ITEMS FROM THE UNITED KINGDOM

JOHN INNES CENTRE

Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom.

Tritypyrum: further studies of this salt-tolerant potential cereal.

H.S. Hasani, P.D.S. Caligari (The University of Reading), S.M. Reader, and T.E. Miller.

A small field trial of tritipyrum showed that multiple tillering was less pronounced under field conditions and that tritipyrum has better winter hardiness than its wheat parents. Late maturity is not due to a vernalization requirement. Overcoming the undesirable characters by replacing Thinopyrum chromosomes with D-genome chromosomes from bread wheat is feasible, and this approach could be used to introduce beneficial characters such as reduced height and bread-making quality.

One tritipyrum line exhibits a novel multiple pistil­multiple seed trait, which appears to be the result of two recessive genes, one in wheat and one in Th. bessarabicum. The individual Th. bessarabicum chromosomes were isolated in the form of monosomic addition lines for locating these genes on chromosomes.

Tritypyrum may never compete with the major cereals, but it has potential for saline areas that currently will not support a crop. Because of its perennial multitillering habit, it might be utilized as a dual-purpose forage/grain crop to support animal production rather than a source of direct human nutrition.

Characterization of Aegilops uniaristata chromosomes using molecular markers and in situ hybridization.

N. Iqbal, S.M. Reader, P.D.S. Caligari (The University of Reading) and T.E. Miller.

The homoeologous relationships of six addition-line chromosomes of Ae. uniaristata in Chinese Spring wheat were identified by RFLP analysis. Chromosome 6N was not detected in the available lines. The highly heterobrachial chromosome 3N, which carries the genes for aluminium tolerance, red grain, and brittle rachis, was shown to have arisen by an asymmetric pericentric inversion. A large segment of the short arm (from the centromere to probe PSR1196) was transferred to the long arm and a small piece of the long arm (from the centromere to probe PSR56) to the short arm. RFLP analysis confirmed the T3BL·3NL Robertsonian translocation.

The individual Ae. uniaristata chromosomes were characterized by FISH for the presence and location of the repetitive DNA sequences pSC119.2, pAS1 and pTA71. This has resulted in an update of the ideogram of Badaeva et al. (Genome 39:1150-1158, 1996). The chromosomes were assigned homoeologies based on the karyotype of the species and the individual chromosomes in the addition lines. A few errors, presumably arising from misidentification of chromosomes with nearly identical morphology in preparations of Ae. uniaristata, also have been resolved.

Mutagenesis of three major genes for yellow rust resistance.

R.M.D. Koebner and J. Hadfield.

As the initial phase of a program to isolate genes encoding yellow rust resistance in wheat, we have mutagenized three independent loci: Yr1, Yr5, and Yr10 (represented as isogenic lines in the susceptible background Lemhi). The strategy was to mutagenize individuals hemizygous for chromosome with the target resistance gene. Single, critical mutation events can then be selected in the M1 generation. To generate large numbers of hemizygotes, the isogenic Yr lines each were crossed with the relevant Chinese Spring monosomic. Monosomic, F1 segregants selected on the basis of SSR phenotype were self-fertilized. In this way, we exploited the high frequency of transmission of monosomy among self-fertilized progeny of a monosomic plant. The material to be mutagenized was a mixture of hemizygous, disomic, and nullisomic individuals, with the former predominating. Disomic progeny were expected to be largely homozygous resistant (heterozygous resistant if mutated) and were not selected. Any viable nullisomics, which were susceptible, were identified by SSR analysis. This procedure avoided the need to screen the M2 and also permitted controlled inoculation with a specific pathogen isolate, which would not have been possible under field conditions.

The three resulting populations (Yr1-14,300 seeds, Yr5-4,500 seeds, and Yr10-8,300 seeds) were irradiated with fast neutrons at the IAEA reactor in Seibersdorf. Flats that each held approximately 300 seedlings were inoculated with yellow rust under controlled conditions and placed in a containment glasshouse. The Yr1 population generated 603 susceptible seedlings (4.2 %). Of these, 17 were self sterile, five were nullisomics (all fertile), and 24 were chimeric (giving segregating progeny), leaving a total of 581 lines with the Yr1 chromosome, but without a functional Yr1 locus. For Yr5, the proportion of susceptible individuals was much lower (71 plants, 1.6 %), and the number of unfertile putative mutants much higher (57 %), including a large proportion of grass-clump plants. Eighteen of the remaining 30 selections were chimeric. For Yr10, 240 susceptible individuals (2.9 %) have been identified, but progeny tests have not yet been made.

Fine-scale mapping with AFLP and RGA markers is underway on these selections to order the mutants and will provide a suitable resource for the isolation of the genes by chromosome walking/landing.

The gibberelic acid-insensitive dwarfing gene Rht21.

A.J. Worland and E. Sayers.

A new GA-insensitive dwarfing gene, Rht21, has been identified on chromosome 2A of XN0004 by Yang et al. 1995. The location of a GA-insensitive dwarfing gene on a group-2 chromosome is interesting, because all previous gene locations in wheat have been on chromosomes 4B or 4D. The group-2 chromosomes have been implicated in GA synthesis. Test crosses of XN0004 with a group-2 monosomic and tester lines with Rht1 or Rht2 were made at the John Innes Centre. Initial results show that among 300 F2 progeny of XN0004 and the Rht2 test line, all progeny were GA insensitive, suggesting that Rht21 is allelic to Rht2. Backcrossing of Rht21 into five different varietal backgrounds is continuing to confirm whether Rht21 is identical to Rht2 or represents a novel allele at the chromosome 4D locus for GA-insensitive dwarfing genes.

Reference.

TZ Yang, XK Zhang, HW Liu and ZH Wang. 1995. Chromosomal arm location of a dominant dwarfing gene Rht21 in XN 0004 of Common wheat. In: Proc 8th Inter Wheat Genet Symp (Li ZS and Xin ZY eds). China Agric Scientech Press, Beijing, China. pp 839-843.

Distribution of Rht8 in international wheat cultivars.

A.J. Worland and V. Korzun (I.P.K. Gatersleben, Germany)

The detection of an 192-bp allelic variant of the WMS261 wheat microsatellite locus as a molecular tag for the dwarfing gene Rht8 has been fully described. Work has continued using WMS 261 to screen diverse cultivars for the presence of Rht8.

Rht8 probably originated in Japanese cultivars and was introduced into international cultivars by the Italian breeder Strampelli. His key cross 'Akakomugi // Wilhelmina / Rieti' combined cultivars with three different alleles at the WMS 261 locus (192, 174, and 165 bp, respectively). The 192-bp allele diagnostic of Rht8 has been transmitted to virtually all tested southern European cultivars including 48 of 50 screened Yugoslavian winter wheat cultivars. Rht8 is important to the adaptability of southern European wheats, all of which lack the more universal gibberelic acid-insensitive dwarfing genes Rht1 or Rht2 from Norin 10.

Until recently, varietal screening failed to detect cultivars with Rht8 outside the southern European and Russian breeding programs. A recent screening of Chinese wheats has detected the 192-bp allele of WMS 261 diagnostic of Rht8 in 30 of 52 screened cultivars from China. Interestingly, 22 of the cultivars that carry Rht8 also carry a GA-insensitive dwarfing gene, presumably Rht1 or Rht2. In CIMMYT breeding programs where Rht1 or Rht2 is universal to their semidwarf cultivars, Rht8 is never detected but is replaced by a height-promoting allele of 165 bp at the WMS 261 locus. This allele is thought to counteract the strong dwarfing effects of Rht1 or Rht2 and prevent the CIMMYT wheats from being too short. The same counterbalancing obviously is not present in Chinese wheats.

Physical characterization of the homoeologous group-5 chromosomes of wheat in terms of rice linkage blocks and physical mapping of genes for flowering time.

R.N. Sarma, L.J. Fish, B.S. Gill (Department of Plant Pathology, Kansas State University, Manhattan, KS, USA), and J.W. Snape.

The homoeologous group-5 chromosomes of wheat have been characterized physically in terms of rice linkage blocks using a deletion mapping approach. Chromosomes 5A, 5B, and 5D were revealed to have a similar structure, apart from the 4A/5A translocation on the distal end of chromosome arm 5AL. Physical mapping of rice markers on the deletion lines revealed that the entire rice chromosome 9 constitutes a large block proximal to the centromere on the long arm. Likewise, a small segment of the distal end of the long arm showed homoeology with the distal one third of the long arm of rice chromosome 3. In between those conserved regions is a region on the long arm of the group-5 chromosomes that shows broken synteny. The proximal part of the short arms of the group-5 chromosomes showed homoeology with a segment of the short arm of rice chromosome 11, and the distal ends showed homoeology with a segment of rice chromosome 12.

The physical location of the Vrn1 genes, midway along the long arms, was defined as being in segments orthologous to chromosome 3 of rice. New earliness genes per se were defined in regions proximal to the centromere on the long arm in a region orthologous to rice chromosome 9. These results indicate that comparative mapping using the deletion mapping approach is useful to study conserved synteny across species and the physical location of genes and to determine gene-cloning strategies in wheat. in 30 of 52 screened cultivars from China. Interestingly, 22 of the cultivars that carry Rht8 also carry a GA-insensitive dwarfing gene, presumably Rht1 or Rht2. In CIMMYT breeding programs where Rht1 or Rht2 is universal to their semidwarf cultivars, Rht8 is never detected but is replaced by a height-promoting allele of 165 bp at the WMS 261 locus. This allele is thought to counteract the strong dwarfing effects of Rht1 or Rht2 and prevent the CIMMYT wheats from being too short. The same counterbalancing obviously is not present in Chinese wheats.

Publications.

Aragón-Alcaide L, Beven A, Moore G, and Shaw P. 1998. The use of vibratome sections of cereal spikelets to study anther development and meiosis. Plant J 14:503-508.

Blatter RHE, Brown J KM, and Wolfe M S. 1998. Genetic control of the resistance of Erysiphe graminis f.sp. hordei to five triazole fungicides. Plant Path 47:570-579.

Borner A, Korzun V, and Worland AJ. 1998. Comparative genetic mapping of loci affecting plant height and development in cereals. Euphytica 100:245-248.

Brammer SP, Worland AJ, Barcellos AL, and De Fernandes MIB. 1998. Monosomic anlaysis of adult-plant resistance to leaf rust in the Brazilian wheat cultivar 'Toropi'. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 2:17-18.

Brown JKM. 1998. How to feed the world, in two contradictory lessons. Trends Plant Sci 3:409-410.

Brown JKM. 1998. Surveys of variation in pathogen population and their application to disease control. In: The Epidemiology of Plant Diseases (Jones DG ed). Dordrecht, Kluwer Academic Publishers. pp. 73-102.

Butterworth KJ and Worland AJ. 1998. Influence of the Ppd-D1 photoperiod gene on the adaptability of European wheats. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 2:173-176.

Donini P, Stephenson P, Bryan GJ and Koebner RMD. 1998. The potential of microsatellites for high throughput genetic diversity assessment in wheat and barley. Genet Res Crop Evol 45:415-421.

Doohan FM, Parry DW, Jenkinson P, and Nicholson P. 1998. The use of species-specific PCR-based assays to analyse Fusarium ear blight of wheat. Plant Path 47:197-205.

Flintham JE and Gale MD. 1998. Plant height and yield components of inbred isogenic and F1 hybrid Rht dwarf wheats. J Appl Genet 39:73-83.

Gale MD and Devos KM. 1998. Comparative genetics in the grasses. Proc Natl Acad Sci USA 95:1971-1974.

Gale MD and Devos KM. 1998. Plant comparative genetics after ten years. Science 282:656-659.

Galiba G, Kerpesi I, Snape JW and Sutka J. 1998. Mapping of genes controlling cold hardiness on wheat 5A and its homoeologous chromosomes of cereals. In: Plant Cold Hardiness: Molecular Biology, Biochemistry and Physiology (Li P and Chen THH eds). Plenum Publishing Corporation, New York. pp. 89-98.

Hague RE. 1998. Genetics of quantitative resistance to powdery mildew in Fenman winter wheat. Ph.D. Dissertation, University of East Anglia.

Hassani HS. 1998. Development and molecular cytogenetic studies of a new potential salt tolerant cereal tritipyrum. Ph.D. Dissertation, The University of Reading.

Hassani HS, King IP, Reader SM, Caligari PDS, and Miller TE. 1998. An assessment of Tritipyrum, a new potential cereal with salt tolerance. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 4:31-33.

Iqbal N. 1998. Characterization of Ae uniaristata chromosome and the transfer of aluminium tolerance to wheat by induced recombination. Ph.D. Dissertation, The University of Reading.

Iqbal N, Reader SM, Caligari PDS, and Miller TE. 1998. Characterization of Aegilops uniaristata chromosomes using molecular markers.. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press,Saskatoon, Saskatchewan, Canada. 3:114-116.

Koebner RMD and Bothe R. 1998. Anwendung molekularer Marker zur Optimierung von Weizen-Roggen- Translokationslinien. Biotechnologie in der PflanzenzüchtungPotentiale und aktuelle Nutzung. Vorträge für Pflanzenzüchtung 43:9-14.

Koebner RMD, Kirsch F, Thorpe C, and Prins R . 1998. AFLPs as a source of STS markers in alien introgression. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 1:118-122.

Koebner RMD, Kirsch F, Thorpe C and Van Campenhout S. 1998. Generation of STS markers for wheat/rye introgression. Biotechnologie in der Pflanzenzüchtung - Potentiale und aktuelle Nutzung. Vorträge für Pflanzenzüchtung 43:15-22.

Korzun V, Röder MS, Ganal MW, Worland AJ, and Law CN. 1998. Genetic analysis of the dwarfing gene (Rht8) in wheat. Part 1. Molecular mapping of Rht8 on the short arm of chromosome 2D of bread wheat (Triticum aestivum L.). Theor Appl Genet 96:1104-1109.

Lapinski B and Schwarzacher T. 1998. Chromatid bridges in mitosis of tetraploid triticale. In: Plant Cytogenetics (Maluszinska Y ed). Prace Naukowe Uniwerstetu, Katowice, Poland. pp. 184-189.

Lapinski B and Schwarzacher T. 1998. Wheat-rye translocations in the imporoved lines of 4x-triticale. In: Plant Cytogenetics (Maluszinska Y ed). Prace Naukowe Uniwerstetu, Katowice, Poland. pp. 211-215.

Law CN, Suarez E, Miller TE, and Worland AJ. 1998. The influence of the group 1 chromosomes of wheat on ear-emergence times and their involvement with vernalization and day length. Heredity 80:83-91.

Law JR, Donini P, Koebner RMD, Reeves JC, and Cooke RJ. 1998. DNA profiling and plant variety registration. III: the statistical assessment of distinctness in wheat using amplified fragment length polymorphisms. Euphytica 102:335-342.

Leister D, Kurth J, Laurie DA, Yano M, Sasaki T, Devos K, Graner A, and Schulze-lefert P. 1998. Rapid reorganization of resistance gene homologues in cereal genomes. Proc Natl Acad Sci USA 95:370-375.

Li X, Pang C, Wu J, Worland AJ, Gale MD, and Brown SJ. 1998. Analysis of advantages and disadvantages of different Rht dwarfing genes in winter wheat breeding. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 2:273-276.

McIntosh RA, Hart GE, Devos KM, Rogers WJ, and Gale MD. 1998. Catalogue of gene symbols for wheat: 1998 supplement. Wheat Inf Serv 86:54-91.

McIntosh RA, Hart GE, Devos KM, Gale MD, and Rogers WJ. 1998. Catalogue of gene symbols for wheat. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 5:1-335.

Miller TE, Reader SM, Shaw PJ, and Moore G. 1998. Towards an understanding of the biological action of the Ph1 locus in wheat. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 1:17-19.

Moore G. 1998. To pair or not to pair: chromosome pairing and evolution. Curr Op Pl Biol 1:116-122.

Nicholson P, Simpson DR, Weston G, Rezanoor HN, Lees AK, Parry DW, and Joyce D. 1998. Detection and quantification of Fusarium culmorum and Fusarium graminearum in cereals using PCR assays. Physiol Mol Plant Path 53:17-37.

Qu L-J, Foote TN, Roberts MA, Money TA, Aragón-Alcaide L, Snape JW, and Moore G. 1998. A simple PCR-based method for scoring the ph1b deletion in wheat. Theor Appl Genet 96:371-375.

Reader SM, Aragón-Alcaide L, Moore G, and Miller TE. 1998. Centormeres, telomeres, fluorescent in situ hybridization. In: Current topics in plant cytogenetics related to plant improvement (Lelley T ed). NUV Universitatsverlag, Vienna. pp. 111-116.

Reader SM, Aragón-Alcaide LG, Moore G, Shaw P, Beven A, and Miller TE. 1998. What does Ph1 really do in wheat? EWAC Newsl, Proc10th EWAC Meeting, Viterbo, Italy. pp. 55-57.

Sarma RN. 1998. Comparative mapping of flowering time genes in rice, wheat and barley. Ph.D. Dissertation, University of East Anglia.

Sarma RN, Gill BS, Sasaki T, Galiba G, Sutka J, Laurie DA, and Snape JW. 1998. Comparative mapping of the wheat chromosome 5A Vrn-A1 region with rice and its relationship to QTL for flowering time. Theor Appl Genet 97:103-109.

Shaw P and Moore G. 1998. Meiosis: vive la difference! Curr Op Pl Biol 1:458-462.

Snape JW. 1998. Golden calves or white elephants? Biotechnologies for wheat improvement. Euphytica 100:207-217.

Snape JW and Laurie DA. 1998. Comparative mapping of agronomic trait loci in crop species. In: Crop Productivity and Sustainability - Shaping the Future: Proc 2nd Inter Crop Sci Cong (Chopra VL, Singh RB, and Varma A eds). IBH Publishing Co. PVT Ltd, New Dehli, India. pp. 759-771.

Snape JW, Sarma RN, Zhang W, Semikhodskii A, Fish L, Galiba G, Sutka J, Gill BS, Sasaki T, and Laurie DA. 1998. Genetic mapping of key genes on chromosomes of homoelogous group 5 of wheat. EWAC Newsl, Proc10th EWAC Meeting, Viterbo, Italy. pp. 53-55.

Snape JW, Semikhodskii A, Sarma R, Korzun V, Fish L, Quarrie SA, Gill B S, Sasaki T, Galiba G and Sutka J. 1998. Mapping vernalization loci in wheat and comparative mapping with other cereals. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 3:156-158.

Stephenson P, Bryan G, Kirby J, Collins A, Devos K, Busso C, and Gale M. 1998. Fifty new microsatellite loci for the wheat genetic map. Theor Appl Genet 97:946-949.

Sutka J, Galiba G, Vagujfalvi A, Koszegi B, Snape JW. 1998. Genes for frost resistance and drought tolerance on chromosome 5A of wheat (Triticum aestivum L.). EWAC Newsl: Proc10th EWAC Meeting, Viterbo 88-91.

Sutka J, Galiba G, Vieisz O and Snape JW. 1998. Genes and breeding for cold hardiness in cereals. In: Crop Development for Cool and Wet Regions of Europe (Sowinski P, Zagdanska B, Aniol A, and Pitham K eds). CIOST 814-II European Commission. pp. 243-256.

Turner AS, Lees AK, Rezanoor HN, and Nicholson P. 1998. Refinement of PCR-detection of Fusarium avenaceum and evidence from DNA marker studies for phenetic relatedness to Fusarium tricinctum. Plant Path 47:278-288.

Uslu E, Miller TE, Rezanoor NH, and Nicholson P. 1998. Resistance of Dasypyrum villosum to the cereal eyespot pathogens, Tapesia yallundae and Tapesia acuformis. Euphytica 103:203-209.

Worland AJ, Börner A, Korzun V, Li WM, Petrovic S, and Sayers EJ. 1998. The influence of photoperiod genes on the adaptability of European winter wheats. Euphytica 100:385-394.

Worland AJ, Korzun V and Petrovic S. 1998. The presence of the dwarfing gene Rht8 in wheat varieties of the former Yugoslavian Republics as detected by a diagnostic molecular marker. In: Proc 2nd Balkan Symp Field Crops, Novi Sad, Yugolsavia. pp. 16-20.

Worland AJ, Korzun V, Röder MS, Ganal MW, and Law CN. 1998. Genetic analysis of the dwarfing gene Rht8 in wheat. Part II. The distribution and adaptive significance of allelic variants at the Rht8 locus of wheat as revealed by microsatellite screening. Theor Appl Genet 96:1110-1120.

Yalvac K. 1998. Molecular markers as selection tools for introgression of alien disease resistance into wheat. Ph.D. Dissertation, University of East Anglia.

Zhang H, Jia J, Gale MD, and Devos KM. 1998. Relationships between the chromosomes of Aegilops umbellulata and wheat. Theor Appl Genet 96:69-75.

Zhou R, Jia J, Dong Y, Schwarzacher T, Reader SM, Wu S, Gale MD, and Miller TE. 1998. Characterization of Triticum aestivum/Psathyrostachys juncea derivatives by genomic in situ hybridization. Euphytica 99:85-88.