Genomic in-situ hybridization (GISH) was applied to study the behaviour of addition chromosomes in first and second backcross (BC) progenies of hybrids between Brassica napus ssp. napus L. (AACC, 2n = 38) and Sinapis alba L. (SS, 2n = 24) produced by electrofusion. With GISH using genomic DNA of S. alba was used as probe it was possible to clearly distinguish both of the parental genomes and effectively monitor the fate of S. alba chromosomes in the BC(1) and BC(2) progenies. GISH analysis confirmed the sesquidiploid genome composition (AACCS) of the BC(1) progenies, which contained 38 chromosomes from B. napus and 12 chromosomes from S. alba. Genome painting in the pollen mother cells (PMCs) of the BC(1) plants revealed intergenomic association between B. napus and S. alba chromosomes, whereby a maximum of 4 trivalents between AC and S chromosomes were identified at metaphase I. In the BC(2) progenies, aneuploids with different numbers of additional chromosomes from S. alba, ranging from 1 to 7, were confirmed. Three putative monosomic alien addition lines were characterized, and the results are discussed with respect to the potential for intergenomic chromosome recombination.

A protocol for Agrobacterium tumefaciens-mediated transformation of Brassica napus mesophyll protoplasts is described. A strain with a neomycin phosphotransferase (nptII) gene and a KCS gene under control of a napin promoter was used at co-cultivation. Transformed protoplasts were regenerated to fertile and morphologically normal transgenic plants. Transformants were confirmed by PCR of the nptII gene and NAP/KCS expression cassette, and Southern blot analysis. Seeds of the transformants showed a changed fatty acid profile: two transformants had a higher erucic acid level and differed significantly from that of B. napus. Genetic analysis of the progeny revealed that the kanamycin resistance introduced was inherited in a Mendelian fashion.

Intergeneric somatic hybridization between Brassica napus and Raphanus sativus was carried out to enrich gene pool of B. napus. Twelve somatic hybrids were produced via PEGmediated protoplast fusion between B. napus and R. sativus. The hybridity was confirmed by morphological observation and molecular marker analysis. Hybrid progenies (BC 1 ) were obtained via backcrosses with B. napus. Behaviour of R. sativus chromosomes in a B. napus background in the F 1 and BC 1 plants was revealed by genomic in situ hybridization (GISH). The potential of somatic hybridization to enrich the suitable gene pool for rapeseed breeding is discussed.

Intertribal somatic hybrids of Brassica napus and Camelina sativa were developed by protoplast electrofusion. Hybrid identity of the regenerants was determined using flow cytometric analysis of nuclear DNA content and simple sequence repeat (SSR) marker analysis. Three hybrids exhibited specific bands for B. napus and C. sativa. These hybrids showed intermediate leaf, flower and seed morphology compared with the two parental species. The seeds of these three hybrids had a modified fatty acid profile, indicating higher level of linolenic and eicosanoic acids than those of B. napus. Our results suggest that somatic hybridization offers opportunities for transferring entire genomes between B. napus and C. sativa in improving rapeseed breeding.

A transformation method using the phosphomannose-isomerase (pmi) gene as a selectable marker was developed for Brassica napus. The pmi-gene, which converts mannose-6-phosphate to fructose-6-phosphate allowing for selection of transgenic plants on mannoseselective medium, was transferred to B. napus hypocotyl explants by Agrobacterium-mediated transformation. More than 350 transgenic plants from three rapeseed varieties were obtained with transformation frequencies up to 24.2% when a combination of 4.5 g l -1 mannose and 10 g l -1 sucrose was used in the selection medium. For early identification of transgenic plants, histochemical staining with 5-bromo-4-chloro-3-indolyl-b-D-glucuronide (X-Gluc) was used. Stable integration of the transgene was confirmed by PCR and Southern blot analysis. Mannose can be used as selective agent to identify transgenic plants in progeny i.e. segregation analysis. These results indicate that the mannose-selection system can be successfully used for Agrobacterium-mediated transformation of rapeseed.