Triticale (X Triticosecale Wittm.) is a hybrid derived by crossing wheat (Triticum sp.) and rye (Secale sp.). Till date, only a limited number of simple sequence repeat (SSRs) markers have been used in triticale molecular analyses and there is a need to identify dedicated high-throughput molecular markers to better exploit this crop. The objective of this study was to develop and evaluate diversity arrays technology (DArT) markers in triticale. DArT marker technology offers a high level of multiplexing. Development of new markers from triticale accessions was combined with mining the large collection of previously developed markers in rye and wheat. Three genotyping arrays were used to analyze a collection of 144 triticale accessions. The polymorphism level ranged from 8.6 to 23.8% for wheat and rye DArT markers, respectively. Among the polymorphic markers, rye markers were the most abundant (3,109) followed by wheat (2,214) and triticale (719). The mean polymorphism information content values were 0.34 for rye DArT markers and 0.37 for those from triticale and wheat. High correlation was observed between similarity matrices derived from rye, triticale, wheat and combined marker sets, as well as for the cophenetic values matrices. Cluster analysis revealed genetic relationships among the accessions consistent with the agronomic and pedigree information available. The newly developed triticale DArT markers as well as those originated from rye and wheat provide high quality markers that can be used for diversity analyses and might be exploited in a range of molecular breeding and genomics applications in triticale.

Cereal cyst nematodes (Heterodera avenae Woll.) are economically damaging barley parasites in most cereal growing areas of the world and the development of resistant cultivars is the best measure against the pathogen. An ISSR (inter-simple sequence repeat) marker identified as closely linked with the H. avenae race 1 and 2 resistance gene (Ha2) has been converted into a codominant sequence characterized amplified region marker (Ha2S18) and mapped in barley 'SW Buddy' x 'SW Cecilia' DH population at 4.3 cM from the Ha2 locus on the long arm of chromosome 2H. The potential usefulness of Ha2S18 in large scale marker assisted selection schemes has been evaluated in a broad genetic background and is an important complement to the bioassay and to other linked DNA-markers for this trait.

To examine changes in the level of and pattern in variability in 197 Nordic and Baltic spring barley cultivars over time we used 21 mapped barley simple sequence repeats (SSRs). A total number of 191 alleles were found from 22 SSR loci. The number of alleles per locus ranged from 2 to 23, with average of 8.63 107 alleles were rare (frequency <0.05) among the cultivars and only one allele was frequently observed (frequency >0.95). The gene diversity between loci in Nordic and Baltic material varied between 0.033 and 0.891. Average gene diversity was 0.623. The SSR data separated two-rowed and six-rowed cultivars. According to analysis of molecular variance (AMOVA) differentiation in two-rowed vs six-rowed accounted for 23.6% of the total variation. Overall no significant decrease of average gene diversity over time could be found. However, differences were observed when spring barleys from northern (north of ∼58°) and southern (south of ∼58°) parts of the Nordic and Baltic area were compared. For the southern ecogeographical region significant decrease of genetic diversity was observed in the middle of the 20th century, whereas no significant changes in the northern part were found. We found larger differentiation between modern and old cultivars in the South compared to the ones in North parts of the region. The magnitude of changes in genetic diversity differed also with the country of origin. Danish cultivars had a significant decrease in diversity in the middle of century, whereas changes in Finland, Norway and Sweden were not significant.

Powdery mildew is a common disease of field pea, Pisum sativum L., and is caused by the ascomycete fungus Erysiphe pisi. It can cause severe damage in areas where pea is cultivated. Today breeders want to develop new pea lines that are resistant to the disease. To make the breeding process more efficient, it is desirable to find genetic markers for use in a marker-assisted selection (MAS) strategy. In this study, microsatellites (SSR) were used to find markers linked to powdery mildew resistance. The resistant pea cultivar '955180' and the susceptible pea cultivar 'Majoret' were crossed and F2 plants were screened with SSR markers, using bulked segregant analysis. A total of 315 SSR markers were screened out of which five showed linkage to the powdery mildew resistance gene. No single marker was considered optimal for inclusion in a MAS program. Instead, two of the markers can be used in combination, which would result in only 1.6% incorrectly identified plants. Thus SSR markers can be successfully used in marker-assisted selection for powdery mildew resistance breeding in pea.

Eleven Chinese and twelve Swedish rapeseed (Brassica napus) genotypes were analysed by PCR with 41 microsatellite primers, generating a total of 50 loci. For these 50 loci, the number of alleles ranged from 1 to 14, and the average number of alleles per loci was 2.7. As an example of simple sequence repeat (SSR) scoring in Metaphor agarose gel, a single marker could distinguish 14 different DNA profiles. Based on cluster analysis (UPGMA), the dendrogram clearly distinguished three clusters, a cluster with exclusively Swedish genotypes, and two clusters with Chinese genotypes. The genetic diversity within the Chinese genotypes was broad compared to the genetic diversity within the Swedish material. The genetic similarity within the Swedish breeding lines ranged from 69.5 to 95.6%, while that of Chinese genotypes ranged from 57.1 to 81.6%. The results in this report will permit to establish a set of microsatellite primers that can be used for selecting appropriate parents for Brassica napus hybrids and for monitoring hybridity level.

This study evaluates putative changes of genetic diversity and relationships of barley in the Nordic and Baltic countries that might have taken place during the last century as a result of commercial breeding. Four ISSR primers were used to analyse 227 accessions, yielding a total of 47 polymorphic loci. Shannon-Weaver diversity values for each locus ranged from 0.012 to 0.693. Overall, there were no significant changes of genetic diversity observed over time. A significant decrease of diversity was, however, observed in material from the southern parts of the Nordic and Baltic countries. In material from the northern parts no decrease of diversity was observed. The genetic diversity of six-rowed barley bred in the middle of the 20th century was low, but there was no significant difference between modern accessions and landraces or old cultivars. The magnitude in changes of genetic diversity differed also in material from different countries of origin. A cluster analysis clearly separated the material into two groups. The first cluster included 86.5% of all six-rowed accessions, whereas the second cluster contained 97.4% of all two-rowed accessions.

Three quantitative trati loci (QTL) regions for the restoration of Owen CMS (cytoplasmic male sterility) in sugar beet (Beta vulgaris L.ssp. vulgaris) were identified through analysis of three populations segregating for genes restoring the fertility of cytoplasmic male sterile plants. Two large populations, A and B, were studied by means of 51 and 42 polymorphic and evenly distributed restriction fragment length polymorphism (RFLP) markers, respectively. A smaller population, C, was analyzed by use of six RFLP markers. Composite interval mapping in Population A detected a strong signal on linkage group IV that explained 79% of the phenotypic variation. More detailed analysis revealed the presence of two linked QTL on this chromosome. In Population B, a QTL that explained 72% of the phenotypic variation was detected at one end of linkage group III. Single-marker analysis of Population C resulted in significant signals for markers on linkage group IV, explaining 57% of the phenotypic variation. In each of the two large populations, what appeared to be minor alleles were also detected in the QTL regions.

A total of 568 new simple sequence repeat (SSR)-based markers for barley have been developed from a combination of database sequences and small insert genomic libraries enriched for a range of short simple sequence repeats. Analysis of the SSRs on 16 barley cultivars revealed variable levels of informativeness but no obvious correlation was found with SSR repeat length, motif type, or map position. Of the 568 SSRs developed, 242 were genetically mapped, 216 with 37 previously published SSRs in a single doubled-haploid population derived from the F1 of an interspecific cross between the cultivar Lina and Hordeum spontaneum Canada Park and 26 SSRs in two other mapping populations. A total of 27 SSRs amplified multiple loci. Centromeric clustering of markers was observed in the main mapping population; however, the clustering severity was reduced in intraspecific crosses, supporting the notion that the observed marker distribution was largely a genetical effect. The mapped SSRs provide a framework for rapidly assigning chromosomal designations and polarity in future mapping programs in barley and a convenient alternative to RFLP for aligning information derived from different populations. A list of the 242 primer pairs that amplify mapped SSRs from total barley genomic DNA is presented.

A total of 257 parental wheat and 38 triticale lines were used for anther culture. On average, 2.1 green wheat haploids were obtained per spike. This response occurred irrespective of the origin of the material (Germany, France, Sweden or UK) and 5 years of testing. Triticale responded with 5.3 green haploids per spike. Using the criterion that one parental line should give at least one green haploid per spike in the screening experiment, green haploids were produced from 88 out of 91 F-1 wheat breeding combinations and from each of 21 F-1 and F-2 triticale bleeding combinations. An average of 4.7 green plants were obtained per spike from the wheat production programme, while the triticale programme gave an average of 6.2 green plants per spike. A single medium supplemented with different hormones for anthers and embryos was used for culture of both crops.

The inheritance of Cercospora leaf spot resistance in sugar beet was investigated by means of quantitative trait loci (QTL) analysis of a segregating population of 204 individuals, using 221 AFLP and 46 restriction fragment length polymorphism (RFLP) markers. Five QTL were found through composite interval mapping on linkage groups 1, 2, 3, and 9, respectively, two of which were linked on linkage group 3. The significance of these QTL was tested by permutation analysis. The QTL had mostly additive, but also certain negative dominance effects; all the resistance alleles came from the Cercospora-resistant parent. Each quantitative trait locus accounted for 7-18% of the phenotypic variation, leaving 37% of the variation unexplained. The results are discussed in relation to the potential use of marker-assisted breeding for Cercospora leaf spot resistance in sugar beet.

The aim of this investigation was to develop a procedure for the large-scale molecular breeding for ym4, allowing resistance to BaMMV/BaYMV to be fixed in early breeding generations of winter barley. A codominant STS marker derived from the restriction fragment length polymorphism marker MWG838 for the ym4 resistance gene was combined with a new and easy procedure for preparing leaf samples for polymerase chain reaction (PCR), theoretically allowing one person to extract DNA from 5000 samples in a single day. In the procedure for molecular breeding for ym4, all steps, including leaf sampling, DNA extraction, PCR amplification and digestion with restriction enzyme were assembled in microtitre plates allowing multipipetting throughout the procedure, including the loading of gels. The method is amenable to further automation with the aid of a robot arm. Double haploid (DH) lines, as well as F-2 and F-4 breeding lines were analysed and, based on markers, homozygous and heterozygous BaMMV/BaYMV-resistant plants were identified for further breeding. The winter barley breeding programmes were modified to include marker-based selection for BaMMV/BaYMV resistance on DH or on F-2 individuals, which had been preselected for mildew and leaf rust resistance.

The study describes the genetic structure in sugar beets and in wild beets (Beta vulgaris) using 30 RFLP markers. Samples consisting of pooled plant material of 100 individuals from each line and population were used to analyse 120 sugar beet breeding lines and 91 wild beet populations. Greater variation was found among the wild populations than among the breeding lines. Although the two major groups of breeding lines, monogerm and multigerm, had approximately equal amounts of genetic variation, in the monogerm group more of this variation was partitioned among the Lines than within the lines. Furthermore, despite most of the variation being shared by the two groups, the two groups were found to be separated along the first two components in a principal component analysis. Computer simulations were carried out to evaluate the usefulness of the pooled-sample strategy employed in the investigation. These simulations showed the use of pooled samples to be a better alternative than that of analysing a few plants individually.

A high density sugar beet RFLP map with an average distance of 1.5 cM between markers has been constructed. The map covers 621 cM and includes 413 markers distributed over the nine linkage groups of sugar beet. The map is based on two F2populations representing two different pairs of parents. The two sets of data were integrated into a single map using 90 markers that were common to both data sets. The quality of the map was assessed in several ways. The common markers were used to investigate how often the loci had been mapped in the same order in the two F2populations. For closely situated markers (<1.5 cM) the order specified in the map is uncertain, but for markers separated by more than 2 cM the locus order is highly reliable. The error rate of the overall process was estimated at 0.3% by independently repeating the analysis of 41 markers. The map is comparatively short, with a map length corresponding to approximately 1.4 crossovers per bivalent. Another feature of the map is a high degree of clustering of markers along the linkage groups. With the possible exception of linkage group 2, each linkage group shows one major cluster, which in most cases is situated in the centre of the linkage group. Our interpretation is that sugar beet, in comparison with most other species, has an extreme localization of recombination. Key words : sugar beet, linkage, RFLP, clustering.

DNA sequences from a sugar beet genomic library were tested for their ability to crosshybridize and detect RFLPs in 40 accessions representing 13 different species and subspecies. A set of 32 sugar beet DNA sequences was categorized as either single copy non-polymorphic (SCN), single copy polymorphic (SCP), low copy repeated (LCR), or high copy repeated (HCR). The crosshybridization of these DNA sequences was analyzed at two different stringencies. At medium stringency, 12 of the DNA sequences hybridized exclusively to accessions from the section Beta, whereas 16 also crosshybridized to accessions from the section Procumbentes. Accessions from the related genus Atriplex showed crosshybridization for 13 of the DNA sequences. At low stringency, 94% of the sugar beet SCP sequences crosshybridized to the Procumbentes accessions, indicating that most of these sequences will crosshybridize with the majority of the species in the genus Beta. High levels of polymorphisms among the wild beets from the section Beta indicate that marker-guided backcross programmes are feasible using sugar beet genomic clones. The sugar beet DNA sequences also detected a considerable amount of RFLP variation among the Procumbentes and Atriplex accessions. This reflects the general usefulness of these markers in comparative genome mapping projects within the genus Beta. In another experiment, 87 clones were used in Northern hybridizations to estimate the proportion of transcribed sequences present in the genomic library. In total, 17 clones detected transcripts.