Katalin Puskás

Barley (Hordeum vulgare L.) Marker Linkage Map: A Case Study of Various Marker Types and of Mapping Population Structure

A barley mapping population consisting of 96 doubled haploid lines of anther culture origin was developed from the varieties Dicktoo and Kompolti Korai, which represent diverse types with respect to geographical origin and ecological adaptation. Several molecular marker techniques were used in mapping: among the markers with known chromosome location, RFLP, STS and SSR markers were applied to identify linkage groups and for comparative mapping, while RAPD and AFLP markers, which have random binding but provide useful information on polymorphism, were employed to fill in the linkage groups with markers. A total of 496 markers were tested in the DH population, 246 of which were included in the linkage map after eliminating markers that were completely linked with each other. The ratio of markers with known chromosome location to random markers in the 1107 cM map was one to three, and the mean recombination distance between the markers was 4.5 cM. Application of various marker methods and the effect of the population structure on the development of marker linkage maps are discussed.

Identification of wheat genotypes with adult plant resistance to powdery mildew

As in the case of other wheat diseases, adult plant resistance (APR) to powdery mildew remains effective longer than monogenic hypersensitive resistance, so the objective was to identify winter wheat genotypes with this type of resistance. Field and greenhouse tests conducted on 41 varieties and breeding lines indicated that 36 were susceptible in the seedling stage, and only five were resistant in all stages of development. It is probable that these latter genotypes contain major resistance genes. The area under the disease progress curve was the same for most of the wheat genotypes as for the APR control variety Massey, but varieties and lines with significantly better resistance were also identified. Among the genotypes in the Martonvasar breeding stock, Mv Taltos and the line Mv07-03 were found to have excellent adult plant resistance.

Study of Fusarium head blight resistance in wheat using microsatellite markers

Investigations on Fusarium head blight (FHB) in wheat are gaining importance throughout the world. This can be attributed to the fact that Fusarium species not only cause yield losses, but also produce mycotoxins in infected plant tissues, the accumulation of which makes the grain unsuitable for both human and animal consumption (Larsen et al. 2004). Nowadays spring genotypes of Far Eastern origin are considered to have the best resistance, so these are generally used as basic material in studies on the genetic background of resistance. Several types of resistance have been described in wheat on the basis of the plants defence mechanisms (Mesterhdzy et al. 1999), but in most cases genetic analysis is focussed on Type II resistance, i.e. resistance to the spread of the fungus within the spike, since the use of point inoculation allows it to be examined separately from Type I resistance, which prevents the penetration of the fungus into the spike tissue. (Schroeder and Christensen 1963). The other method used to investigate FHB resistance is spray inoculation (Buerstmayr et al. 2003, Schmolke et al. 2005), but the infection data only allow conclusions to be drawn on field resistance, i.e. on the joint effect of the two main types of resistance (Miedaner et al. 2003). Although this inoculation method is used less frequently in the phenotypic analyses required for genetic research, its role should not be underestimated. The present experiments involved the genetic analysis of field resistance in the moderately resistant Chinese line Ning8331 and the moderately susceptible variety Martonvasari 17.

STUDY OF FUSARIUM HEAD BLIGHT RESISTANCE IN OLD HUNGARIAN WHEAT CULTIVARS

2006). Wild relatives of wheat, landraces, and wheat varieties bred several decades ago often contain previously unidentified resistance genes, or chromosome regions influencing disease resistance. It was observed by Borner et al. (2006) that the probability of identifying effective resistance declines as the ploidy level increases, though even in hexaploid varieties and lines there is a 10% chance of success. Investigations on