and Central Siberian Botanical Garden, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia (A.A.K.) Bread wheat (Triticum aestivum) inflorescences, or spikes, are characteristically unbranched and normally bear one spikelet per rachis node. Wheat mutants on which supernumerary spikelets (SSs) develop are particularly useful resources for work towards understanding the genetic mechanisms underlying wheat inflorescence architecture and, ultimately, yield components. Here, we report the characterization of genetically unrelated mutants leading to the identification of the wheat FRIZZY PANICLE (FZP) gene, encoding a member of the APETALA2/Ethylene Response Factor transcription factor family, which drives the SS trait in bread wheat. Structural and functional characterization of the three wheat FZP homoeologous genes (WFZP) revealed that coding mutations of WFZP-D cause the SS phenotype, with the most severe effect when WFZP-D lesions are combined with a frameshift mutation in WFZP-A. We provide WFZPbased resources that may be useful for genetic manipulations with the aim of improving bread wheat yield by increasing grain number.

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Acrylamide, a monomer with neurotoxic and potential carcinogenic effect, is formed via the Maillard reaction in heat-treated carbohydrate-rich foods. The major acrylamide precursors are reducing sugars and the amino acid asparagine. The aim of this study was to analyse effects of nitrogen nutrition, leaf disease control, wheat genotype and their interactions on acrylamide precursors content in wheat flour. Asparagine content was generally increasing at higher nitrogen doses, and nitrogen dose increase from 0 to 180 kg/ha increased the asparagine content to about 250%. The highest asparagine levels were determined at early spring nitrogen application. In the year 2006 with high leaf disease infestation, fungicide treatment decreased asparagine content particularly at higher nitrogen doses. In 2007, the effect of leaf disease control did not express in respect of very low infestation level. Close relationship between protein content and free asparagine in wheat flour was determined when leaf disease stress (fungicide treatment) and drought stress (year) were constant. Asparagine content was strongly influenced by wheat genotype and the differences between genotypes exceeded 200%. Effect of higher intensity was lower as compared to nitrogen nutrition, with regard to compensatory effect of fungicide treatments. Glucose content in wheat flour decreased both with fungicide treatment and total intensity level. Nitrogen dose increased glucose content up to 120 kg N/ha. Higher nitrogen doses decreased glucose content to initial level.

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The wheat and rye spike normally bears one spikelet per rachis node, and the appearance of supernumerary spikelets is rare. The loci responsible for the 'multirow spike' or MRS trait in wheat, and the 'monstrosum spike' trait in rye were mapped by genotyping F(2) populations with microsatellite markers. Both MRS and the 'monstrosum' trait are under the control of a recessive allele at a single locus. The Mrs1 locus is located on chromosome 2DS, co-segregating with the microsatellite locus Xwmc453. The placement of flanking microsatellite loci into chromosome deletion bin 2DS-5 (FL 0.47-1.0) delimited the physical location of Mrs1 to the distal half of chromosome arm 2DS, within the gene rich region 2S0.8. The Mo1 locus maps about 10 cM from the centromere on chromosome arm 2RS. The similar effect on phenotype of mo1 and mrs1, together with their presence in regions of conserved synteny, suggest that they may well be members of an orthologous set of Triticeae genes governing spike branching. The practical importance of the MRS spike is that it produces more spikelets per spike, and thereby enhances the sink capacity of wheat, which is believed to limit the yield potential of the crop.