Schriften zu Genetischen Ressourcen - Genres

Identification of novel interspecific hybrids between Hordeum vulgare and Hordeum bulbosum
bulbosum (2n = 28) are useful because multivalent formation regularly occurs at
metaphase-1 (PICKERING 1988).
A crossing programme was initiated to develop novel interspecific hybrids between H.
vulgare and individual H. bulbosum accessions. First results of the hybridisation
programme are given in the present report.
Material and methods
Plant material
Eleven plants derived from crosses between the diploid cultivars ‘Borwina’, ‘Nickel’ and
‘Igri’ (2n = 2x = 14) as female parents and three different tetraploid H. bulbosum
accessions (2n = 4x = 28) as pollinators were analysed. Two H. bulbosum parents were
from Bulgaria, the third one was from the Botanical Garden Montevideo (Uruguay). All
wild species accessions are resistant to barley yellow mosaic virus complex (BaMMV,
BaYMV-1 and -2), powdery mildew, leaf rust and snow mold. One of them shows an
additional resistance to barley yellow dwarf virus (BYDV) (MICHEL 1996). At 15-20 days
after pollination, embryos were isolated and regenerated in vitro.
Chromosome counts
Up to four root tips of individual plants were observed to check their somatic
chromosome numbers. Chromosome counting was carried out by the standard Feulgen
technique.
Isozyme marker analysis
Progenies were electrophoretically assayed for three enzyme loci. The enzyme markers
studied were: two leucine aminopeptidase (Lap2, Lap3) loci and one glutamate
oxaloacetate transaminase (Got1) locus. Lap2 is located on chromosome 4H, Lap3 on
chromosome 7H (KOEBNER and MARTIN 1989) and Got1 is located on chromosome 6H
(RUGE et al. unpublished). Isozymes were assessed according to the protocols of HART
et al. (1980).
Molecular marker analysis
Interspecific hybrids were identified using EST-derived barley microsatellite markers
(RAMSAY et al. 2000). SSR assays were performed as described previously (HACKAUF
and WEHLING 2002).
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