Triple hybridization with cultivated barley (Hordeum vulgare L.).

A crossing programme for trispecific hybridization including cultivated barley (Hordeum vulgare L.) as the third parent was carried out. The primary hybrids comprised 11 interspecific combinations, each of which had either H. jubatum or H. lechleri as one of the parents. The second parent represented species closely or distantly related to H. jubatum and H. lechleri. In trispecific crosses with diploid barley, the seed set was 5.7%. Crosses with tetraploid barley were highly unsuccessful (0.2% seed set). Three lines of diploid barley were used in the crosses, i.e. 'Gull', 'Golden Promise' and 'Vada'. Generally, cv 'Gull' had high crossability in crosses with related species in the primary hybrid. It is suggested that 'Gull' has a genetic factor for crossability not present in cv 'Vada' and cv 'Golden Promise'. One accession of H. brachyantherum used in the primary hybrid had a very high crossability (seed set 54.7%) in combination with cv 'Vada' but no viable offspring was produced. In all, two trispecific hybrids were raised, viz. (H. lechleri x H. brevisubulatum) x 'Gull' (2n=7-30) and (H. jubatum x H. lechleri) x 'Gull' (2n=20-22). The first combination invariably had a full complement of seven barley chromosomes plus an additional chromosome no. 7, but a varying number of chromosomes (19-22) of the wild-species hybrid. The second combination had a full set of barley chromosomes. The meiotic pairing was low in both combinations.