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In northeast Mississippi, a native, cool-season grass component is needed for restoring and reclaiming grasslands and for providing quality forage for livestock. A field trial was established in Starkville, Mississippi, during fall 2010 to evaluate 18 entries of cool-season, perennial grasses (all Poaceae): 8 Elymus species including a Mississippi ecotype of southeastern wildrye ( Elymus glabriflorus (Vasey ex L.H. Dewey) Scribn. & C.R. Ball), orchardgrass ( Dactylis glomerata L.), tall fescue ( Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.), timothy ( Phleum pratense L.), and wheatgrass ( Thinopyrum intermedium (Host) Barkworth & D.R. Dewey) cultivars. The nonnative entries, specifically the orchardgrass and tall fescue cultivars, outperformed the native entries in height, dry matter yield, and ground cover ratings. Forage quality analysis, which included neutral detergent fiber, acid detergent fiber, and crude protein, however, indicated statistical similarities between Elymus species and domesticated, nonnative cultivars. Results from these experiments express the potential for improving agronomic characteristics in native germplasm for intensively managed grazing systems.

Two bread wheat lines each with a translocation on chromosome 7DL from either Thinopyrum intermedium (TC5 and TC14) or Thinopyrum ponticum (T4m), were hybridized in a ph1b mutant background to enhance recombination between the two translocated chromosomal segments. The frequency of recombinants was high in lines derived from the larger and similar-sized translocations (TC5/T4m), but much lower when derived from different-sized translocations (TC14/T4m). Recombinant translocations contained combinations of resistance genes Bdv2, Lr19 and Sr25 conferring resistance to Barley yellow dwarf virus (BYDV), leaf rust and stem rust, respectively. Their genetic composition was identified using bioassays and molecular markers specific for the two progenitor Thinopyrum species. This set of 7DL Th. ponticum/intermedium recombinant translocations was termed the Pontin series. In addition to Thinopyrum markers, the size of the translocation was estimated with the aid of wheat markers mapped on each of the 7DL deletion bins. Bioassays for BYDV, leaf rust and stem rust were performed under greenhouse and field conditions. Once separated from ph1b background, the Pontin recombinant translocations were stable and showed normal inheritance in successive backcrosses. The reported Pontin translocations integrate important resistance genes in a single linkage block which will allow simultaneous selection of disease resistance. Combinations of Bdv2 + Lr19 or Lr19 + Sr25 in both long and short translocations, are available to date. The smaller Pontins, comprising only 20 % of the distal portion of 7DL, will be most attractive to breeders.

Stripe rust, caused by Puccinia striiformis f. sp. tritici, was one of the most disaster foliar diseases for wheat-growing areas of the world. Thinopyrum intermedium has provided novel resistance genes to multi-fungal disease, and new wheat-Th. intermedium derivatives for stripe rust resistance still need to develop for wheat breeding. Wheat line X484-3 was selected from a cross between wheat line MY11 and wheat-Th. intermedium ssp. trichophorum partial amphiploid TE-1508, and was characterized by genomic in situ hybridization (GISH) and functional molecular markers. Chromosome counting revealed that the X484-3 was 2n = 44 and GISH analysis using Pseudoroegneria spicata genomic DNAas a probe demonstrated that X484-3 contained a pair of St-chromosomes from Th. intermedium donor parents. The functional molecular markers confirmed that introduced St-chromosomes belonging to linkage group 7, indicating that line X484-3 was a 7St addition line. The resistance observation displayed that the introduced Th. intermedium ssp. trichophorum derived chromosomes 7St were responsible for the stripe rust resistances at adult plant. The identified wheat-Th. intermedium chromosome 7St addition line X484-3 can be used as a donor in wheat breeding for stripe rust resistance.

The choice of plant materials is an important component of revegetation following disturbance. To determine the utility and effectiveness of various perennial grass species for revegetation on varied landscapes, a meta analysis was used to evaluate the stand establishment and persistence of 18 perennial cool-season grass species in 34 field studies in the Intermountain and Great Plains regions of the United States under monoculture conditions. Combined across the 34 studies, stand establishment values ranged from 79% to 43% and stand persistence values ranged from 70% to 0%. Intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth & D. R. Dewey), tall wheatgrass (Thinopyrum ponticum [Podp.] Z.-W. Liu & R.-C. Wang), crested wheatgrass (Agropyron spp.), Siberian wheatgrass (Agropyron fragile [Roth] P. Candargy), and meadow brome (Bromus riparius Rehmann) possessed the highest stand establishment (≥ 69%). There were no significant differences among the 12 species with the largest stand persi...

Thinopyrum intermedium has been hybridized extensively with wheat (Triticum aestivum L.) and several genes for disease resistance have been introgressed to cultivated wheat. However, there are very few reports about the Th. intermedium-derived seed storage protein genes which have been transferred into a wheat background by chromosome manipulation. Our aim is to identify several wheat–Th. intermedium ssp. trichophorum derivatives, and document these lines by genomic in situ hybridization (GISH), molecular markers and seed storage protein analysis. We found that a novel Th. intermedium 1St#2 chromosome-specific high-molecular-weight glutenin subunit (HMW-GS) was transferred to the wheat–Thinopyrum derivative lines. The genomic sequence of the Thinopyrum-derived HMW-GS was characterized and designated Glu-1St#2x, since it resembled x-type glutenins in both the N-terminal domain and C-terminal domain. It is much shorter than that of reported HMW-GS genes. The Glu-1St#2x sequence was successfully expressed in Escherichia coli and resulted in the identical weight to the native protein. The GISH and newly developed chromosome Thinopyrum-specific DNA markers enabled physically location of Glu-1St#2x to the region FL0.60–1.00 on Th. intermedium 1St#2L chromosome arm. Phylogenetic analysis revealed that the Glu-1St#2x evolved earlier than other x-type HMW-GS homoeologues in modern wheat genomes. The effect of Glu-1St#2x on protein content, sodium dodecyl sulphate sedimentation value and improvement of solvent retention capacity in wheat background suggested that Th. intermedium chromosome 1St#2 may have potential for improvement of wheat end-product quality.

Thinopyrum intermedium, a wild relative of wheat, is an excellent source of disease resistance. Two novel partial amphiploids, 08-47-50 and 08-53-55 (2n = 6x = 42), were developed from wide crosses between durum wheat and Th. intermedium. Meiotic analysis showed that pollen mother cells of the two partial amphiploids formed an average 20.49 bivalents for 08-47-50 and 20.67 bivalents for 08-53-55, indicating that they are basically cytologically stable. GISH analysis revealed that the two partial amphiploids carried different chromosome compositions. 08-47-50 had fourteen chromosomes from Th. intermedium and its alien chromosomes included six St-, four E(e) - and four E(e)-St translocated chromosomes, whereas 08-53-55 had four St- and ten E(e)-St translocated chromosomes. Fungal disease evaluation indicated that both partial amphiploids had a high level of resistance to FHB, leaf rust and stem rust race Ug99. These two novel partial amphiploids with multiple disease resistance could be used as a new source of multiple disease resistance in bread wheat and durum wheat breeding programs.

The emergence of the highly virulent Ug99 race complex of the stem rust fungus (Puccinia graminis Pers. f. sp. tritici Eriks. and Henn.) threatens wheat (Triticum aestivum L.) production worldwide. One of the effective genes against the Ug99 race complex is Sr44, which was derived from Thinopyrum intermedium (Host) Barkworth and D.R. Dewey and mapped to the short arm of 7J (designated 7J#1S) present in the noncompensating T7DS-7J#1L∙7J#1S translocation. Noncompensating wheat-alien translocations are known to cause genomic duplications and deficiencies leading to poor agronomic performance, precluding their direct use in wheat improvement. The present study was initiated to produce compensating wheat-Th. intermedium Robertsonian translocations with Sr44 resistance. One compensating RobT was identified consisting of the wheat 7DL arm translocated to the Th. intermedium 7J#1S arm resulting in T7DL∙7J#1S. The T7DL∙7J#1S stock was designated as TA5657. The 7DL∙7J#1S stock carries Sr44 and has resistance to the Ug99 race complex. This compensating RobT with Sr44 resistance may be useful in wheat improvement. In addition, we identified an unnamed stem rust resistance gene located on the 7J#1L arm that confers resistance not only to Ug99, but also to race TRTTF, which is virulent to Sr44. However, the action of the second gene can be modified by the presence of suppressors in the recipient wheat cultivars.

Thinopyrum intermedium is a useful source of resistance genes for Barley Yellow Dwarf Virus (BYDV), one of the most damaging wheat diseases. In this study, wheat/Th. intermedium translocation lines with a BYDV resistance gene were developed using the Th. intermedium 7Ai-1 chromosome. Genomic in situ hybridization (GISH), using a Th. intermedium total genomic DNA probe, enabled detection of 7Ai-1-derived small chromatins containing a BYDV resistance gene, which were translocated onto the end of wheat chromosomes in the lines Y95011 and Y960843. Random amplified polymorphic DNA (RAPD) analyses using 120 random 10-mer primers were conducted to compare the BYDVresistant translocation lines with susceptible lines. Two primers amplified the DNA fragments specific to the resistant line that would be useful as molecular markers to identify 7Ai-1-derived BYDV resistance chromatin in the wheat genome. Additionally, the isolated Th. intermedium-specific retrotransposon-like sequence pTi28 can be used to identify Th. intermedium chromatin transferred to the wheat genome. Thinopyrum intermedium является полезным источником генов устойчивости к вирусу желтой карликовости ячменя (BYDV), одного из наиболее серьезных заболеваний пшеницы. В настоящей работе транслокационные линии пшеница/Th. intermedium с геном устойчивости BYDV получены с использованием 7Ai-1 хромосомы Th. intermedium. Геномная гибридизация in situ (GISH) с использованием тотальной ДНК Th. intermedium в качестве зонда дала возможность показать наличие небольшого фрагмента хромосомы, происходящего от хромосомы 7Ai-1 и содержащего ген устойчивости BYDV, который транслоцировался в терминальний участок одной из пшеничных хромосом в каждой из линий Y95011 и Y960843. RAPD-анализ был проведен с использованием 120 случайных 10-нуклеотидных праймеров для сравнения BYDV-устойчивых транслокационных линий с восприимчивыми линиями. Два праймера амплифицировали фрагменты ДНК, специфичные для устойчивой линии, и они могут быть использованы как молекулярные маркеры для идентификации в геноме пшеницы хроматина, транслоцированного от 7Ai-1. Кроме того, выделенная Th. intermedium-специфичная ретротранспозон-подобная последовательность pTi28 может быть использована для идентификации хроматина Th. intermedium, перенесенного в геном пшеницы.

Development of perennial grains is being promoted to aid in moving agriculture towards sustainable production. How long does it take to identify perennial yielding ability? Intermediate wheatgrass [Thinopyrum intermedium (Host) Bark. & Dewey] nurseries were transplanted in 2011 (4500 plants) and 2012 (1000 plants) at Carman, MB. Productive, healthy plants were harvested on a yearly basis. Intolerance to late frosts after spring regrowth initiation in 2012 (approximately 55% of the plants) and in 2014 (the entire 2012 nursery) led to these plants not being harvested. Mean yield plant−1 was 37.25, 66.70, and 57.81 g for the 2012, 2013, and 2014 overall harvests, respectively. Individual plants showed divergent seed yielding patterns across years, especially with respect to the third harvest year. A number of plants were identified that had consistent relative seed yields over the 3 yr of harvest for the 2011 nursery. Linear regression indicated that the first year of seed production was a poor indicator of ...

Fluorescence in situ hybridization and molecular markers have confirmed that several chromosomes from Thinopyrum intermedium ssp. trichophorum have been added to a wheat background, which originated from a cross between a wheat– Thinopyrum partial amphiploid and triticale. The lines displayed blue grains and resistance to wheat stripe rust. Thinopyrum intermedium has been used as a valuable resource for improving the disease resistance and yield potential of wheat. With the aim to transfer novel genetic variation from Th. intermedium species for sustainable wheat breeding, a new trigeneric hybrid was produced by crossing an octoploid wheat–Th. intermedium ssp. trichophorum partial amphiploid with hexaploid triticale. Fluorescence in situ hybridization (FISH) revealed that Thinopyrum chromosomes were transmitted preferably and the number of rye chromosomes tended to decrease gradually in the selfed derivatives of the trigeneric hybrids. Four stable wheat–Th. intermedium chromosome substitution, addition and translocation lines were selected, and a 2JS addition line, two substitution lines of 4JS(4B) and 4J(4B), and a small 4J.4B translocation line were identified by FISH and molecular markers. It was revealed that the gene(s) responsible for blue grains may located on the FL0.60–1.00 of long arm of Th. intermedium-derived 4J chromosome. Disease resistance screenings indicated that chromosomes 4JS and 2JS appear to enhance the resistance to stripe rust in the adult plant stage. The new germplasm with Th. intermedium introgression shows promise for utilization of Thinopyrum chromosome segments in future wheat improvement.

This paper reports detailed FISH-based karyotypes for three diploid wheatgrass species Agropyron cristatum (L.) Beauv., Thinopyrum bessarabicum (Savul.&Rayss) A. Love, Pseudoroegneria spicata (Pursh) A. Love, the supposed ancestors of hexaploid Thinopyrum intermedium (Host) Barkworth & D.R.Dewey, compiled using DNA repeats and comparative genome analysis based on COS markers. Fluorescence in situ hybridization (FISH) with repetitive DNA probes proved suitable for the identification of individual chromosomes in the diploid JJ, StSt and PP genomes. Of the seven microsatellite markers tested only the (GAA)n trinucleotide sequence was appropriate for use as a single chromosome marker for the P. spicata AS chromosome. Based on COS marker analysis, the phylogenetic relationship between diploid wheatgrasses and the hexaploid bread wheat genomes was established. These findings confirmed that the J and E genomes are in neighbouring clusters.

Here, we report the production of a wheat- Thinopyrum intermedium recombinant stock conferring resistance to wheat streak mosaic virus and Triticum mosaic virus. Wheat streak mosaic caused by the wheat streak mosaic virus (WSMV) is an important disease of bread wheat (Triticum aestivum) worldwide. To date, only three genes conferring resistance to WSMV have been named and two, Wsm1 and Wsm3, were derived from the distantly related wild relative Thinopyrum intermedium. Wsm3 is only available in the form of a compensating wheat-Th. intermedium whole-arm Robertsonian translocation T7BS·7S#3L. Whole-arm alien transfers usually suffer from linkage drag, which prevents their use in cultivar improvement. Here, we report ph1b-induced homoeologous recombination to shorten the Th. intermedium segment and recover a recombinant chromosome consisting of the short arm of wheat chromosome 7B, part of the long arm of 7B, and the distal 43% of the long arm derived from the Th. intermedium chromosome arm 7S#3L. The recombinant chromosome T7BS·7BL-7S#3L confers resistance to WSMV at 18 and 24 °C and also confers resistance to Triticum mosaic virus, but only at 18 °C. Wsm3 is the only gene conferring resistance to WSMV at a high temperature level of 24 °C. We also developed a user-friendly molecular marker that will allow to monitor the transfer of Wsm3 in breeding programs. Wsm3 is presently being transferred to adapted hard red winter wheat cultivars and can be used directly in wheat improvement.

Development of the first consensus genetic map of intermediate wheatgrass gives insight into the genome and tools for molecular breeding. Intermediate wheatgrass (Thinopyrum intermedium) has been identified as a candidate for domestication and improvement as a perennial grain, forage, and biofuel crop and is actively being improved by several breeding programs. To accelerate this process using genomics-assisted breeding, efficient genotyping methods and genetic marker reference maps are needed. We present here the first consensus genetic map for intermediate wheatgrass (IWG), which confirms the species’ allohexaploid nature (2n = 6x = 42) and homology to Triticeae genomes. Genotyping-by-sequencing was used to identify markers that fit expected segregation ratios and construct genetic maps for 13 heterogeneous parents of seven full-sib families. These maps were then integrated using a linear programming method to produce a consensus map with 21 linkage groups containing 10,029 markers, 3601 of which were present in at least two populations. Each of the 21 linkage groups contained between 237 and 683 markers, cumulatively covering 5061 cM (2891 cM––Kosambi) with an average distance of 0.5 cM between each pair of markers. Through mapping the sequence tags to the diploid (2n = 2x = 14) barley reference genome, we observed high colinearity and synteny between these genomes, with three homoeologous IWG chromosomes corresponding to each of the seven barley chromosomes, and mapped translocations that are known in the Triticeae. The consensus map is a valuable tool for wheat breeders to map important disease-resistance genes within intermediate wheatgrass. These genomic tools can help lead to rapid improvement of IWG and development of high-yielding cultivars of this perennial grain that would facilitate the sustainable intensification of agricultural systems.

Genomic in situ hybridization and fluorescence in situ hybridization were used to define the cytogenetic constitution of the intergeneric introgression line 29(1-57) obtained from the wheat × Thinopyrum intermedium (wheatgrass) cross. This line is a high-protein line resistant to leaf rust, yellow rust, and powdery mildew under field conditions and has 42 chromosomes. GISH analysis using a total genomic DNA probe from Thinopyrum intermedium resulted in the identification of 14 chromosomes of wheatgrass origin. The sequential GISH patterns obtained using St-genomic and J-genomic DNA as probes and ABD-genomic DNA from wheat as a blocker led to a better determination of the genomic type of wheatgrass chromosomes. Rearrangements involving Thinopyrum chromosomes and the A, B, and D genomes of wheat were not observed. FISH using the repetitive DNA probes pSc119.2, Afa-family, and pTa71 allowed for identification of all the wheat chromosomes present.

This study evaluated over 150 wheat x wheatgrass derivatives in a series of field experiments. The objective was to assess their capacity to regrow post-harvest and yield grain over successive years, and thereby identify characteristics common to the surviving breeding lines. Over the 3-year experimental period 61% of the 176 experimental entries demonstrated some capacity for post-harvest regrowth. Of 125 entries planted in the first two years of experimentation, 34% persisted to produce a second grain harvest in year 2. Three entries from 73 planted in 2008 persisted to produce grain in 3 successive years. In a subset of 87 entries that underwent cytogenetic analysis there was an association between regrowth ability and the presence of at least one whole genome equivalent (14 chromosomes) from the perennial donor species. If the wheat parent was a hexaploid (2n = 42), an entry required at least 56 chromosomes to achieve any substantial post-harvest regrowth. However, the presence of 56 chromosomes was no guarantee of a capacity to survive post-harvest. The morphology of the hybrid germplasm was highly variable for every trait assessed including grain yield, grain size, grain quality, harvest index, tiller height and head morphology; reflective of the diversity of pedigrees. Narrower kernels appeared to be associated with higher grain protein concentrations. Unextractable polymeric protein (UPP) correlates with rheological properties of the doughs; some of the experimental entries had very low UPP; the majority had high UPP suggesting useful flour, dough and baking properties. A high level of disease resistance was observed in the subset of entries tested for leaf, stem and stripe rust as well as wheat streak mosaic virus, indicating that further development of hybrid germplasm would be unlikely to pose an unacceptable disease threat to conventional cereal crops, particularly where amphiploids were deployed. The variability of the cohort and the presence of entries with desirable agronomic and grain quality attributes suggested a potential to breed and select for perennial wheat derivatives with commercially desirable characteristics. (C) 2012 Elsevier B.V. All rights reserved.

Thinopyrum intermedium is an important species with potential utilization value in breeding of wheat. In this study, the non-coding intergenic region of trnH-psbA was investigated to assess the genetic diversity and infer the maternal origin within T. intermedium accessions. Eleven haplotypes were distinguished among the thirty-five accessions of T. intermedium. They showed a relatively low nucleotide diversity (π) of 0.00473 ± 0.00037 and a moderately high haplotype diversity (Hd) of 0.733 ± 0.061. In the phylogenetic analysis, all accessions of T. intermedium were positioned into two clades, which corresponded to the different diploid donors. These results suggested that there were two phylogenetically divergent maternal donors in T. intermedium.

Cereal cyst nematode (CCN) is becoming one of the important soil-borne pathogens in wheat (Triticum aestivum L.) monocropping or wheat- maize (Zea mays L.)-wheat cropping systems of central China. Heterodera fi lipjevi (Madzhidov, 1981) Stelter, 1984 was recently recognized as a causal agent of CCN in China, but little informa- tion is available on sources of resistance against this nematode species. The present study was initiated to determine the current status of resis- tance in wheat cultivars against H. fi lipjevi and to identify effective resources for improvement of CCN resistance in China. A 3-yr fi eld study of CCN resistance that involved 174 wheat cul- tivars or wheat-Thinopyrum derivatives was conducted in a wheat fi eld in Xuchang, Henan Province, China, where H. fi lipjevi had been present for years. Greenhouse experiments were conducted with representative resistant entries from each group of accessions. None of the 78 wheat cultivars and breeding lines from China was resistant in fi eld tests. Wheat cultivar Madsen from Washington State was most resis- tant among the entries tested both in fi eld and under controlled environment. New sources of resistance to H. fi lipjevi were identifi ed in some wheat-intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D. R. Dewey) and wheat-tall wheatgrass (Thinopyrum ponti- cum (Podp.) Barkworth & D. R. Dewey) partial amphiploids, which will diversify resistance resources in enhancing resistance of wheat against CCN.

Calcium (Ca) and nitrogen (N) treatments (2, 8, and 32 mg L−1) were investigated on aboveground and belowground growth of switchgrass (Panicum virgatum L.) and intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] in a greenhouse experiment. Switchgrass (cultivars ‘Sunburst’ and ‘Dacotah’), and intermediate wheatgrass (cultivar ‘Reliant’) aboveground and belowground biomass were harvested and analyzed to determine total biomass, macronutrient concentrations, and forage quality. Intermediate wheatgrass biomass followed a positive response to increasing N and Ca while switchgrass response to N and Ca treatments varied by cultivar. Increased Ca supplementation rates from 2 mg L to 32 mg L−1 increased aboveground Ca concentrations of 113% and 257% for switchgrass and intermediate wheatgrass, respectively. Calcium had little impact on measured cell wall characteristics with the exception of hemicellulose content in intermediate wheatgrass. Further investigation on intermediate wheatgra...

Wheat streak mosaic virus (WSMV) has been newly documented in Australia. The vulnerability of contemporary Australian elite wheat germplasm prompted a survey for effective resistance against an Australian isolate, WSMV-ACT. This study confirms the effectiveness of previously reported sources of resistance and shows that new sources of resistance also confer protection. The resistance derived from Thinopyrum intermedium (Wsm1) as a 4D translocation and a new 4A translocation, and two bread wheat resistances, Wsm2 and the new source c2652, were effective against WSMV-ACT in glasshouse experiments. Wsm1 was effective at lower temperatures but ineffective above 20°C, a temperature sensitivity shared with many of the derivatives of Wsm2 except for one new selection which was effective at 26°C. True wheats c2652 and Wsm2 selection CA745, and amphiploids Zhong1, Zhong2, Zhong4, Zhong5, TAF46, Summer1, Ot38 and OK7211542 were uniformly resistant at 20, 25 and 28°C. New sources of resistance were identified in a Th. scirpeum-wheat amphiploid, B84-994, and in chromosome addition lines Z2, Z6 and TAi27, derived from wheat-Th. intermedium partial amphiploids. Several new, tightly linked SSR, RAPD and EST-ILP PCR markers were developed for tracking the various Th. intermedium translocations associated with Wsm1, including the smaller translocations on wheat chromosome 4AS and 4DS. Three markers for the 4A-Wsm1 translocation were validated on a segregating breeding population.

Segregation distortion can be defined as deviations from normal Mendelian segregation (Sandler et al. 1958). It is a common phenomenon found in most genetic mapping studies in many species (Faris et al. 1998). Lophopyrum ponticum (also syn. Agropyron elongatum (Host) Beau.) has been one of the most important perennial Triticeae germplasm sources for wheat improvement (Oliver et al. 2006). Chromosome 7E of L. ponticum is crucial because it is the carrier of a number of elite agronomic traits (Zhang et al. 2011). However, there is still no report about molecular markers showing segregation distortion region of L. ponticum chromosome 7E. Segregation distortion caused by preferential transmission may be affected by genetic background. Kong et al. (2008) reported that a segment of the Thinopyrum intermedium chromosome 7E present in the translocation line P98134 was preferentially transmitted through male gametes under different genetic background conditions. However, the transmission frequency of T. intermedium 7E segment present in another wheat T. intermedium translocation line, P961341, varied with different genetic backgrounds. Similarly, studies on the translocations involving T. ponticum chromosome 7el1 indicated that Thinopyrum chromosome 7el1 was transmitted normally in Thatcher and China Spring wheat backgrounds (McIntosh et al. 1976). However, high levels of distortion were observed when chromosome 7el1 was transferred in other genetic backgrounds (McIntosh et al. 1995). Both 7el1 and 7el2, are gametocidal chromosomes (KibirigeSebunya and Knott 1983; Prins et al. 1996). Gametocidal chromosomes cause abortion of gametes lacking the gametocidal chromosome, which results in partial sterility and exclusive transmission of these chromosomes (Endo 1990).

Fluorescence and genomic in situ hybridization (FISH and GISH) were used to establish the cytogenetic constitution of two wheat × Thinopyrum intermedium partial amphiploids H95 and 55(1-57). Both partial amphiploids are high-protein lines having resistance to leaf rust, yellow rust and powdery mildew and have in total 56 chromosomes per cell. Repetitive DNA probes (pTa71, Afa family and pSc119.2) were used to identify the individual wheat chromosomes and to reveal the distribution of these probes within the alien chromosomes. FISH detected 6B tetrasomy in H95 and a null (1D)-tetrasomy (1B) in 55(1-57). GISH was carried out using biotin labeled Th. intermedium DNA and digoxigenin labeled Pseudoroegneria spicata DNA as probes, subsequently. GISH results revealed 44 wheat chromosomes and four Thinopyrum chromosome pairs, including three S and one J chromosome pairs in line H95. Line 55(1-57), contained 42 wheat chromosomes and six Th. intermedium pairs, including two S and one J(S) pairs. Additionally, two identical translocated chromosome pairs with diminished affinity to the alien chromatin were detected in both amphiploids. Another two translocations were found in 55(1-57), with satellite sections from the Thinopyrum J genome.

High molecular weight (HMW) glutenin subunits (GSs) play an important role in determining end-use quality in wheat (Triticum aestivum L.). They are also excellent protein markers for genotype identification. In this study, we analyzed the HMW-GSs in Thinopyrum bessarabicum (Savul. and Rayss) A. Love, Th. intermedium (Host) Bark-worth and D.R. Dewey, Lophopyrum elongatum (Host) A. Love, and A. markgrafii (Greuter) Hammer and genotyped eight sets of 44 disomic addition lines derived from these species in common wheat or durum wheat background using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and urea/SDS-PAGE. A total of 20 unique alleles for HMW-GSs were identified from the alien species. Among the eight sets of addition lines, only four addition lines carried the HMW-GSs derived from alien species. In the wheat-Th, intermedium chromosome 1Ai addition line TA3649, the HMW-GSs encoded by Glu-D1 were not expressed while the alien HMW-GSs were present, indicating that the Glu-D1 locus might be lost or the alien chromosomes might have silenced the expression of the Glu-D1 alleles. The wheat-Th, intermedium chromosome 7Ai long arm ditelosomic addition line, TA3659, carried two sets of HMW-GSs (1Dx4+1Dy12 and 1Dx5+1Dy10) encoded by the Glu-D1 locus. The results in this study also provided information on the alien chromosome donors and wheat parents for some disomic addition lines. Such information is useful for the development of molecular markers that will facilitate the introgression of desirable genes from the alien chromosomes into wheat genomes. The identified novel HMWGS alleles may serve as new genetic resources for wheat quality improvement.

Partial amphiploids between wheat (Triticum aestivum L.) and Thinopyrum species play an important role in the transfer and use of traits from alien species. A wheat-Thinopyrum intermedium partial amphiploid, TAI8335, and its alien parent were characterized by a combination of genomic in situ hybridization (GISH) and cytological observations. Evidence from GISH indicated that the donor parent Th. intermedium possessed seven pairs of S, seven J(s) and 21 J chromosomes. Mitotic observation showed that the majority of TAI8335 plants had 56 chromosomes, but a few had 54 to 55, in some cases with two to three additional telochromosomes. The chromosomes in most pollen mother cells of plants with 2n = 56 formed 28 bivalents, averaging 27.12 in 223 cells, suggesting a basic cytological stability. Sequential GISH patterns using genomic Pseudoroegneria spicata and genomic Th. intermedium DNA as probes revealed that TAI8335 had fourteen chromosomes derived from Th. intermedium and its alien genome consisted of one pair of S-, three pairs of J(s) - and one pair of J-genome chromosomes as well as two translocated chromosome pairs, one being a Robertsonian translocation and another an intercalary translocation, both of which involved J and S genome. Two of the telochromosomes in the aneuploid plants originated from the J genome and one from wheat. Disease screening demonstrated this line was highly resistant to leaf rust, stem rust, stripe rust and powdery mildew. This study showed that the partial amphiploid TAI8335 appears to serve as a novel source for the transfer of resistance genes for multiple fungal pathogens to wheat.

Winter wheat (Triticum aestivum L.) pastures are a primary source of cool-season forage used by stocker cattle (Bos taurus L.) in the southern Great Plains. Replacing some wheat pasture with perennial cool-season grasses (PCSGs) could reduce uncertainties of sufficient fall forage and annual tillage operations. Wheat forage is capable of producing stocker weight gains >1.4 kg d -1 , but wheat can accumulate nitrate that poses a health risk to stockers. Levels of crude protein (CP) and nitrate in fall forage clipped 4 yr (2002-2005), from replicated pastures of winter wheat and two PCSG pastures established in 2001 ('Jose' tall wheatgrass [Thinopyrum ponticum (Podp.) Z.-W. Liu & R.-C. Wang], 'Manska' intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & D.R. Dewey], and one PCSG pasture established in 2002 ['Lincoln' smooth bromegrass (Bromus inermis Leyss)], were compared. Forage levels of CP in PCSGs were >148 g kg -1 dry wt., but were 21 to 37% less than that of wheat (244 ± 3 g kg -1 ). Mean nitrate-N levels of wheat were 400, 1400, 4600, and 840 mg kg -1 in 2002 through 2005, respectively. Among the PCSGs, nitrate-N did not exceed 660 mg kg -1 . The CP levels of PCSGs were often substantially less than that of wheat, but were sufficient for growth of stocker calves. Nitrate risks that sometimes occurred with wheat would make PCSGs a safer choice for pasture.

Rhizomes facilitate the wintering and vegetative propagation of many perennial grasses. Sorghum halepense (johnsongrass) is an aggressive perennial grass that relies on a robust rhizome system to persist through winters and reproduce asexually from its rootstock nodes. This study aimed to sequence and assemble expressed transcripts within the johnsongrass rhizome. A de novo transcriptome assembly was generated from a single johnsongrass rhizome meristem tissue sample. A total of 141,176 probable protein‐coding sequences from the assembly were identified and assigned gene ontology terms using Blast2GO. Estimated expression analysis and BLAST results were used to reduce the assembly to 64,447 high‐confidence sequences. The johnsongrass assembly was compared to Sorghum bicolor, a related nonrhizomatous species, along with an assembly of similar rhizome tissue from the perennial grain crop Thinopyrum intermedium. The presence/absence analysis yielded a set of 98 expressed johnsongrass contigs that are likely associated with rhizome development.

Wheat stripe rust (Puccinia striiforis f. sp. tritici) races CYR31 and CYR32, prevalent in China, are virulent to many wheat stripe rust resistance genes (Yr genes). To expand the availability of effective resistance to CYR31 and CYR32, stripe rust resistance was transferred from intermediate wheatgrass (Thinopyrum intermedium) to common wheat (Triticum aestivum). The susceptible wheat cultivar CM107 was crossed with amphiploid TAI7047, derived from the wide cross Taiyuan768/Thinopyrum intermedium//76(64). Two wheat lines originating from the cross, YU24 and YU25, were resistant to CYR31 and CYR32. Pedigree analysis showed that the resistance to stripe rust in YU24 and YU25 originated from intermediate wheatgrass. Genetic analyses indicated that the resistance to stripe rust is controlled by a single dominant gene. Allelic tests determined that the resistance gene(s) in YU24 and YU25 are identical. The new gene has temporarily been designated as YrYU25. SSR and RAPD analyses showed that YrYU25 was introduced by cryptic translocation into common wheat., Les races CYR31 et CYR32 de la rouille jaune du blé (Puccinia striiforis f. sp. tritici), très répandues en Chine, sont virulentes pour plusieurs gènes de résistance à cette maladie (gènes Yr). Afin d'accroître la disponibilité d'une résistance efficace aux races CYR31 et CYR32, la résistance à la rouille jaune du blé a été transférée de l'agropyre intermédiaire (Thinopyrum intermedium) au blé tendre (Triticum aestivum). CM107, un cultivar de blé sensible, a été croisé avec l'amphiploïde AI7047 dérivé du croisement éloigné Taiyuan768/Thinopyrum intermedium//76(64). Deux lignées de blé provenant de ce croisement, soit YU24 et YU25, étaient résistantes aux races CYR31 et CYR32. Une analyse généalogique a démontré que la résistance à la rouille jaune du blé chez les lignées YU24 et YU25 provenait de l'agropyre intermédiaire. Des analyses génétiques ont indiqué que cette résistance était contrôlée par un seul gène dominant. Des tests d'allélisme ont révélé que le(s) gène(s) de résistance dans les lignées YU24 et YU25 étaient identiques. Le nouveau gène a temporairement été nommé YrYU25. Des analyses SSR et RAPD ont démontré que le gène YrYU25 avait été introduit dans le blé tendre par translocation cryptique.

Grass lodging is a major problem that can result in crop failure in grass seed production. An anti-gibberellic acid, prohexadione-Ca, was tested at 0, 14, 21, 28, and 42 oz of Apogee (BASF, Port Arthur, TX) per acre to prevent lodging in established irrigated intermediate (Thinopyrum intermedium) and western (Pascopyrum smithii) wheatgrass in the Nebraska Panhandle. In 2005, weather conditions in June and July were conducive to lodging. Prohexadione-Ca reduced lodging from 65% to less than 10%. In 2006, warmer temperatures (1.9°F above normal) and less rainfall (1.6 inch) in June and July reduced heights of both species, and lodging did not occur. In both years, prohexadione-Ca shortened head length of intermediate wheatgrass by 10% but increased head length by 10% in western wheatgrass. Grain yield averaged 250 lb/acre and 112 lb/acre over two years for intermediate and western wheatgrass, respectively, and seed germination averaged 96% and 85%. Seed yield and viability were not significantly affected by prohexadione-Ca. When good growing conditions are present in June, lodging of wheatgrass may become a serious problem and application of prohexadione-Ca (Apogee) at labeled rates is recommended as a preventative measure. Introduction Currently intermediate wheatgrass seed costs between about $25 and $45/acre at $2.50 to $3/lb seeded at 10 to 15 lb/acre. Western wheatgrass seed costing about $5 to $6/lb and seeded at the same rate would cost between $50 and $90/acre (Dan Laursen, cooperating grower, personal communication). A major contributing factor to this cost is lodging of wheatgrass grown under intensive management practices. Lodging may be so severe as to result in a total crop loss. Intensive management practices that promote seed production and lodging are high nitrogen input and irrigation (9). Preventing or greatly reducing lodging would increase cost efficiency and allow wheatgrass seed production under intensive management. Lodging is associated with longer stem length which is promoted by internally produced gibberellic acid (GA ), a natural plant hormone (2,6,13). Therefore, an approach to reduce lodging potential is to use an anti-GA such as prohexadione-Ca, a relatively new antiGA (8). Another anti-GA , chlormequat chloride, has been used successfully throughout the world to inhibit lodging of wheat (4,10) and rice (7). Although prohexadione and chlormequat are anti-GA compounds, their structures are very dissimilar. Their charges are opposite with prohexadione as an anion and chlormequat as a cation explaining why one is salified with Ca and the other with Cl in their formulation. Ethephon is another chemical used as an antilodging agent but its mode of action is to release ethylene (10). The objective of this study was to determine whether prohexadione-Ca would reduce the height and lodging of intermediate and western wheatgrass grown under irrigation and with nitrogen fertilization over two consecutive years. 3

Yellow dwarf (YD) disease is one of the most destructive diseases of cereals worldwide. Wheat (Triticum aestivum L.)-Thinopyrum intermedium 7E(7D) substitution line P29 carries resistance to YD, known as Bdv3, that originates on the long arm of chromosome 7E of Th. intermedium, and the resistance was introgressed into wheat chromosome 7D as T7DS.7DL-7EL in the translocation lines P961341 and P98134. Until now, quantification of YD viruses in cereal crops was usually done by enzyme-linked immunosorbent assay (ELISA), which is time consuming and laborious. To facilitate this analysis, SSR-Bdv3, a diagnostic molecular marker, was developed in this study. The transmission of the Th. intermedium segment with Bdv3 was investigated using the SSR-Bdv3 marker and ELISA in F 2 and testcross progeny derived by crossing two wheat-Th. intermedium translocation lines to four common wheat cultivars. A Th. intermedium chromosome 7E segment in the translocation line P98134 was preferentially transmitted through male gametes in all of its crosses with the four wheat cultivars. However, the transmission frequency of the Th. intermedium 7E segment in another wheat-Th. intermedium translocation line, P961341, varied in different genetic backgrounds. The F2 populations from reciprocal crosses of Chinese Spring and P961341 showed good fits to the expected ratio of 1: 2: 1. In this study, male preferential transmission for either chromosome 7E or chromosome 7D was observed in the progeny derived by crossing P961341 to other wheat cultivars.

Excess perennial cool-season grass production can be harvested as hay for feeding later. Thus, a series of experiments were conducted to estimate DMI and digestibility of perennial cool-season grasses relative to an annual cool-season grass hay. In Exp. 1, wheat (Triticum aestivum var. Pioneer 2174), tall wheatgrass (Thinopyrum ponticum var. Jose), smooth brome (Bromus inermis var. Lincoln), and intermediate wheatgrass (Thinopyrum intermedium var. Manska) were harvested in the spring as high-moisture hay and fed to lambs. At feeding, all 4 hays contained more (P 0.10) among the hays used in this experiment. In Exp. 2, grasses were harvested as field-dried (DM >65%) hay from established stands of Jesup Max Q (Festuca arundinacea) and Nanyro (F. arundinacea) tall fescues, Harusakae meadow fescue (Festuca pratensis), and wheat (var. Pioneer 2174). Lambs fed wheat hay had greater (P < 0.05) DMI (69.3 g/kg BW0.75, respectively) compared with lambs fed Jessup or Nanyro (35.0 and 33.8 g/BW0.75), and lambs fed Harusakae hay had intermediate DMI (50.2 g/BW0.75). Digestibility of Jesup hay was greater (P < 0.05) than digestibility of the other 3 hays. Excess cool-season grasses can be harvested as high-moisture or field-dried hay, but harvested hays had greater concentrations of ADF and NDF and a lesser concentration of N than preharvest standing forage.

Cytomixis has been described in many plant species, but not in Thinopyrum. The present study reports spontaneous cytomixis during microsporogenesis in Thinopyrum intermedium (2n = 42), Thinopyrum ponticum (2n = 70), and their F1 hybrids with wheat. Cytomixis frequently occurred in early prophase I but very rarely in meiosis II. The type of cytomixis that occurred most often was where chromatins migrate from one nucleus into an adjacent cel1. Migration from one nucleus into two or more cells or from two or more nuclei into one cel1 was also observed. After a donor cell transferred chromatin to a recipient cell, the recipient cell would sometimes pass the chromatin on to another cell. Migration did not necessarily occur between cells in the same stage. Cytomixis in Th. ponticum and its hybrids with wheat was more complex than that in Th. intermedium. The possible causes, cytological consequences and genetic significance of cytomixis are discussed.

Thinopyrum ponticum and Th. intermedium provide superior resistance against various diseases in wheat (Ttricum aestivum). Because of their readily crossing with wheat, many genes for disease resistance have been introduced from the wheatgrasses into wheat. Genes for resistance to leaf rust, stem rust, powdery mildew, Barley yellow dwarf virus, Wheat streak mosaic virus, and its vector, the wheat curl mite, have been transferred into wheat by producing chromosome translocations. These genes offer an opportunity to improve resistance of wheat to the diseases; some of them have been extensively used in protecting wheat from damage of the diseases. Moreover, new resistance to diseases is continuously detected in the progenies of wheat-Thinopyrum derivatives. The present article summaries characterization and application of the genes for fungal and viral disease-resistance derived from Th. ponticum and Th. intermedium.

Knowledge of the chromosomal distribution of long terminal repeats (LTR) is important for understanding plant chromosome structure, genomic organization and evolution, as well as providing chromosomal landmarks that are useful for chromosome engineering. The aim of this study is to investigate the genomic distribution of Sabrina -like LTR pDbH12, which was first isolated from Dasypyrum breviaristatum (V b genome), on Triticeae species in relation to the genomic evolution and chromosome identification. Fluorescence in situ hybridization (FISH) analysis showed that pDbH12 is present on Dasypyrum (V genome) and Hordeum (H genome) species with the hybridized signals covering the entire chromosomes. However, clone pDbH12 did not hybridize to the genomes of Secale, Triticum, Lophopyrum, Pseduoroengeria, Aegilops, Agropyron desertorum and Elymus. Thinopyrum intermedium displayed fourteen chromosomes that hybridized with pDbH12. Sequential FISH identified these chromosomes as belonging to the J s genome. Results ...

To date, only one gene conferring resistance to Wheat streak mosaic virus (WSMV) designated as Wsm1 was transferred from Thinopyrum intermedium (Host) Barkworth and Dewey to wheat (Triticum aestivum L.) in the form of a compensating Robertsonian translocation T4DL·4J s S. Wsm1 confers high levels of resistance to WSMV under fi eld conditions; however, in certain genetic backgrounds and environments, the presence of the T4DL·4J s S translocation reduces agronomic performance. The objective of this study was to shorten the Th. intermedium segment in the T4DL·4J s S translocation. We recovered one proximal (rec36) and four distal (rec45, rec64, rec87, rec213) primary recombinants. Genomic in situ hybridization and molecular marker analyses determined the size of the Th. intermedium segments in the distal recombinants to be about 20% of the 4DS-4J s S arm. All primary recombinant stocks, together with appropriate controls, were evaluated for their resistance to WSMV and Triticum mosaic virus (TriMV) in greenhouse tests. Whereas the distal recombinants rec45, rec64, rec87, and rec213 were resistant to both WSMV and TriMV at low temperatures of 18°C, the proximal recombinant rec36 reacted susceptible, which mapped the Wsm1 gene to the distal 20% of the 4DS-4J s S arm. We successfully shortened the Th. intermedium segment while still retaining the Wsm1 gene. The T4DL·4DS4J s S recombinant chromosome of the rec213 stock was transferred to adapted Kansas hard red winter wheat cultivars.

The wheatgrass, Thinopyrum intermedium (Host) Barkworth & DR Dewey, shows many beneficial characteristics, such as big spikes and high resistance to many diseases. To transfer the beneficial genes of this species, many wheat-Thinopyrum intermedium alien chromosome lines were developed. Of them, Shannong 0095 (SN0095), a disomic substitution, has long spikes and flag-leaves, and thus may be an important genetic resource for wheat yield improvement. In order to realize its heterosis and combining ability on major yield traits, a 7 × 7 complete diallel design was made according to Griffing's Method-I. The results showed that heterosis for spike length (SPL), flag-leaf area (FLA), number of spikes per plant (NSP), number of spikelets per spike (NSL), kernels per spike (KPS), 1 000-kernel weight (TKW) and grain yield per plant (GYP) existed in all the crosses by SN0095, but heterobeltiosis occurred only for KPS, TKW, and GYP. The relative mid-parent heterosis (RMH) and relative high-parent heterosis (RHH) for GYP, which valued as high as 35.32 and 29.92% respectively, were the highest among all the traits mearsured. Though additive and non-additive gene effects and cytoplasmic effects (or cytoplasmic-nuclear interaction effects) were found in governing all the traits measured above, additive gene action played a predominant role. The results also showed that SN0095 was the best-general combiner for SPL and FLA, and high-general combiner for NSP amongst all the parents. Estimates of specific combining ability (SCA) showed that SN0095 could also make high-SCA combinations for GYP, such as SN0095 × Jimai 19 (JM19). SN0095 could be a unique and important parent in hybrid wheat breeding programs.

Barley yellow dwarf virus (BYDV) can cause significant losses of wheat worldwide. The long arm segment of Thinopyrum intermedium chromosome 7Ai#1 carrying the BYDV resistance gene Bdv2 was translocated to the distal region of the long arm of wheat chromosome 7D in translocation line Yw642. In this study, 40 wheat EST sequences located in the distal region of 7DL were explored to identify specific PCR markers for the Bdv2 region on the basis of the homoeologous relationship between wheat chromosome 7D and Th.intermedium chromosome 7Ai#1. Our results revealed 8 novel EST-PCR markers specific to the Bdv2 region, including 5 EST-STS markers of BE404744, BE498985, BE591497, BG606695 and BQ161842, and 3 EST-SSCP markers of BE404953, BG312663 and BE498985. These EST-PCR markers could distinguish Bdv2 from another BYDV-resistance gene located on Th.intermedium chromosome 2Ai-2. These specific bands for the Bdv2 region were further cloned and sequenced. The sequencing analysis indicated that the specific sequences for the Bdv2 region were highly homologous with the original wheat EST sequences that were used to design primers, and encode respectively a protein kinase, P450, centrin, transducin, and a hypothetical protein. This study created a starting point for eventual cloning of the Bdv2 gene and understanding the defense mechanism.

Wild tall wheatgrass (Lophopyrum elongatum L., 2x = 14) is an important resource for improving bread wheat (Titicum aestivum L.), including HMW-GS and LMW-GS relevant to end-use quality of the wheat flour. A set of 14 distinct sequences were amplified from the genomic DNA of the tall wheatgrass, using degenerate primers targeted at Glu-3, the locus containing the genes encoding the low-molecular weight glutenin subunits (LMW-GS). Three sequences contained an internal stop codon and were classified as pseudogenes. The other 11 all consisted of a single intron-less intact open-reading frame. An alignment of deduced protein sequences showed that the primary structure of all 11 sequences was similar to that of wheat and other wheat-related grass Glu-3 genes. All 11 sequences carried the 14 amino acid residue N-terminal motif MESNIIISFLK/RPWL, and were classified as LMW-m genes, based on the identity of the first amino acid of the mature protein. All but one of the sequences contained seven cysteine residues (the exception had 6). Their repetitive domain differs significantly from that present in Glu-3 genes isolated from the close relative intermediate wheatgrass (Thinopyrum Intermedium, 6x). A phylogenetic analysis showed that the tall wheatgrass sequences were closely related to those of the intermediate wheatgrass, but only distantly so to those from decaploid tall wheatgrass. One of the 11 LMW-GS peptides with a free-cysteine residue was heterologously expressed in E. coli and purified in sufficient scale to perform a flour supplementation test. This showed that the dough strength of bread wheat flour was significantly increased by the presence of the tall wheatgrass LMW-GS.

Thinopyrum intermedium carries many useful traits for wheat genetic improvement. To identify genes conferring resistance to stripe rust caused by Puccinia striiformis f. sp. tritici in Zhong4, one of the Zhong series of partial amphiploids from the hybrids of common wheat × Th. intermedium, a cross was made between Zhong4 and a Chinese Spring ph1b mutant (CS-ph1b). The parents, F1, F2 plants and F5 lines of the cross were tested with Chinese predominant race CYR31 of P. striiformis f. sp. tritici in the seedling stage under controlled greenhouse conditions. Of 201 F2 seedlings tested with race CYR31, 149 were resistant and 52 were susceptible. The segregation fit a 3 resistant:1 susceptible ratio, indicating that a single dominant gene conferred resistance to the race CYR31. This result was further confirmed by the segregation of F5 lines into 1:1 ratio (P = 0.77). Using the Schiff dyeing method, the chromosome number in the root-tip cells of 10 F5 resistant lines (total 42 plants) was determined. Two alien addition lines (5-1-2-1-1-5, 5-1-2-1-1-6) with the smallest chromosome number (2n = 42 + II) were identified. A total of 105 pollen mother cells were examined at metaphase 1 (PMCs MI) for meiotic chromosome pairing. The lines 5-1-2-1-1-5 and 5-1-2-1-1-6 showed regular meiosis, exhibiting 22 ring or rod bivalents (2n = 22 II). The GISH results indicated that lines 5-1-2-1-1-5 and 5-1-2-1-1-6 were wheat-Th. intermedium alien disomic addition lines with 21 pairs of wheat chromosomes and one pair of Th. intermedium chromosomes. These two lines were all resistant to stripe rust, suggesting that they can be used as donors of stripe rust resistance genes and have great potential to play important roles in wheat stripe rust resistance breeding programs in China and the world.Key words: Wheat-Thinopyrum intermedium, stripe rust, GISH, cytological identification

The aim of this study was to provide cytogenetical evidence on the behavior of chromosome 2Ai-2 from Thinopyrum intermedium in different wheat ( Triticum aestivum L.) chromosome substitution backgrounds. Five wheat-alien disomic or ditelosomic substitution lines were crossed with the common wheat variety Chinese Spring to produce the BC 1 and F 2 populations, which were tested with expressed sequence target (EST)-PCR markers specific to chromosome 2Ai-2 and genomic in situ hybridization (GISH) analysis. In the 2Ai-2(2B) substitution background, the alien chromosome or its fragment was transferred to offspring with higher ratio than the expected ratio, whereas the transmission ratios were much lower than the expectation in the 2Ai-2(2D) background. The 2Ai-2 chromosome was transferred preferentially through heterozygosis in the 2Ai-2(2B) background. Structural changes of 2Ai-2 occurred frequently in progenies, most of which were near the centromere. Compared with the short arm, the long arm of the alien chromosome was lost more frequently in the next generations. The F 2 plants with 2AS-substitution background were rare when detected with 2Ai-2S-specific EST-PCR marker(s), suggesting that the alien telosome might be lost frequently. Structural variation of the telosomic chromosome 2Ai-2S was also observed in the offspring with 2AS-substitution background. The GISH results confirmed that the EST-PCR markers can be applied in tracing the alien chromosome in wheat background.

‘Mace’ (Reg. No. CV-1027, PI 651043) hard red winter wheat (Triticum aestivum L.) was developed by the USDA-ARS and the Nebraska Agricultural Experiment Station and released in December 2007. Mace was selected from the cross Yuma//PI 372129/3/CO850034/4/4*Yuma/5/(KS91H184/Arlin S//KS91HW29/3/NE89526). Mace primarily was released for its resistance to Wheat streak mosaic virus (WSMV) and adaptation to rainfed and irrigated wheat production systems in Nebraska and adjacent areas in the northern Great Plains. Mace was derived from a head selection made from a heterogeneous, in terms of fi eld resistance to WSMV, F 5 line. Resistance to WSMV is conditioned by the Wsm-1 gene, located on an introgressed chromosome arm from Thinopyrum intermedium (Host) Barkworth & D.R. Dewey [Agropyron intermedium (Horst.) Beauv.] present as a 4DL.4AgS chromosomal translocation. Mace was tested under the experimental designation N02Y5117.

The common wheat line, YW243, developed in our research group, was tested for the resistances of barley yellow dwarf virus (BYDV), powdery mildew (Pm) and stripe rust in field, and was analyzed by molecular markers for convenient trace of the resistant genes in breeding. Genomic in situ hybridization (GISH) analysis and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) assay further demonstrated that YW243 was a homozygous multiple translocation line of Triticum aestivum, Thinopyrum intermedium and Secale cereale (T7DS·7DL-7XL & 1BL·1RS). The disease resistance test and marker analysis showed that YW243 carried seven resistance genes to the three diseases, including Bdv2 to BYDV on 7DL-7XL, Pm4 to powdery mildew on 2AL, Yr2, Yr9, Sr 31 and Lr26 and a new Yr to stripe rust on 7B, 1BL, 1RS and 2BL. Restriction fragment length polymorphism (RFLP) markers Xpsr687 and Xwg380, sequence tagged site (STS) marker STS1700, simple sequence repeat (SSR) markers Xgwmc364 and Xgwm582, SSR markers Xgwm388 and Xgwm501 can be used as diagnostic tools to track Bdv2, Pm4, Yr2, Yr9 and Yr in YW243, respectively; and two amplified fragment length polymorphism (AFLP) markers M54E63-700 and M54E64-699 can also be used to select Yr in YW243.

Intermediate wheatgrass [Thinopyrum intermedium (Host) Barkw. & D.R. Dewey subsp. intermedium] is a productive, high-quality perennial forage that lacks persistence under grazing. A study was conducted to evaluate the effects of three grazing times on soil bulk density, soil pH, and soil organic C under intermediate wheatgrass. Treatment effects on the three soil attributes were negligible, implying grazing time did not negatively impact intermediate wheatgrass beyond a threshold whereby critical soil functions were impaired. Findings from this study are important in the context of sustainable forage and cropping system management, where maintaining or improving critical soil functions are essential for enhancing agroecosystem sustainability. Key words: Seeded perennial forages, Northern Great Plains, soil organic C

Wheat sharp eyespot, primarily caused by a soil-borne fungus Rhizoctonia cerealis, has become one of the most serious diseases of wheat in China. In this study, an ethylene response factor (ERF) gene from a wheat relative Thinopyrum intermedium, TiERF1, was characterized further, transgenic wheat lines expressing TiERF1 were developed, and the resistance of the transgenic wheat lines against R. cerealis was investigated. Southern blotting analysis indicated that at least two copies of the TiERF1 gene exist in the T. intermedium genome. Yeast one-hybrid assay indicated that the activation domain of TiERF1 is essential for activating the transcript of the reporter gene with the GCC-box cis-element. The TiERF1 gene was introduced into a Chinese wheat cultivar, Yangmai12, by biolistic bombardment. Results of PCR and Southern blotting analyses indicated that TiERF1 was successfully integrated into the genome of the transgenic wheat, where it can be passed down from the T0 to T4 generations. Quantitative reverse transcription-PCR analysis demonstrated that TiERF1 could be overexpressed in the stable transgenic plants, in which the expression levels of wheat pathogenesis-related (PR) genes primarily in the ethylene-dependent signal pathway, such as a chitinase gene and a beta-1,3-glucanase gene, were increased dramatically. Disease tests indicated that the overexpression of TiERF1 conferred enhanced resistance to sharp eyespot in the transgenic wheat lines compared with the wild-type and silenced TiERF1 plants. These results suggested that the overexpression of TiERF1 enhances resistance to sharp eyespot in transgenic wheat lines by activating PR genes primarily in the ethylene-dependent pathway.

Thinopyrum intermedium is resistant to many different pathogens. To understand the roles of ethylene response factors (ERFs) in defence responses, the first member of the ERF family in T. intermedium, TiERF1, was characterized and functionally analysed in this study. The TiERF1 gene encodes a putative protein of 292 amino acids, belonging to the B3 subgroup of the ERF transcription factor family. Biochemical assays demonstrated that the TiERF1 protein is capable of binding to the GCC box, a cis-element present in the promoters of pathogenesis-related (PR) genes, and possessing transactivation activity, as well as localizing to the nucleus. The transcript of TiERF1 in T. intermedium is rapidly induced by infection with Rhizoctonia cerealis, Fusarium graminearum, or Blumeria graminis, and ethylene, jasmonic acid, and salicylic acid treatments. More importantly, the ectopic expression of TiERF1 in tobacco activated the transcript of the PR genes of tobacco with a GCC box cis-element, and ACO and ACS genes key to ethylene synthesis, and in turn improved the resistance level to Alternaria alternata and tobacco mosaic virus, as well as causing some phenotypic changes associated with ethylene response in the transgenic tobacco plants. Taken together, TiERF1 protein as an ERF transcription activator positively regulates defence responses via the activation of some defence-related genes.

为了探索中间偃麦草SGT1基因在小麦抗病反应中的应用潜力，采用RT-PCR和RACE方法克隆出中间偃麦草SGT1基因，命名为TiSGT1。该基因编码蛋白具有SGT1蛋白典型的功能域结构，与大麦SGT1序列高度同源。通过基因重组技术构建了TiSGT1的高效组成型表达载体，通过基因枪法将该载体转化到小麦品种扬麦12基因组中。对转基因植株PCR、Southern杂交与RT-PCR分析表明，TiSGT1基因可在T0、T1和T2代转基因小麦中遗传和表达。黄矮病、白粉病抗性鉴定结果表明，SGT1的超量表达可以提高小麦对黄矮病、白粉病的抗性，TiSGT1可以作为小麦广谱抗病性改良的潜在基因资源。