Australia in 2003 (3). In October 2012, stunted wheat plants with severe yellow leaf streaking were common in a field experiment near Corrigin in Western Australia consisting of nine wheat cultivars. These symptoms were also common in two commercial crops of wheat cv. Mace near Kulin. Leaf samples (one per plant) from each location were tested by ELISA using specific antiserum to WMoV (syn. HPV 17200, Agdia, Elkhart, IN). At the field experiment, 20 leaf samples were collected at random from each wheat plot (4 replicates) and tested individually by ELISA. WMoV incidence was 5% for cv. Yipti, 16% for cvs Emu Rock, Wyalkatchem and Mace, 22% for cvs. Corack, Fortune, Calingiri, and Magenta, and 55% for cv. Cobra. From the two commercial wheat crops, 100 leaf samples were collected at random from each and tested by ELISA. WMoV incidence was 2 and 4%. In addition, 50 leaf samples of Hordeum leporinum (barley grass) and 20 of Lolium rigidum (annual ryegrass) were collected and tested by ELISA. WMoV incidence was 2% in H. leporinum, but 0% in L. rigidum. Infected H. leporinum plants were symptomless. Symptomatic wheat leaf samples from both sites were tested by RT-PCR using WMoV specific primers designed from its RNA3 sequence (1). The PCR products (339 bp) were sequenced and lodged in GenBank (Accession Nos KC337341 and KC337342). WMoV isolates from Corrigin (WA-CG12) and Kulin (WA-KU12) had identical sequences. When the nucleic acid sequences of WA-CG12 and WA-KU12 were compared with those of the three other WMoV isolates on GenBank, they had 100% nucleotide sequence identity with a Nebraska isolate (U60141), and 99.7% identity to two United States sweet corn isolates (AY836524 and AY836525). Ten symptomatic wheat plants were collected from each location, transplanted into pots and leaf samples tested individually for WMoV and WSMV (07048, Loewe, Germany) by ELISA. All were infected with both viruses and infested with WCM. WCM-infested glumes (>10 WCM/glume) were placed on the leaf sheaths of 60 wheat plants cv. Calingiri (35 with WA-CG12 and 25 with WA-KU12) and 13 sweet corn plants cv. Snow Gold (WA-CG12 only). In addition, 20 wheat and 10 sweet corn plants were left without infested glumes to be uninoculated controls. All 60 WCM-inoculated wheat plants became stunted with severe leaf streaking. When leaf samples from each plant were tested by ELISA 18 to 30 days later, both viruses were detected. WMoV was detected in all 13 WCM-inoculated sweet corn plants and WSMV in two of them. Plants with WMoV alone initially had short chlorotic leaf streaks that subsequently combined, causing broad streaks. These are typical WMoV symptoms for sweet corn (1). No symptoms developed and no virus was detected in any of the uninoculated wheat or sweet corn control plants. The WMoV nucleotide sequence obtained from an infected sweet corn plant was identical to those of WA-CG12 and WA-KU12. To our knowledge, this is the first confirmed report of WMoV presence in Australia.

Soil and Phytosociological Characterisation of Grasslands in the Western Mediterranean

A study was made of grasslands in olive groves with a high frequency of Hordeum leporinum Link, Chrysanthemum coronarium L., Malva neglecta Wallr., Aegilops geniculata Roth and Dasypyrum villosum (L.) Borbas, initially included in the alliance Hordeion leporini Br.-Bl. in Br.-Bl., Gajewski, Wraber & Walas 1936 corr. O. Bolos 1962, and sub-alliance Malvenion neglectae Gutte 1966. The study was carried out in the western Mediterranean (Spain, Italy, Portugal and northern Morocco). The soil and phytosociological treatment of the samples contributes information for new plant communities. In the study of plant communities, the indices of degree of presence are adapted to those of Van der Maarel. The new alliance Securigero securidacae-Dasypyrion villosi is proposed for the sub-Mediterranean and Euro-Siberian territories, with the new communities Securigero securidacae-Dasypyretum villosi and Convolvulo elegantissimi-Aegilopetum geniculatae. This last community, due to its richness in Aegilops geniculata Roth, could be included in the alliance Taeniathero-Aegilopion geniculatae Rivas-Martinez & Izco 1977; however, the soil and statistical analyses reveal that it should remain part of the alliance Securigero securidacae-Dasypyrion villosi. The soil and floristic study of Hordeion leporini and Malvenion neglectae allows us to describe the new sub-alliance Resedo albae-Chrysanthemenion coronarii, subordinated to Malvion neglectae (Gutte 1966) status novo.

Chromosomal Characterization of the Three Subgenomes in the Polyploids of Hordeum murinum L.: New Insight into the Evolution of This Complex

Hordeum murinum L. is a species complex composed of related taxa, including the subspecies glaucum, murinum and leporinum. However, the phylogenetic relationships between the different taxa and their cytotypes, and the origin of the polyploid forms, remain points of controversy. The present work reports a comparative karyotype analysis of seven accessions of the H. murinum complex representing all subspecies and cytotypes. The karyotypes were determined by examining the distribution of the repetitive Triticeae DNA sequences pTa71, pTa794, pSc119.2, pAs1 and pHch950, the simple sequence repeats (SSRs) (AG)10, (AAC)5, (AAG)5, (ACT)5, (ATC)5, and (CCCTAAA)3 via in situ hybridization. The chromosomes of the three subgenomes involved in the polyploids were identified. All tetraploids of all subspecies shared the same two subgenomes (thus suggesting them to in fact belong to the same taxon), the result of hybridization between two diploid ancestors. One of the subgenomes present in all tetraploids of all subspecies was found to be very similar (though not identical) to the chromosome complement of the diploid glaucum. The hexaploid form of leporinum came about through a cross between a tetraploid and a third diploid form. Exclusively bivalent associations among homologous chromosomes were observed when analyzing pollen mother cells of tetraploid taxa. In conclusion, the present results identify all the individual chromosomes within the H. murinum complex, reveal its genome structure and phylogeny, and explain the appearance of the different cytotypes. Three cryptic species are proposed according to ploidy level that may deserve full taxonomic recognition.

Taxonomic revision of genus Hordeum L. (Gramineae) in Egypt

This study was conducted to revise the taxonomic identity and clarify inter- and intra-specific relationships among the studied wild and cultivated Hordeum taxa in Egypt. The studied taxa includedHordeum marinum subsp. gussoneanum, H. marinum subsp. marinum, H. Hordeum leporinum,Hordeum glaucum, Hordeum spontaneum and Hordeum vulgare. The results revealed that unweighted pair group method with arithmetic mean (UPGMA) dendrogram showed a considerable degree of dissimilarity among the studied Hordeum taxa at 1.50 dissimilarity distance. It divided the studied taxa into four groups at 1.33. Group 1 included H. marinum subsp. gussoneanum and H. marinum subsp.marinum. Group 2 included H. leporinum. Group 3 included H. glaucum. Group 4 included H.spontaneum and H. vulgare which is related to the other groups (1, 2, and 3). Moreover, by using UPGMA dendrogram, H. leporinum and H. glaucum are located in transitional position between H. marinum and both of H. vulgare and H. spontaneum forming a transitional step between the taxa of Group 1 and 4. This work provided a taxonomic key and separated the two subspecies of H. murinuminto different species namely H. glaucum and H. leporinum. Moreover, the morphological similarities among Hordeum taxa have been proved. Key words: Taxonomy, Hordeum marinum, Hordeum leporinum, Hordeum glaucum, Hordeum spontaneum, Hordeum vulgare, unweighted pair group method with arithmetic mean (UPGMA)dendrogram, Egypt.

The distribution of Russian Wheat Aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) in Turkey

The Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae), is one of the most economically important and widely distributed pests of wheat in the world. In 1962, D. noxia caused crop losses between 25 and 60% in the central province of Konya, Turkey. In this study, the current status of the pest in wheat-producing areas of Turkey was investigated along a route from Izmir to Manisa, Usak, Kutahya, Eskisehir, Aksehir, Ankara, Konya, Aksaray, Nevsehir, Yozgat and Erzurum. D. noxia was detected in 58 of the 100 wheat fields surveyed in most fields and wheat was at the heading stage. The population density of the pest was low in 23 fields, medium in 22 fields and high in 13 fields. The percentage of infestation was low in 31 fields, medium in 12 fields, and high in three fields and very high in three fields. D. noxia was collected from bread or durum wheat plants (71%), barley plants (10%), volunteer oats (8%) (Avena fatua), volunteer wheat (6%), false barley (Hordeum murinum) (4%) and natural grasses (1%). According to results of the study, population density, damage and infestation rates of D. noxia were higher in high altitudes.

Suitability of poaceous plants for nymphal growth of the pecky rice bugs Trigonotylus caelestialium and Stenotus rubrovittatus (Hemiptera: Miridae) in Niigata, Japan

Under laboratory conditions, we investigated the host suitability of 24 poaceous plants for Trigonotylus caelestialium (Kirkaldy) and Stenotus rubrovittatus (Matsumura). More than 50 % of the nymphs of both bugs reached the adult stage on Poa annua L., Alopecurus aequalis Sobol. var. amurensis (Komar.), Poa sphondylodes Trin., Hordeum murinum L., Agrostis clavata Trin. ssp. matsumurae (Hack. ex Honda), and Lolium multiflorum Lam. In addition, a similar number of S. rubrovittatus nymphs reached the adult stage on Dactylis glomerata L. and Digitaria violascens Link. However, a high percentage of T. caelestialium adults emerged on both spikelets and leaves of the host plants, whereas a lower percentage of S. rubrovittatus adults emerged on leaves than on spikelets. While the numbers of T. caelestialium adults that emerged on spikelets and leaves were similar, those reared on spikelets had a shorter developmental period and longer forewings than those reared on leaves, indicating that spikelets were more suitable for growth. In addition, more adults of both species emerged on plants with ears that arise during the spring and early summer than on plants with ears that arise during the summer and fall. Therefore, the development of these bugs is dependent on the season of ear emergence.

Host plant use for oviposition by Trigonotylus caelestialium (Hemiptera: Miridae) and Stenotus rubrovittatus (Hemiptera: Miridae)

The main hosts and sites of oviposition for the two bugs, Trigonotylus caelestialium (Kirkaldy) (Hemiptera: Miridae) and Stenotus rubrovittatus (Matsumura) (Hemiptera: Miridae), that cause pecky rice were investigated in 24 poaceous plants. Nymphs of T. caelestialium emerged from both spikelets and leaf sheaths, while nymphs of S. rubrovittatus emerged almost exclusively from spikelets. Suitable plants for oviposition by T. caelestialium are Lolium multiflorum, Digitaria violascens and Hordeum murinum, while Poa annua, Anthoxanthum odoratum, Alopecurus aequalis and D. violascens were preferentially used by S. rubrovittatus. There was a greater difference in the number of nymphs emerging from different plants for S. rubrovittatus than for T. caelestialium. This difference may be because T. caelestialium can oviposit on leaf sheaths if the spikelets are not suitable for oviposition, whereas S. rubrovittatus only oviposits on spikelets. Although both bugs oviposited on spikelets, the internal oviposition sites were different. In D. ciliaris, T. caelestialium laid all eggs between the lemma of the first floret and the second floret, whereas S. rubrovittatus laid eggs almost exclusively inside the second floret. In contrast, in P. annua, T. caelestialium laid all eggs inside the florets, whereas S. rubrovittatus laid eggs both between and inside the florets.

INTERACTIVE EFFECTS OF SALINITY AND PHOSPHORUS NUTRITION ON PHYSIOLOGICAL RESPONSES OF TWO BARLEY SPECIES

Salinity is one of the most important agricultural problems in Iran. The effect of different levels of salinity and phosphorus on shoot length, root and shoot fresh and dry weight, nutrient elements (sodium (Na+), potassium (K+), phosphorus (P) and chloride (Cl−), proline and soluble sugar contents of barley were investigated. Two cultivars of barley, Hordeum murinum (wild resistant germplasm) and Hordeum vulgar, variety Afzal were treated in vegetative stage under hydroponics condition in a factorial arrangement based on completely randomized block (CRB) design with four levels of salinity [0, 100, 200 and 300 mM sodium chloride (NaCl)] and three levels of phosphorus (15, 30 and 55 μm L−1) with three replications. By increasing salinity, all the measured parameters, except sodium (Na+) content were reduced. Furthermore, with increased in phosphorus levels from 15 to 55 μm, Na+ content of the plant shoots decreased, but length, fresh and dry weights of roots and shoots and K+, P, Cl−, proline, and soluble sugars content of the shoots increased. The results indicated that accumulation of mineral ions for osmotic adjustment and restriction of Na+ accumulation in shoots were involved in phosphorus enhancement of the salt tolerance of barley. Thus, it seems that in saline soils, where there is no possibility for soil leaching and amending, application of phosphorus fertilizers can lead to a satisfactory growth and production in barely yield.

Identification of resistance to either paraquat or ALS‐inhibiting herbicides in two Western Australian Hordeum leporinum biotypes

Hordeum populations are becoming increasingly difficult to control in cropping fields. Two herbicide-resistant H. leporinum populations were identified during a random crop survey after herbicides were applied. The study aimed to determine the herbicide resistance profile of these H. leporinum biotypes to a range of herbicides used for their control. Based on dose-response studies, one H. leporinum population was very highly resistant to sulfosulfuron and sulfometuron (both sulfonylurea herbicides) and also displayed low-level resistance to imazamox (an imidazolinone herbicide). Reduced sensitivity of the ALS enzyme was identified with in vitro activity assays. Gene sequence analysis revealed a proline-to-threonine substitution at amino acid position 197 of ALS, which is likely to be the molecular basis for resistance in this population. Herbicide screening also revealed a different H. leporinum population with resistance to the bipyridyl herbicide paraquat. This study established the first cases of (1) sulfonylurea-to-imidazolinone cross-resistance and (2) field-evolved paraquat resistance in a Hordeum species in Western Australia.

A Foreign Body Aspiration Showing Migration and Penetration: Hordeum Murinum

A Foreign Body Aspiration Showing Migration and Penetration: Hordeum Murinum

Assessment of genetic variation among fivehordeumspecies from Iran

In this study, simple sequence repeat (SSR) markers were used to investigate the genetic diversity and evolutionary relationships among 74 barley accessions; 15 landraces (Hordeum vulgare) and 59 wild accessions (twenty-one Hordeum spontaneum, ten Hordeum bulbosum, thirteen Hordeum murinum and fifteen Hordeum marinum). A total of 66 alleles were detected at 12 SSR loci, with an average of 5.5 alleles per locus in the entire samples. The average number of alleles (4.2) per locus was higher in H. vulgare and H. spontaneum, reflecting more genetic diversity within these two species compared with the other species. All index values of genetic diversity revealed that there was higher genetic diversity within H. vulgare landraces than within the wild species, indicating that cultivation unlikely to have caused a loss of genetic diversity in cultivated barley compared with its wild relatives. Analysis of molecular variance (AMOVA) revealed that 31% of the total observed variation was accounted for among species....

Arbuscular mycorrhizal fungal diversity in perennial pastures; responses to long-term lime application

We investigated the genetic diversity of arbuscular mycorrhizal fungi (AMF) in soils and the roots of Phalaris aquatica L., Trifolium subterraneum L., and Hordeum leporinum Link growing in limed and unlimed soil, the influence of lime application on AMF colonization and the relationship between AMF diversity and soil chemical properties. The sampling was conducted on a long-term liming experimental site, established in 1992, in which lime was applied every 6 years to maintain soil pH (in CaCl2) at 5.5 in the 0–10 cm soil depth. Polymerase chain reaction, cloning and sequencing techniques were used to investigate the diversity of AMF. Altogether, 438 AMF sequences from a total of 480 clones were obtained. Sequences of phylotypes Aca/Scu were detected exclusively in soil, while Glomus sp. (GlGr Ab) and an uncultured Glomus (UnGlGr A) were detected only in plant roots. Glomus mosseae (GlGr Aa) was the dominant AMF in the pastures examined; however, the proportion of G. mosseae was negatively correlated with soil pH, exchangeable Ca and available P. Generally, diversity of the AMF phylotypes was greater in the bulk unlimed soil and plants from this treatment when compared to the limed treatments. Long-term lime application changed soil nutrient availability and increased AMF colonization, but decreased AMF phylotype diversity, implying that soil chemistry may determine the distribution of AMF in acid soils. Future studies are required to explore the functions of these AMF groups and select the most efficient AMF for sustainable farming in acid soils.

Diversity and evolution of the Hordeum murinum polyploid complex in Algeria

Population diversity and evolutionary relationships in the Hordeum murinum L. polyploid complex were explored in contrasted bioclimatic conditions from Algeria. A multidisciplinary approach based on morphological, cytogenetic, and molecular data was conducted on a large population sampling. Distribution of diploids (subsp. glaucum) and tetraploids (subsp. leporinum) revealed a strong correlation with a North-South aridity gradient. Most cytotypes exhibit regular meiosis with variable irregularities in some tetraploid populations. Morphological analyses indicate no differentiation among taxa but high variability correlated with bioclimatic parameters. Two and three different nuclear sequences (gene coding for an unspliced genomic protein kinase domain) were isolated in tetraploid and hexaploid cytotypes, respectively, among which one was identical with that found in the diploid subsp. glaucum. The tetraploids (subsp. leporinum and subsp. murinum) do not exhibit additivity for 5S and 45S rDNA loci comparative with the number observed in the related diploid (subsp. glaucum). The subgenomes in the tetraploid taxa could not be differentiated using genomic in situ hybridization (GISH). Results support an allotetraploid origin for subsp. leporinum and subsp. murinum that derives from the diploid subsp. glaucum and another unidentified diploid parent. The hexaploid (subsp. leporinum) has an allohexaploid origin involving the two genomes present in the allotetraploids and another unidentified third diploid progenitor.

The use of microsatellite markers for genetic diversity assessment of genus Hordeum L. in Kerman province (Iran)

In this study, gene diversity and genetic relationships among 30 genotypes of genus Hordeum from Kerman province (Iran) were assessed using 10 simple sequence repeat (SSR) primers. Seven of these markers were highly polymorphic. A total of 96 alleles were detected. The number of alleles per microsatellite marker varied from 2 to 18. Except for Bmag0603, HVM36 and HvWAXY4, all the other markers showed on average, a high value of gene diversity ranging from 0.68 to 0.89. Primer GMS003 and GMS056 had the highest polymorphism information content (PIC) and so were able to distinguish different Hordeum genotypes. Cluster analysis based on unweighted pair group method with arithmetic averages (UPGMA) was accomplished by using the NTSYS-pc version 2.02 software for 4 major clusters which were finally extracted. Cluster 1 includes Hordeum distichon , Hordeum vulgare and Hordeum spontaneum , cluster 2 comprises Hordeum leporinum and Hordeum glaucum, cluster 3 has Hordeum bulbosum and cluster 4 includes Hordeum brevisubulatum ssp. iranicum . Data obtained from analysis are in complete agreement with taxonomic and gene pool classifications proposed previously. This study reports the first application of the SSR technique in characterization of genus Hordeum from Kerman province (Iran). Key words: Microsatellite markers, Hordeum , gene diversity, genetic relationships.

Characterizing Pathways of Invasive Plant Spread to Alaska: II. Propagules from Imported Hay and Straw

AbstractThe extent and nature of spread of exotic plant species to and within Alaska by shipment of hay and straw was studied. The amounts of hay and straw imported into Alaska and the amounts and types of seed in imported and locally produced hay and straw was determined We purchased alfalfa hay, wheat straw, ryegrass straw, and timothy hay produced in Washington and Oregon (WA–OR) and locally produced straw and hay. The hay and straw were shaken over screens, and the remaining fines were mixed with sterile potting soil and incubated in the greenhouse. Forty-nine plant species were identified from hay and straw, nine of which are ranked as invasive in Alaska, including downy brome, foxtail barley, hare barley, narrowleaf hawksbeard, and quackgrass—a prohibited weed in Alaska. The number of seeds ranged from 0 to 6,205 seeds kg−1, with an average of 585 seeds kg−1, and the number of species ranged from 0 to 12, with an average of 4.2 species per bale. Crop seed comprised a large proportion of the germinated seeds in ryegrass straw, wheat straw, and timothy/brome hay (98, 78, and 62%, respectively), but was less prevalent (ranging from 0 to 38%) in the other three hay and straw crop types. Hay and straw from Alaska contained more total seeds and species than hay and straw from WA-OR, but the difference was not significant when only weed seed was used in the analysis. Alaska-grown timothy/brome hay contained significantly more total seed than alfalfa hay and wheat straw from WA–OR and Alaska-grown barley straw. The grower or distributor of the hay and straw also influenced the number of seeds and species among some crop types. Results of this study document that large numbers of alien plant species are transported by movements of hay and straw into and within Alaska.

Analysis of DNA sequence polymorphism at the cMWG699 locus reveals phylogenetic relationships and allopolyploidy withinHordeum murinumsubspecies

Hordeum murinum L. is one of the most widely distributed species in the genus Hordeum. This species is composed of three subspecies with three ploidy levels, namely subsp. glaucum (2x=14), subsp. murinum (4x=28) and subsp. leporinum (4x=28, 6x=42). These three subspecies are morphologically similar and are frequently referred to as the 'murinum complex'. Although many cytological studies suggest that the murinum complex is allopolyploid, one inter-specific hybridization study suggested that it is autopolyploid. The goals of the present study are to identify nucleotide variation in the cMWG699 locus in the polyploid genomes of the murinum complex, to conduct molecular phylogenetic analysis of this locus, and to clarify the allo- versus auto-polyploidy status of the murinum complex. For this purpose, PCR-RFLP analysis was conducted with HhaI and SspI restriction enzymes on 80 H. murinum accessions. Single enzyme digestion data revealed polymorphism between diploid and polyploids, and double-digestion revealed polymorphism between tetra- and hexaploids. The nucleotide sequences of clones clearly show that polyploid murinum species are allopolyploid. In addition, DNA sequence analysis indicated that one donor of the tetraploid was subsp. glaucum (2x), as has been suggested previously by cytological studies. The other diploid donors were not identified, but at least one group of sequences common to 4x and 6x genomes (namely clonetype B) was highly diverged from 2x subsp. glaucum. The two tetraploid subspecies, 4x subsp. murinum and 4x subsp. leporinum, had identical DNA sequences, suggesting that these two subspecies are not differentiated at the cMWG699 locus.

Influence of finishing systems and sampling site on fatty acid composition and retail shelf-life of lamb

Thirty 7-month-old crossbred lambs (Poll Dorset × Border Leicester × Merino) finished over 5 weeks on either low quality pasture or grain-with-hay on a farm in southern Victoria were assessed for carcass parameters, muscle fat composition and retail colour stability. Lambs on the grain diet had a mix of barley grain (80%) and lentils (20%) at 800 g/head.day (air-dry basis ~ad libitum) with cape weed (Arctotheca calendula) hay available at all times. Lambs under grazing had predominantly rye grass (Lolium perenne) and barley grass (Hordeum leporinum) available ad libitum. Carcass weight tended to be higher (P = 0.14) in grain-fed lambs than in grass-fed lambs, but fatness indicated by GR (total muscle + fat tissue thickness at 11 cm from midline) did not differ between feeding systems. Fatty acid composition was determined in the loin from the forequarter (M. longissimus thoracis) and lumbar (M. longissimus lumborum) regions and from the leg region (M. semimembranosus). This showed that grain-finished lamb had higher muscle fat (P < 0.001) and omega-6 fatty acid (P < 0.001) content. Alpha-linolenic acid, eicosapentaenoic acid (EPA) or total omega-3 fat did not differ (P > 0.05) between feeding groups. Saturated fatty acids were greater (P < 0.01) in both loin sampling sites than the leg. The levels of EPA, docosahexaenoic acid and docosapentaenoic acid were lower (P < 0.01) in the forequarter (9%) or lumbar (11%) sites than the leg sampling site. The distribution pattern of fatty acids across the three sampling sites did not differ between feed types. Retail colour stability determined over 4 days of display (only performed in muscle from the lumbar site), evaluated by the redness (HunterLab a*-value) and metmyoglobin formation (reflectance ratio at 630 : 580-nm wavelengths) was superior for grass-fed lamb compared with short-term grain-finished lamb. The results demonstrate that the health claimable omega-3 fat mainly EPA or total omega-3 fat content in lamb was not altered by short-term grain finishing compared with lamb finished under pasture grazing conditions.

Two extinct diploid progenitors were involved in allopolyploid formation in the Hordeum murinum (Poaceae: Triticeae) taxon complex

Wall barley ( Hordeum murinum) occurs with three subspecies, naturally distributed from southern Central Asia through the Mediterranean region to northwestern Europe, but now is an invasive weed in many parts of the world. Subspecies glaucum is diploid, while subspp. murinum and leporinum are tetraploids, the latter also occurring with a hexaploid cytotype. Earlier analyses were inconclusive regarding auto- or allopolyploid origins of subspp. murinum and leporinum. We analyzed the phylogeny of the taxon group using amplified fragment length polymorphisms (AFLP), sequences of cloned PCR products of the nuclear ribosomal DNA internal transcribed spacer region (ITS), a part of the nuclear single-copy gene topoisomerase 6 (Topo6) spanning two introns, and sequences of the chloroplast trnL-F region together with length variation at six chloroplast microsatellite loci, including multiple individuals of each subspecies and cytotype, covering the entire natural distribution area of the species. Phylogenetic analyses with all used markers differentiate diploid and polyploids. Sequences of both nuclear regions indicated that diploid subsp. glaucum was involved in tetraploid formation together with a now extinct species belonging to the same Hordeum genome group (Xu). Furthermore, AFLP and ITS analyses suggest that a third, though closely related extinct taxon contributed to hexaploid formation. No method was able to discern tetraploid subspp. murinum and leporinum, which we attribute to the young age of subsp. murinum. None of the used molecular markers revealed a strong geographic pattern of genetic variation that would allow comprehensive phylogeographic analysis, most probably due to the very effective seed dispersal of the taxa.