Schriften zu Genetischen Ressourcen - Genres

M. SCHOLZ, B. RUGE and B. HACKAUF
Identification of novel interspecific hybrids between Hordeum vulgare
and Hordeum bulbosum
M. SCHOLZ, B. RUGE and B. HACKAUF 1
Abstract
A crossing programme was initiated to produce interspecific triploid hybrids between
diploid Hordeum vulgare cultivars (2n = 2x = 14) and some tetraploid H. bulbosum
accessions (2n = 4x = 28). The hybrid nature of the progeny was confirmed by means of
cytological, biochemical and molecular analysis. Most of the plants examined contained
21 chromosomes. The chromosome number of the remainder varied from 19 to 20. This
indicates that aneuploid hybrids occurred by elimination of chromosomes. Using
isozyme and SSR markers, between two and four H. bulbosum chromosomes could be
identified in the offspring. To obtain diploid recombinant barley genotypes with
introgressed H. bulbosum chromatin interspecific hybrids have to be selfed or
backcrossed to H. vulgare.
Introduction
Hordeum bulbosum belongs to the secondary genepool of Hordeum. Since it contains a
variety of different resistance genes, H. bulbosum has potential value as genetic
resource for barley breeding. Recombinants between H. vulgare L. and H. bulbosum L.
have rarely been obtained due to chromosome instability in hybrids, low intergenomic
chromosome pairing and low crossing over (PICKERING 1992). Nevertheless, interspecific
crosses have resulted in the transfer of novel resistance genes conferring resistance to
powdery mildew (KASHA et al. 1996), leaf rust (PICKERING et al. 2000) and the soilborne
virus complex (RUGE et al. 2000), respectively. Using molecular markers, the dominantly
inherited resistances were mapped on H. bulbosum introgressions located on
chromosomes 2HL, 2HS and 6HS, respectively. As a starting point for the introgression
of H. bulbosum genes into barley, triploid hybrids between H. vulgare (2n = 14) and H.
1 Federal Centre for Breeding Research on Cultivated Plants
Institute of Agricultural Crops
Rudolf-Schick-Platz
D-18190 Groß Lüsewitz, Germany
321