In order to construct an RFLP map of barley, two populations were analyzed using 251 genomic and cDNA markers: one population comprised 71 F1 antherderived double haploid (DH) individuals of an intraspecific cross (IGRI x FRANKA), and the other 135 individuals of an interspecific F2/F3 progeny (VADA x H. spontaneum). The distribution of nonrepetitive clones over the seven barley chromosomes revealed a maximum for chromosome 2H and a minimum for 6H. The polymorphism of the interspecific progeny (76%) clearly exceeded that of the intraspecific progeny (26%) although, based on their pedigrees, IGRI and FRANKA are only distantly related. The contribution of individual chromosomes of the DH parents to the overall polymorphism varied between 8% and 50%. A significant portion (44% versus 10% of the interspecific progeny) of the markers mapped on the DH offspring showed distorted segregation, caused mainly by the prevalence of variants originating from the parent that better responded to in vitro culture (IGRI). In contrast to the interspecific map, probes displaying skewed segregation were clustered on the DH map on discrete segments. The colinear arrangement of both maps covers a distance of 1,453 cM and identifies regions of varying map distances.

Two hundred and fifty doubled haploid lines were studied from a cross between two 2-row winter barley varieties. The lines were evaluated for several characters in a field experiment for 3 years on two locations with two replications. From a total of 431 RFLP probes 50 were found to be polymorphic and subsequently used to construct a linkage map. Quantitative trait loci (QTLs) were determined and localized for resistance against Rhynchosporium secalis and Erysiphe graminis, for lodging, stalk breaking and ear breaking tendency, for the physical state before harvest, plant height, heading date, several kernel parameters and kernel yield. The heritability of the traits ranged from 0.56 to 0.89. For each trait except for kernel thickness, QTLs have been localized that explain 5-52% of the genetic variance. Transgressive segregation occurred for all of the traits studied.

The inheritance of extreme resistance to PVY (Ry (sto)) by a single dominant locus was confirmed by obtaining a 1:1 segregation ratio in a virus inoculation test with 28 resistant (Ryry) to 29 susceptible (ryry) anther culture-derived dihaploid lines (2n=2x=24) from cv. "Assia" (2n=4x=48) having extreme resistance derived from Solanum stoloniferum in simplex constitution (Ryryryry). Twelve Ry (sto) markers selected in AFLP assays using bulked segregant analysis were applied to 106 tested potato cultivars from Germany, The Netherlands and Poland and 19 potato cultivars were identified by these markers as extremely resistant to PVY in alignment with phenotypic data. The locus for extreme resistance (Ry (sto)) to PVY was mapped on chromosome XII co-segregating with the SSR marker STM 0003. The utility of anther-culture derived dihaploid potatoes for genetic marker development was demonstrated. Marker transferability from diploids to tetraploids provides an optimistic potential for marker-assisted selection in potato breeding programs.

Background: In traditional vine areas, the production should present a typicity that partly depends on the grapevine variety. Therefore, vine improvement is considered difficult because of the limited choice in the natural variability of the cultivars within the limits of their characteristics. A possibility to circumvent this problem is the use of somatic variability. In vitro somatic embryogenesis and organogenesis can lead to genotypic and phenotypic variations, described as somaclonal variation, that could be useful for the selection of improved grapevine genotypes.

The techniques of microspore and protoplast regeneration starting from dihaploid Solanum tuberosum plants has been improved to such an extent that the production of more than 2000 microspore derived A1 plant lines and of several hundred protoplast derived plantlets has become possible. Further, from the dihaploid Solanum species S. phureja the regeneration of microspores to plants, and from the species S. infundibuliforme, S. sparsipilum and S. tarijense the regeneration of protoplasts to calluses, has been achieved. The plants descending from the two single cell culture systems are compared with reference to phenotypic markers and economic qualities. Some principles characteristic for either microspore or protoplast derived plants are examined and their significance is discussed. The results are compiled into an extended analytical synthetic breeding scheme based on a stepwise reduction of the autotetraploid to the monohaploid level and a subsequent controlled combination to a new synthetic completely heterozygous tetraploid potato.