Transfer of resistance against the beet cyst nematode from radish (Raphanus sativus) to rape (Brassica napus) by monosomic chromosome addition.

In rape ( Brassica napus), no resistance to the beet cyst nematode (BCN) Heterodera schachtii is available. This study was carried out to determine the specific chromosome(s) of resistant radish ( Raphanus sativus) carrying the gene(s) for nematode resistance as a prequisite to convert rape from a host into a trap crop for this pest. A Raphanobrassica progeny of 25 plants was analyzed which segregated for all nine chromosomes of the Raphanus genome in a genetic background of synthetic rape. The number of radish chromosomes was determined by fluorescence in situ hybridization, using the Raphanus-specific DNA probe pURsN; and their type was identified by chromosome-specific randomly amplified polymorphic DNA markers. Five different multiple rape-radish chromosome additions (comprising the whole set of nine radish chromosomes, a-i) were selected and crossed to rape. For each cross-progeny, the number of cysts on plant roots was counted 42 days after inoculation with a L2 larvae suspension. Simultaneously, the plants were characterized for the presence or absence of individual radish chromosomes, using sets of chromosome-specific markers. Thus, the effect of each radish chromosome on cyst number was tested. Chromosome d had a major resistance effect, whereas the presence/absence of the other radish chromosomes had nearly no influence on cyst number. Plants with added chromosome d showed a resistance level comparable with that of the radish donor parent. The analysis in the cross to rape of a plant monosomic only for chromosome d confirmed the strong effect of this chromosome on nematode resistance. A further experiment comprising seven crosses using winter rape breeding lines and monosomic addition line d as pollen parent provided the same results on a broader genetic basis. In each case, the added chromosome d in a single dosage caused nearly the full resistance of the radish donor. Resistance was independent of the glucosinolate content in the roots. The possibilities for stabilizing BCN resistance in rape and its use for other crops and nematodes are discussed.

Karyotype analysis of Helianthus annuus using Giemsa banding and fluorescence in situ hybridization.

The karyotype of H. annuus was analysed by computer-aided image processing with respect to the chromosome length, arm ratio, occurrence and chromosomal position of intercalary heterochromatin and the location of 18S/25S and 5S ribosomal RNA genes. The karyotype was subdivided into a group of four acrocentric chromosome pairs, of which two were distinguishable by HKG (HCl, KOH, Giemsa) banding and a group of 13 meta- to submetacentric pairs. The latter could be subdivided into seven pairs with one and six pairs with two HKG bands. Three pairs of submetacentric satellite chromosomes revealed 18S/25S rDNA loci after fluorescence in situ hybridization (FISH) and silver staining. A fourth, smaller and possibly inactive, locus occurred in the terminal position on a metacentric pair. One submetacentric satellite chromosome pair revealed a 5S rRNA gene locus in the pericentromeric position; a second locus marked a submetacentric pair with one HKG band. The C-banding technique marks exclusively centromeric heterochromatin. Measurements of chromosomes in combination with Giemsa banding and FISH enabled the discrimination of most chromosome pairs of the sunflower.

Karyotyping of three Pinaceae species via fluorescent in situ hybridization and computer-aided chromosome analysis.

The positions of 18/25S rRNA genes, 5S RNA genes and of Arabidopsis-type telomeric repeats were localized by fluorescent in situ hybridization (FISH) on the chromosomes of three coniferous species; Picea abies, Larix decidua and Pinus sylvestris, each with 2n=24 chromosomes. Computer-aided chromosome analysis was performed on the basis of the chromosome length, the arm length ratio and the position of the hybridization signals. This enabled the chromosomes of the Norway spruce, 4 chromosomes of the European larch and 3 of the karyotype of the Scots pine to be individually distinguished. With respect to the chromosomal positions of rDNA and 5S rDNA loci, chromosome pair I of P. sylvestris is suggested to be homoeologous to pair II of P. abies, while another chromosome pair of P. sylvestris might be homoeologous to chromosome pair III of L. decidua.

[Chromosome analysis for determining paternity using the AMBA/R-Chro-H image evaluation system]. / Chromosomenanalyse zur Vaterschaftsfeststellung mit dem Bildauswertesystem AMBA/R-Chro-H.

A version of the software package AMBA/R-CHRO developed by the Institute of Breeding Research Quedlinburg and by the Institute of Forensic Medicine, Friedrich-Schiller-University Jena, which is suited for the evaluation of banded human chromosomes, is presented. The parameter which are required for paternity diagnostics (absolute length of the chromosomes, absolute and relative length of the heterochromatin block near the centromere) were automatic registrated and calculated. The way of presenting the chromosomes of interest (A 1, C 9, E 16, Y), their grey-value profiles and their schematic representation make understanding, especially for nonexpert clients, easy. The present software package rationalizes work in the cytogenetic laboratory by reducing objectively and personally conditioned error sources. In addition to this, considerable saving in time is reached. The software package for the interactive automatic microscope image analysis primary developed for using in analysis of vegetable chromosomes finds a new range of application in the field of settlement of paternity cases.