Abstract:The reaction of winter and spring wheat to infection with barley yellow dwarf virus (BYDV-PAV) was evaluated in three-year small-plot field trials on 71 wheat varieties registered in the Czech Republic and at two locations for two years on 63 selected potential sources of resistance. Disease symptoms (VSS) were visually recorded using a 0-9 scale and the percent reduction of grain weight per spike (GWS-R) was measured on twenty plants per plot. The evaluation showed that among the registered varieties of winter and spring wheat no variety had a high resistance to BYDV (with VSS lower than 3.5). GWS-R ranged between 24% and 60%. Higher variability in VSS was detected for the registered varieties of spring wheat compared to winter wheat. Among the registered varieties of winter wheat, Saskia, Rialto, Meritto, Rexia, and Svitava, as well as the spring wheat Leguan, received the best long-term evaluations. The highest level of resistance was detected for the PSR 3628 line (a hybrid of wheat and couch-grass), but in connection with a low agronomic value. The WKL91-138 line of spring wheat and some varieties (lines) with the detected moderate level of resistance, in particular, could offer good prospects for use in breeding. The presence of the Bdv2 gene was expressed only in the reduction of virus content on the 11 th day after inoculation. Nevertheless, genotypes carrying this gene were evaluated in field trials as susceptible or very susceptible to infection with the Czech PAV isolate. Similarly, the presence of the Bdv1 gene detected with the help of WMS130 marker was no assurance of an increased level of resistance to BYDV. Hybridological analyses of crosses with the WKL91-138 line showed a polygenic nature of inheritance. Thus, the marker-assisted selection does not obviously promise success without a focus on detecting a larger number of QTLs.

The grain of six standard wheat cultivars and one high-amylose wheat cultivar was ground and milled to produce common white flour used to prepare bread, biscuits and wafers. Changes in rapidly and slowly digestible starch (RDS and SDS), resistant starch (RS) and fibre caused by different milling and by the preparation of bakery products were observed. Depending on the milling process, RDS ranged from 28.3 to 32.4% of dry matter and SDS from 18.3 to 35.2%. The preparation of bakery products increased RDS by 30-80% to the detriment of SDS. RS comprised on average 6.6% of ground grain, 3.9% of wheat flour and 3.5, 5.9 and 1.0% of bread, biscuits and wafers, respectively. Variance amongst standard wheat cultivars was low, with only the highamylose wheat showing unique technological and nutritional properties. RS and total starch (TS) were measured using two different methods. TS determinations correlated closely, although the linear regression varied amongst the different matrices. The correlation between RS values measured by the two methods was loose, and no significant linear regression was found. The article brings new information on variability in starch digestibility in cereal products depending on wheat cultivar used for production.

  To determine wheat quality, an experimental 80 g variant (mini-RMT) of the standard 1050 g Rapid Mix Test (RMT) was developed. Ten samples of wheat flour with known RMT values were analysed using the method. Results showed a strong correlation between RMT and mini-RMT values (r = 0.96). Mini-RMT bread volumes were smaller on average by 47.4 ml. A regression equation was constructed allowing the mini-RMT to be used in place of the RMT in wheat breeder laboratories. Anyway, these results are of limited plausibility due to the limited sample numbers and have to be verified on a larger sample set.

Abstract:The effect of selection for two donor-QTL from Fusarium head blight (FHB) resistant spring wheat variety Sumai 3 on the reduction of deoxynivalenol (DON) content and FHB index was evaluated in field trials over two years (2008, 2009) following artificial inoculation with Fusarium culmorum. This study was conducted on populations of recombinant inbred lines derived from two crosses, Sumai 3/Swedget and Sumai 3/SG-S 191-01. DON content and FHB index were significantly reduced in both crosses in the genotype classes with two stacked donor QTL on chromosomes 3B and 5A in comparison to genotype classes with no donor QTL. In the cross Sumai 3/Swedget the selection for QTL alleles from 3B and 5A resulted in a 63.4% reduction in DON content, and a 51.8% reduction in the FHB index. Similarly, there was a 35.9% and 31.9% reduction, respectively, in the cross Sumai 3/SG-S 191-01. The single effect of the donor-QTL allele from 3B was significant only in the cross Sumai 3/Swedjet. The presence or absence of awns affected both DON content and FHB index in both populations, but was only significantly in the cross Sumai 3/SG-S 191-01. In this cross the effect of selection for fully awned genotypes was particularly evident on a reduction of both DON and FHB index in classes with neither donor QTL, or the 3B QTL. However, the data indicate that the "awnedness" effect on FHB resistance may be highly variable and is probably greater on reducing FHB symptoms than on DON content. The results confirmed that marker-based introgression of resistance QTLs on chromosomes 3B and 5A in traditional breeding materials can enrich populations for resistance types, but it was also shown that the effect of marker-based selection need not be large in all crosses and a similar effect can probably be reached by indirect selection for some FHB-related traits.

Abstract:In barley, soil-borne viruses of the barley mosaic virus complex (BaYMV, BaMMV, BaYMV-2) are of high importance due to their increased spread, yield losses, and the fact that protection with chemicals is not possible. Concerning resistance breeding, simple, cheap, and robust selection methods are required. Markerassisted selection (MAS) has a great potential to meet this demand. A CAPS marker designed directly for SNPs causing mutations responsible for resistance of rym4/rym5 alleles of the hv-eIF4e gene was developed in this study. Results showed perfect correspondence between the CAPS marker and the allele identified indirectly on the basis of field tests.